[moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Thu Oct 18 2007, 05:50PMHi all! Been a while since posting here....I have not had as much time to experiment lately, though that is changing. I've been dabbling in high voltage lately, rather than launchers...my latest experiments and builds can be seen on my YouTube page:
However, EM Launchers are my favorite...I am about to build a massive induction launcher. Whereas my existing discharge system was 3.5kj, my new one will be 24kj...that's not a typo...24,000 joules of energy...I have the capacitors already and will be building my bank soon. I do not know where on earth I'd find an SCR capable of switching that much current, so I'm thinking of building a large solenoid fired relay. My first coils will be about a foot in diameter, and single layer. I'll post as construction gets under way!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Simon, Fri Oct 19 2007, 03:53AM
24kJ? Wow. o_o
I'll bet you'll vaporise a lot of stuff trying to make that happen. Make sure you post pics, whatever happens!
Simon, Fri Oct 19 2007, 03:53AM
24kJ? Wow. o_o
I'll bet you'll vaporise a lot of stuff trying to make that happen. Make sure you post pics, whatever happens!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
andy73, Fri Oct 26 2007, 04:03PM
hi good luck, hope you dont kill yourself or a load of kit in the process, remember less is more....
andy73, Fri Oct 26 2007, 04:03PM
hi good luck, hope you dont kill yourself or a load of kit in the process, remember less is more....
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Quantum Singularity, Sun Oct 28 2007, 05:31AM
Good to see your still at it man. I got to get back into it myself... my aquarium hobbies taking up most my time nowadays.
So what kind of caps you using? I'd hope with that much energy you scored some Maxwell pulse caps? Or you just making a really big array of lytics? You could probably use scr's if you had lots of money to burn, but I'd hope you have a high enough operating voltage you could simply use a spark gap switch. I'm building one very similar to Bert H.'s for when I get around to using my Maxwells (1.5" solid brass rods for contacts - machined, solenoid triggered). Oh and BTW I cant view youtube at work...and my home internet is down temporarily. I;ll have to remember to check out your stuff when I get a chance.
Quantum Singularity, Sun Oct 28 2007, 05:31AM
Good to see your still at it man. I got to get back into it myself... my aquarium hobbies taking up most my time nowadays.
So what kind of caps you using? I'd hope with that much energy you scored some Maxwell pulse caps? Or you just making a really big array of lytics? You could probably use scr's if you had lots of money to burn, but I'd hope you have a high enough operating voltage you could simply use a spark gap switch. I'm building one very similar to Bert H.'s for when I get around to using my Maxwells (1.5" solid brass rods for contacts - machined, solenoid triggered). Oh and BTW I cant view youtube at work...and my home internet is down temporarily. I;ll have to remember to check out your stuff when I get a chance.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
TodX, Wed Nov 14 2007, 12:38PM
A 24kJ bank is damn impressive.
I thought you might be interested in these SCRs I found recently.
I actually just bought some for a Thompson coil/jumping ring CG I'm planning of building.
They're rated at 6000A@10mS pulse. If you're staying under 600v on the caps, then these
should work great for that massive cap bank.
TodX, Wed Nov 14 2007, 12:38PM
A 24kJ bank is damn impressive.
I thought you might be interested in these SCRs I found recently.
I actually just bought some for a Thompson coil/jumping ring CG I'm planning of building.
They're rated at 6000A@10mS pulse. If you're staying under 600v on the caps, then these
should work great for that massive cap bank.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Nov 14 2007, 08:51PM
So I've finally gotten all the main bus bars on the capacitors....this bank will be configured for 4500v @ 2400uf.....enough energy to do some serious launching:
See my youtube vids to see what I've done with 3500j of energy....and imagine what 24,000j will do
FastMHz, Wed Nov 14 2007, 08:51PM
So I've finally gotten all the main bus bars on the capacitors....this bank will be configured for 4500v @ 2400uf.....enough energy to do some serious launching:
See my youtube vids to see what I've done with 3500j of energy....and imagine what 24,000j will do
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Shaun, Wed Nov 14 2007, 09:14PM
My god man...thats insane!
Where/how did you score all those lytics?
BTW an AK47 bullet has 5kJ of kinetic energy...
Shaun, Wed Nov 14 2007, 09:14PM
My god man...thats insane!
Where/how did you score all those lytics?
BTW an AK47 bullet has 5kJ of kinetic energy...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Ken M., Wed Nov 14 2007, 10:06PM
DEAR LORD!!!! Is all I really have to say, but that looks more like it would crush any metal that was near not even needing to be inside the coil.
Ken M., Wed Nov 14 2007, 10:06PM
DEAR LORD!!!! Is all I really have to say, but that looks more like it would crush any metal that was near not even needing to be inside the coil.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Nov 14 2007, 10:11PM
To give an idea of the size of the bank....here's a pic of my caps and I:
FastMHz, Wed Nov 14 2007, 10:11PM
To give an idea of the size of the bank....here's a pic of my caps and I:
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Sulaiman, Thu Nov 15 2007, 12:59AM
Nice Stack !
That's quite scary = hope you've got good eye, ear and body protection!
Anyway, have you considered re-arranging the capacitors and bars?
I would be tempted to put 5 capacitors on one bar, with alternate spaces.
Put another 5 capacitors the other side of the bar in the 'spaces'
(all the capacitors sitting flat as currently, with the bars on top)
continue .....
so you would end up with say TWO banks of (5 caps in parallel x 10 caps in series).
Two rigid simple banks with low esr.
Even electrolytics can discharge quite quickly so compact/low-inductance is probably worth considering too.
Sulaiman, Thu Nov 15 2007, 12:59AM
Nice Stack !
That's quite scary = hope you've got good eye, ear and body protection!
Anyway, have you considered re-arranging the capacitors and bars?
I would be tempted to put 5 capacitors on one bar, with alternate spaces.
Put another 5 capacitors the other side of the bar in the 'spaces'
(all the capacitors sitting flat as currently, with the bars on top)
continue .....
so you would end up with say TWO banks of (5 caps in parallel x 10 caps in series).
Two rigid simple banks with low esr.
Even electrolytics can discharge quite quickly so compact/low-inductance is probably worth considering too.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Simon, Thu Nov 15 2007, 01:18AM
That bank is a thing of beauty!
Any progress on silicon?
Simon, Thu Nov 15 2007, 01:18AM
That bank is a thing of beauty!
Any progress on silicon?
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Thu Nov 15 2007, 02:03AM
Hi all! This thing will be remote control and mechanically triggered...I don't want to be near whatever is hooked to it! I'm thinking giant copper rod, spring loaded, with a release pulled by an RC servo that I trigger via remote control. The giant spring will pull the rod into a giant copper plate to complete the circuit.
The caps are wired this way because it was cleanest, and they are 10 separate banks of 10 in parallel (each string weighs a ton, and I'm not a huge person to lug a massive bank around, so 10 sets are good for me!!). This gives ample flexibility, though with induction large capacitance isn't very useful since the platter is far away rather quickly and all extra energy is wasted...so I figure more volts, less uF, so it's a really short, HUGE pulse....I suspect my first few coils might detonate until I figure out how large they must be to absorb this much energy.
I'm also thinking coin shrinking might be in my sights
FastMHz, Thu Nov 15 2007, 02:03AM
Hi all! This thing will be remote control and mechanically triggered...I don't want to be near whatever is hooked to it! I'm thinking giant copper rod, spring loaded, with a release pulled by an RC servo that I trigger via remote control. The giant spring will pull the rod into a giant copper plate to complete the circuit.
The caps are wired this way because it was cleanest, and they are 10 separate banks of 10 in parallel (each string weighs a ton, and I'm not a huge person to lug a massive bank around, so 10 sets are good for me!!). This gives ample flexibility, though with induction large capacitance isn't very useful since the platter is far away rather quickly and all extra energy is wasted...so I figure more volts, less uF, so it's a really short, HUGE pulse....I suspect my first few coils might detonate until I figure out how large they must be to absorb this much energy.
I'm also thinking coin shrinking might be in my sights
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Shaun, Thu Nov 15 2007, 03:01AM
Coin shrinking, right...
I saw a pic of a coin shrunk w/ a 12kJ bank that compressed the coin so much it ended up rod-shaped, with the bond between the copper and nickel in the coin broken so the two metals were clearly separated. Wonder what 24kJ will do?
On another note, what kind of sound will this thing make when that spring-loaded copper rod hits the plate? I'm sure it will be epic...
And on another note, YAY 200TH post!!!
Shaun, Thu Nov 15 2007, 03:01AM
Coin shrinking, right...
I saw a pic of a coin shrunk w/ a 12kJ bank that compressed the coin so much it ended up rod-shaped, with the bond between the copper and nickel in the coin broken so the two metals were clearly separated. Wonder what 24kJ will do?
On another note, what kind of sound will this thing make when that spring-loaded copper rod hits the plate? I'm sure it will be epic...
And on another note, YAY 200TH post!!!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Bauerb2, Thu Nov 15 2007, 04:08AM
dear lord....
i am speechless.
Bauerb2, Thu Nov 15 2007, 04:08AM
dear lord....
i am speechless.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Cwazy, Thu Nov 15 2007, 04:23AM
^^ yeah that is crazy.
Cwazy, Thu Nov 15 2007, 04:23AM
^^ yeah that is crazy.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Chris, Thu Nov 15 2007, 04:28PM
Very nice looking capacitor bank, but what sort specs do they have? I hope they are actually worthy of the task. Are they pulse rated? Are they fast? A lot of people just use computer grade... If there's a 1% chance of a cap failing and you have 100 caps in a bank, chances are one will fail every shot.
Have you considered making a multi-stage gun with these? That would be ideal since you have so many, and thus so many possibilities to arrange them.
Chris, Thu Nov 15 2007, 04:28PM
Very nice looking capacitor bank, but what sort specs do they have? I hope they are actually worthy of the task. Are they pulse rated? Are they fast? A lot of people just use computer grade... If there's a 1% chance of a cap failing and you have 100 caps in a bank, chances are one will fail every shot.
Have you considered making a multi-stage gun with these? That would be ideal since you have so many, and thus so many possibilities to arrange them.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Thu Nov 15 2007, 06:47PM
These are the same brand and type of caps that I've been using in my 3.5kj bank, never a failure and awesome discharge rates as can be seen in my induction launcher videos
FastMHz, Thu Nov 15 2007, 06:47PM
These are the same brand and type of caps that I've been using in my 3.5kj bank, never a failure and awesome discharge rates as can be seen in my induction launcher videos
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Quantum Singularity, Fri Nov 16 2007, 02:55AM
Nice job man... but I fear the biggest challenge will be designing a coil to withstand that energy. I've talked to Bert H a few times big induction launcher design... one thing I think I can tell you if your seriously going to blast all that into a single stage your not going to be able to epoxy up a coil and have it hold together... it wont. You might have to design it with something like a thin layer of something compressible between the turns, I forget exactly what he told me off hand but something along the lines of teflon tape.
Have you given any thought to making something multi stage? Thats something I hope to work on in the future... I think if a good efficient design can be made for IL's to be multi stage would mean a lot.
Keep us posted!
Quantum Singularity, Fri Nov 16 2007, 02:55AM
Nice job man... but I fear the biggest challenge will be designing a coil to withstand that energy. I've talked to Bert H a few times big induction launcher design... one thing I think I can tell you if your seriously going to blast all that into a single stage your not going to be able to epoxy up a coil and have it hold together... it wont. You might have to design it with something like a thin layer of something compressible between the turns, I forget exactly what he told me off hand but something along the lines of teflon tape.
Have you given any thought to making something multi stage? Thats something I hope to work on in the future... I think if a good efficient design can be made for IL's to be multi stage would mean a lot.
Keep us posted!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
andy73, Sun Nov 18 2007, 10:29AM
man thats insane!!! good work. i just hope you dont blow you house to bits when you let it fire....i hope you got insurance
andy73, Sun Nov 18 2007, 10:29AM
man thats insane!!! good work. i just hope you dont blow you house to bits when you let it fire....i hope you got insurance
Re: [moved] 24,000j Capacitor Bank (Now Complete)
rp181, Sun Nov 18 2007, 04:05PM
O.o how are you gonna charge that beast?
rp181, Sun Nov 18 2007, 04:05PM
O.o how are you gonna charge that beast?
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sun Nov 18 2007, 05:38PM
Charging will be accomplished via two MOTs in inverted phase series...I still need to find two identical MOTs though...
FastMHz, Sun Nov 18 2007, 05:38PM
Charging will be accomplished via two MOTs in inverted phase series...I still need to find two identical MOTs though...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Derek_L, Sun Nov 18 2007, 10:04PM
I have a feeling this is going to be 4hv's first snuff film :P
Derek_L, Sun Nov 18 2007, 10:04PM
I have a feeling this is going to be 4hv's first snuff film :P
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Mon Nov 19 2007, 02:41AM
lol......hence my remotely controlled trigger....I don't want to be near it!!!!
FastMHz, Mon Nov 19 2007, 02:41AM
lol......hence my remotely controlled trigger....I don't want to be near it!!!!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Shaun, Mon Nov 19 2007, 06:15AM
I wouldn't want to be near 24kJ going off in a fraction of a second, either...especially if the coil (or some other component) should decide to explode.
Shaun, Mon Nov 19 2007, 06:15AM
I wouldn't want to be near 24kJ going off in a fraction of a second, either...especially if the coil (or some other component) should decide to explode.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Kizmo, Thu Nov 22 2007, 07:48AM
Nice bank you got there!
I think i should do the same, friend of mine (who works at local power station) said that they have few hundred 350VDC/3300uF capacitors taken from large inverter. I could get them for free :D
That is HUGE pile of capacitors.
Kizmo, Thu Nov 22 2007, 07:48AM
Nice bank you got there!
I think i should do the same, friend of mine (who works at local power station) said that they have few hundred 350VDC/3300uF capacitors taken from large inverter. I could get them for free :D
That is HUGE pile of capacitors.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Barry, Thu Nov 22 2007, 07:13PM
... pulls out a calculator ... hmm ... 3300uF @ 350VDC works out to 200 joules each!
You can build a heckuva coilgun with just a small bank of those caps. You could even build a really nice low-power demonstrator with just one capacitor. And then go into production mode selling them as christmas toys. Umm, no wait, there just might be some safety agency who could have just a tiny little problem with that.
Cheers, Barry
Heck is for those who don't believe in gosh.
Barry, Thu Nov 22 2007, 07:13PM
... pulls out a calculator ... hmm ... 3300uF @ 350VDC works out to 200 joules each!
You can build a heckuva coilgun with just a small bank of those caps. You could even build a really nice low-power demonstrator with just one capacitor. And then go into production mode selling them as christmas toys. Umm, no wait, there just might be some safety agency who could have just a tiny little problem with that.
Cheers, Barry
Heck is for those who don't believe in gosh.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
JoeDarkon, Thu Nov 22 2007, 10:05PM
maybe you can build something to compete with the latest navy railgun : )
JoeDarkon, Thu Nov 22 2007, 10:05PM
maybe you can build something to compete with the latest navy railgun : )
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sat Dec 01 2007, 01:50AM
I've totally redesigned fastmhz.com into a blog where I'll be putting the juicy little tidbits relating to this project as it progresses....I'll of course update this thread time to time as well. Cheers! ~FM
FastMHz, Sat Dec 01 2007, 01:50AM
I've totally redesigned fastmhz.com into a blog where I'll be putting the juicy little tidbits relating to this project as it progresses....I'll of course update this thread time to time as well. Cheers! ~FM
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Jasonr, Fri Dec 14 2007, 10:35PM
So are the cans grounded???? if you are running a series parallel situation you will have can cases at different potentials.
Also if one can shorts(which is how it will fail) you will have all the other cans helping it fail that is in parallel with. I suggest you make a case of it. of some kind. Distance may not be a reliable substitute, but in combination with a case or a cover would be.
Jasonr, Fri Dec 14 2007, 10:35PM
So are the cans grounded???? if you are running a series parallel situation you will have can cases at different potentials.
Also if one can shorts(which is how it will fail) you will have all the other cans helping it fail that is in parallel with. I suggest you make a case of it. of some kind. Distance may not be a reliable substitute, but in combination with a case or a cover would be.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Logan Kennedy, Mon Dec 24 2007, 05:02AM
Wow, that's beyond amazing!
I can't wait to see the completed project. The switching mechanism will have to be beyond heavy duty to switch this amount of energy. If it's not designed properly to withstand such a large amount of energy it will NOT survive.
I cannot imagine the blast wave from a 24KJ short circuit.
Logan Kennedy, Mon Dec 24 2007, 05:02AM
Wow, that's beyond amazing!
I can't wait to see the completed project. The switching mechanism will have to be beyond heavy duty to switch this amount of energy. If it's not designed properly to withstand such a large amount of energy it will NOT survive.
I cannot imagine the blast wave from a 24KJ short circuit.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
LarsE, Fri Dec 28 2007, 01:21AM
Nice bank you got there, i am also curious in what you are planing to use as switch.
Someday i have to finish my 28,8Kj bank so i can try my ETG.
LarsE, Fri Dec 28 2007, 01:21AM
Nice bank you got there, i am also curious in what you are planing to use as switch.
Someday i have to finish my 28,8Kj bank so i can try my ETG.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Thu Jan 03 2008, 08:55PM
I’ve found and ordered two identical 1200w MOTs for charging the bank. I have diodes already, and will construct the charging system soon. I’ve also been asking around about discharge systems for such a huge amount of energy, and have settled on an open-air thyratron, aka triggered spark gap using a high voltage plasma. Essentially, a gap is created and a high voltage lightning bolt is created between the gap thus closing the circuit to discharge the bank. I have the remote control unit already for activating the discharge. It now appears that I have almost all the major components!!!
FastMHz, Thu Jan 03 2008, 08:55PM
I’ve found and ordered two identical 1200w MOTs for charging the bank. I have diodes already, and will construct the charging system soon. I’ve also been asking around about discharge systems for such a huge amount of energy, and have settled on an open-air thyratron, aka triggered spark gap using a high voltage plasma. Essentially, a gap is created and a high voltage lightning bolt is created between the gap thus closing the circuit to discharge the bank. I have the remote control unit already for activating the discharge. It now appears that I have almost all the major components!!!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Jasonr, Fri Jan 04 2008, 12:11AM
Well that would work if you don't mind wasting almost all your energy in the spark gap? If it were me I would not go that route.
I know it is way cheaper and easy. but if I could not afford the scrs required I would at least build a solenoid controlled knife switch or push to large copper plates together. Some kind of mechanical contact would be far more efficient.
Jason
Jasonr, Fri Jan 04 2008, 12:11AM
Well that would work if you don't mind wasting almost all your energy in the spark gap? If it were me I would not go that route.
I know it is way cheaper and easy. but if I could not afford the scrs required I would at least build a solenoid controlled knife switch or push to large copper plates together. Some kind of mechanical contact would be far more efficient.
Jason
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Shaun, Fri Jan 04 2008, 03:31AM
I wonder how long ANY type of metal-metal mechanical switch would stand up to repeated shots at 24kJ? Unless you could close the switch extremely fast due to the very short pulse width, it would end up as essentially a spark gap anyway.
Shaun, Fri Jan 04 2008, 03:31AM
I wonder how long ANY type of metal-metal mechanical switch would stand up to repeated shots at 24kJ? Unless you could close the switch extremely fast due to the very short pulse width, it would end up as essentially a spark gap anyway.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
..., Fri Jan 04 2008, 04:43AM
I would take a look at TDU's switch,
..., Fri Jan 04 2008, 04:43AM
I would take a look at TDU's switch,
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Fri Jan 04 2008, 05:35PM
Thanks for the feedback guys....yeah a spark gap really is my only option...any mechanical contact will weld together or just detonate, and any SCR big enough to handle it will cost more than a shiny new car....I've been researching triggered gaps, and properly designed ones can indeed transfer most of the energy successfully, and have rapid "switch-on" times as well. If they weren't that useful, high energy research labs wouldn't use them to switch mega-amps of current. I'm all for alternative affordable switching methods, of course
FastMHz, Fri Jan 04 2008, 05:35PM
Thanks for the feedback guys....yeah a spark gap really is my only option...any mechanical contact will weld together or just detonate, and any SCR big enough to handle it will cost more than a shiny new car....I've been researching triggered gaps, and properly designed ones can indeed transfer most of the energy successfully, and have rapid "switch-on" times as well. If they weren't that useful, high energy research labs wouldn't use them to switch mega-amps of current. I'm all for alternative affordable switching methods, of course
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Jan 09 2008, 02:36AM
PROBLEM: I experienced an unexplained diode failure today. I strung 4 1600v 40a diodes together to form a 6400v block...I took my two identical MOTs and stacked them in inverted phase fashion. Next I hooked them up with the diodes to a meter to test the RMS charge potential for my cap bank....and the entire string blew at about 4500 volts.....why would this happen?
FastMHz, Wed Jan 09 2008, 02:36AM
PROBLEM: I experienced an unexplained diode failure today. I strung 4 1600v 40a diodes together to form a 6400v block...I took my two identical MOTs and stacked them in inverted phase fashion. Next I hooked them up with the diodes to a meter to test the RMS charge potential for my cap bank....and the entire string blew at about 4500 volts.....why would this happen?
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Shaun, Wed Jan 09 2008, 03:30AM
Were the MOTs in series? At 4400 volts RMS that gives 6.2kV peak, way too close to your strings rating.
If there's no load on the MOTs either, why not just use some cheap 1n4007s in series to test charging DC voltage?
It has to suck to lose those nice diodes, though. I would be very pissed...
Shaun, Wed Jan 09 2008, 03:30AM
Were the MOTs in series? At 4400 volts RMS that gives 6.2kV peak, way too close to your strings rating.
If there's no load on the MOTs either, why not just use some cheap 1n4007s in series to test charging DC voltage?
It has to suck to lose those nice diodes, though. I would be very pissed...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Jan 09 2008, 03:56AM
Yes, the MOTs were in series, and on a variac....I didn't have the variac all the way up, and the meter was only reading 4500v when the string blew...that's why I'm confused...and yes, POed too!
FastMHz, Wed Jan 09 2008, 03:56AM
Yes, the MOTs were in series, and on a variac....I didn't have the variac all the way up, and the meter was only reading 4500v when the string blew...that's why I'm confused...and yes, POed too!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Electroholic, Wed Jan 09 2008, 04:21AM
why use 40A silicons when a string of cheap 4007(1A) or 5408(3A) would do the job? you can also look at Conner's mot voltage doubler, robust enough to use in a TC. IIRC he used caps and resistors in parallel with the diodes in the string to balance the voltage a little better.
Electroholic, Wed Jan 09 2008, 04:21AM
why use 40A silicons when a string of cheap 4007(1A) or 5408(3A) would do the job? you can also look at Conner's mot voltage doubler, robust enough to use in a TC. IIRC he used caps and resistors in parallel with the diodes in the string to balance the voltage a little better.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Jan 09 2008, 06:47AM
I used those diodes because those are what I had laying around...all I wanted to do was a quick voltage test....but I still would like to know why the string fried at 4500v when it should have taken that easily.
FastMHz, Wed Jan 09 2008, 06:47AM
I used those diodes because those are what I had laying around...all I wanted to do was a quick voltage test....but I still would like to know why the string fried at 4500v when it should have taken that easily.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
..., Wed Jan 09 2008, 07:29AM
was there any significant load on the mot when the diodes blew? Since you are only halfwave rectifying the output the cycle that is not being used will probably peak much higher than the voltage on the cap bank... Especially with a bank this large that could easliy pull enough current to drop the mots voltage considerably...
..., Wed Jan 09 2008, 07:29AM
was there any significant load on the mot when the diodes blew? Since you are only halfwave rectifying the output the cycle that is not being used will probably peak much higher than the voltage on the cap bank... Especially with a bank this large that could easliy pull enough current to drop the mots voltage considerably...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Jasonr, Wed Jan 09 2008, 03:14PM
Did you have any kind of current limiting? Caps will act like a short when quick changes in voltage occur. A variac is a way to attempt to limit the current however dirty brushes or any spike at all on the input is exponential on the output.
You need either a current limit resistor, or a ballast of some kind.
another thing is powering up the MOT's with no load you could have overvolted the diodes very easily.
Jason
Jasonr, Wed Jan 09 2008, 03:14PM
Did you have any kind of current limiting? Caps will act like a short when quick changes in voltage occur. A variac is a way to attempt to limit the current however dirty brushes or any spike at all on the input is exponential on the output.
You need either a current limit resistor, or a ballast of some kind.
another thing is powering up the MOT's with no load you could have overvolted the diodes very easily.
Jason
Re: [moved] 24,000j Capacitor Bank (Now Complete)
EN, Wed Jan 09 2008, 05:39PM
the failure is totally normal, similar things happened to me on a smaller scale.
when you charge caps with a halfwave rectifier, the unused halfwave adds to the voltage of the capacitor, and kills the diode, if it can not stand twice the voltage.
EN, Wed Jan 09 2008, 05:39PM
the failure is totally normal, similar things happened to me on a smaller scale.
when you charge caps with a halfwave rectifier, the unused halfwave adds to the voltage of the capacitor, and kills the diode, if it can not stand twice the voltage.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Jan 09 2008, 07:10PM
Alright...so it seems to be a halfwave overvolt problem...I suppose my alternative is to make a bridge, or to make a string to handle much higher voltages, with a rather large safety margin.
FastMHz, Wed Jan 09 2008, 07:10PM
Alright...so it seems to be a halfwave overvolt problem...I suppose my alternative is to make a bridge, or to make a string to handle much higher voltages, with a rather large safety margin.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sun Jan 13 2008, 08:17PM
Great news - my charger appears to be working as needed. I bought some new 8kv diodes and made a bridge rectifier out of them...repeated the same test and charged a 1uf cap up to 5kv, which is a safety margin 500v more than I'll need since my 24kj bank is 4500v.
Next step is to build my remote controlled triggered spark gap. I plan to use a 10kv ignition transformer as the initiator.
FastMHz, Sun Jan 13 2008, 08:17PM
Great news - my charger appears to be working as needed. I bought some new 8kv diodes and made a bridge rectifier out of them...repeated the same test and charged a 1uf cap up to 5kv, which is a safety margin 500v more than I'll need since my 24kj bank is 4500v.
Next step is to build my remote controlled triggered spark gap. I plan to use a 10kv ignition transformer as the initiator.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Jasonr, Sun Jan 20 2008, 06:14AM
I wonder if when you test it on your bank you don't over current you diodes. I think you had both over volt and over current happening.
Jason
Jasonr, Sun Jan 20 2008, 06:14AM
I wonder if when you test it on your bank you don't over current you diodes. I think you had both over volt and over current happening.
Jason
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Tue Jan 22 2008, 07:34AM
The capacitor bank has been completely bussed together for the first time!!! The system, including charger, went “live†the other day for the first time, charging to 1% of the total energy capacity. I will not charge higher until I complete the remote controlled discharge unit, as I have no other safe way to discharge the system. I am also using an IR thermometer to monitor the diode temps to ensure that I'm not drawing too much current and overheating them.
FastMHz, Tue Jan 22 2008, 07:34AM
The capacitor bank has been completely bussed together for the first time!!! The system, including charger, went “live†the other day for the first time, charging to 1% of the total energy capacity. I will not charge higher until I complete the remote controlled discharge unit, as I have no other safe way to discharge the system. I am also using an IR thermometer to monitor the diode temps to ensure that I'm not drawing too much current and overheating them.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Jan 30 2008, 08:13PM
I’ve built the charger into a self contained unit, with integrated cooling to keep everything operating at peak performance. With the charger now a self contained unit, I intend to charge the system from a safe distance, in addition to the previously planned remote discharging. Components fail…bad things can happen, and I don't ever want to be near the bank while it's charged…the charger:
FastMHz, Wed Jan 30 2008, 08:13PM
I’ve built the charger into a self contained unit, with integrated cooling to keep everything operating at peak performance. With the charger now a self contained unit, I intend to charge the system from a safe distance, in addition to the previously planned remote discharging. Components fail…bad things can happen, and I don't ever want to be near the bank while it's charged…the charger:
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Shaun, Wed Jan 30 2008, 09:30PM
What do you use for current limiting on the charger? A big power resistor, or maybe a series capacitor on the AC side?
Without it theres a good chance of overcurrent on the diodes, or even the MOTs. If the diodes really do stand up to 40A, I think they'll survive. But you could blow a breaker; 2400W worth of MOTs will charge this bank in 10s running at maximum power. Thats 20A draw right there, assuming they don't go over...
Shaun, Wed Jan 30 2008, 09:30PM
What do you use for current limiting on the charger? A big power resistor, or maybe a series capacitor on the AC side?
Without it theres a good chance of overcurrent on the diodes, or even the MOTs. If the diodes really do stand up to 40A, I think they'll survive. But you could blow a breaker; 2400W worth of MOTs will charge this bank in 10s running at maximum power. Thats 20A draw right there, assuming they don't go over...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
teravolt, Thu Jan 31 2008, 03:36AM
nice bank does it have gradeing resistors for equal charging? Be careful it is a pausible explosion hazard
teravolt, Thu Jan 31 2008, 03:36AM
nice bank does it have gradeing resistors for equal charging? Be careful it is a pausible explosion hazard
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Thu Jan 31 2008, 05:57AM
I have 3 fuses in my charger...one on the input, and on each MOT output before the diodes...this way, I can't possibly over-current my diodes, or overload the charger's built in variac I'm using to slowly ramp up the charge on the bank - the variac is my current limiting. In my experimentation so far I've found the strings charging to within a couple of volts of each other, they are really well matched; and of course I will keep monitoring this as I use the bank to ensure that an individual string never gets "out of line".
I was thinking...what about placing a clamping diode on each string? The diodes would prevent any individual string from being reverse charged... The problem then is where to find diodes big enough to handle this...x 10
FastMHz, Thu Jan 31 2008, 05:57AM
I have 3 fuses in my charger...one on the input, and on each MOT output before the diodes...this way, I can't possibly over-current my diodes, or overload the charger's built in variac I'm using to slowly ramp up the charge on the bank - the variac is my current limiting. In my experimentation so far I've found the strings charging to within a couple of volts of each other, they are really well matched; and of course I will keep monitoring this as I use the bank to ensure that an individual string never gets "out of line".
I was thinking...what about placing a clamping diode on each string? The diodes would prevent any individual string from being reverse charged... The problem then is where to find diodes big enough to handle this...x 10
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Shaun, Thu Jan 31 2008, 06:37AM
Oh yea, thats another good point...what kind of diodes will stand up to back EMF from a 24kJ bank? Well, whatever type of diode you pick, encase it in something because after the coil itself I think the flywheel diode is most likely to detonate.
I want to make a suggestion better than a bunch of big brick diodes in parallel, but its late (early?), and I can't think of any.
Shaun, Thu Jan 31 2008, 06:37AM
Oh yea, thats another good point...what kind of diodes will stand up to back EMF from a 24kJ bank? Well, whatever type of diode you pick, encase it in something because after the coil itself I think the flywheel diode is most likely to detonate.
I want to make a suggestion better than a bunch of big brick diodes in parallel, but its late (early?), and I can't think of any.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
teravolt, Fri Feb 01 2008, 05:15AM
depending on age and condition I don't think it will be necisary if each bank is balanced and exersized.
teravolt, Fri Feb 01 2008, 05:15AM
depending on age and condition I don't think it will be necisary if each bank is balanced and exersized.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
teslacoolguy, Fri Feb 01 2008, 09:56PM
i would be afraid that the cap bank will not stand up to such high reverse voltage but than again i might be wrong
teslacoolguy, Fri Feb 01 2008, 09:56PM
i would be afraid that the cap bank will not stand up to such high reverse voltage but than again i might be wrong
Re: [moved] 24,000j Capacitor Bank (Now Complete)
ramses, Sat Feb 02 2008, 02:58AM
if it couldn't take it, it would SUCK to loose 100 cap's just like that. i have no idea what i would do to myself if i did that. i have heard of aluminum strips in electrolyte being kind of a rectifier, conducting in one direction and not in the other. i don't know if 'lyics act the same way, but my 'lyics conduct when the polarity is wrong. as long as you don't use a SCR(good luck finding one) they should ring down unless your coil blows, but i wouldn't risk it without research, life insurance, and something to hide behind.
just stay away from inductive loads and you should be fine :( happy diode hunting!
ramses, Sat Feb 02 2008, 02:58AM
if it couldn't take it, it would SUCK to loose 100 cap's just like that. i have no idea what i would do to myself if i did that. i have heard of aluminum strips in electrolyte being kind of a rectifier, conducting in one direction and not in the other. i don't know if 'lyics act the same way, but my 'lyics conduct when the polarity is wrong. as long as you don't use a SCR(good luck finding one) they should ring down unless your coil blows, but i wouldn't risk it without research, life insurance, and something to hide behind.
just stay away from inductive loads and you should be fine :( happy diode hunting!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Tue Feb 05 2008, 06:45PM
My small scaled triggered spark gap worked 100% reliably!!!!! I successfully remote control discharged a 5kv capacitor by turning on an ignition transformer with a remote button. It worked as low as 1.5kv up to 5kv. I figure on the full scale one the electrodes should be easily adjustable so that voltages as low as 500v can be used, hopefully. I don't want to be stuck only being able to discharge a fully loaded bank as that severely limits experimentation potential.
FastMHz, Tue Feb 05 2008, 06:45PM
My small scaled triggered spark gap worked 100% reliably!!!!! I successfully remote control discharged a 5kv capacitor by turning on an ignition transformer with a remote button. It worked as low as 1.5kv up to 5kv. I figure on the full scale one the electrodes should be easily adjustable so that voltages as low as 500v can be used, hopefully. I don't want to be stuck only being able to discharge a fully loaded bank as that severely limits experimentation potential.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Thu Feb 07 2008, 07:31PM
I've finally got my full scale triggered gap complete!
The entire system has now been completed....my full size triggered spark gap works like a charm. I charged the 24kj bank to a low value of ~3.5kj and discharged into a coil a couple of times....except I have a problem...the 10kv transformer on the gap is backfeeding to my main charger and fried the diodes, which are 8kv. So I either need to disconnect the charger from the bank before discharging, or find diodes of higher voltage to put in the charger.
After sleeping on this problem, I've decided I'm going to disconnect the charger completely. Total isolation is the only surefire way to eliminate all unanticipated possibilities of things backfeeding into it....because who knows what might get sent back when 24kj discharges across that gap :-o
I plan to do some 5kj shots today to see how it stands up to repetition. Those spark gap knobs are solid brass on the inside. The individual cap strings are sitting at about 7 volts each after a discharge, none of them reversed. The spark gap is built on slots in the base, so I can spread or close the gap by loosening the bolts. I'm able to discharge as low as 1kv.
Full power discharge is getting closer!!!!!
FastMHz, Thu Feb 07 2008, 07:31PM
I've finally got my full scale triggered gap complete!
The entire system has now been completed....my full size triggered spark gap works like a charm. I charged the 24kj bank to a low value of ~3.5kj and discharged into a coil a couple of times....except I have a problem...the 10kv transformer on the gap is backfeeding to my main charger and fried the diodes, which are 8kv. So I either need to disconnect the charger from the bank before discharging, or find diodes of higher voltage to put in the charger.
After sleeping on this problem, I've decided I'm going to disconnect the charger completely. Total isolation is the only surefire way to eliminate all unanticipated possibilities of things backfeeding into it....because who knows what might get sent back when 24kj discharges across that gap :-o
I plan to do some 5kj shots today to see how it stands up to repetition. Those spark gap knobs are solid brass on the inside. The individual cap strings are sitting at about 7 volts each after a discharge, none of them reversed. The spark gap is built on slots in the base, so I can spread or close the gap by loosening the bolts. I'm able to discharge as low as 1kv.
Full power discharge is getting closer!!!!!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Backyard Skunkworks, Fri Feb 08 2008, 05:10AM
Whoa!
This is totally insane!
This has got to be one of the coolest electrical projects of all time!
I remember reading something somewhere about being able to get water to explode very violently when discharging this kind of energy through it, maybe that would be another experiment?
EDIT:
A quick googling turned up the page, http://www.eskimo.com/~billb/amateur/capexpt.html. That guy had a 33.75kJ bank @150kV and did a few crazy things including coin shrinkage, exploding water and other items, etc.
Backyard Skunkworks, Fri Feb 08 2008, 05:10AM
Whoa!
This is totally insane!
This has got to be one of the coolest electrical projects of all time!
I remember reading something somewhere about being able to get water to explode very violently when discharging this kind of energy through it, maybe that would be another experiment?
EDIT:
A quick googling turned up the page, http://www.eskimo.com/~billb/amateur/capexpt.html. That guy had a 33.75kJ bank @150kV and did a few crazy things including coin shrinkage, exploding water and other items, etc.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Andyman, Fri Feb 08 2008, 06:33AM
Cool! I hopefully will try to use a triggered gap on my 800v bank. It's going to be tough though, the gap will have to be only a few thousandths of an inch. But that will be easier with a feeler gauge.
It would be interesting to try and contain the exploding water and use it to accelerate a projectile...
Andyman, Fri Feb 08 2008, 06:33AM
Cool! I hopefully will try to use a triggered gap on my 800v bank. It's going to be tough though, the gap will have to be only a few thousandths of an inch. But that will be easier with a feeler gauge.
It would be interesting to try and contain the exploding water and use it to accelerate a projectile...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Fri Feb 08 2008, 11:35PM
Success!!...I built a giant knife switch to completely isolate the charger from the bank before discharge....problem solved!!! So I began having some fun at lower energies of around 5kj last night. First I fired an induction coil with a harddrive platter into a 5gal plastic bucket, which left a clear indentation of the platter in the bottom of the bucket. Cool I said, so I connected the outputs to a CD-R. KaaaaaaaaaBAMMMMMMM it went....the shockwave was immense, I felt it across the room...the foil detonated with a ferocity I've never seen, and the smell of burnt plastic filled the air as the disc got so hot it warped. I do plan to detonate a CD-R at 24kj eventually I need to build some rather large induction coils to handle the full energy too, so that I can launch some rather large "rockets", since that's what I most enjoy doing with these things. Large thermo-cannons would be fun as well if I can ever have one fabricated strong enough to withstand the pressures.
FastMHz, Fri Feb 08 2008, 11:35PM
Success!!...I built a giant knife switch to completely isolate the charger from the bank before discharge....problem solved!!! So I began having some fun at lower energies of around 5kj last night. First I fired an induction coil with a harddrive platter into a 5gal plastic bucket, which left a clear indentation of the platter in the bottom of the bucket. Cool I said, so I connected the outputs to a CD-R. KaaaaaaaaaBAMMMMMMM it went....the shockwave was immense, I felt it across the room...the foil detonated with a ferocity I've never seen, and the smell of burnt plastic filled the air as the disc got so hot it warped. I do plan to detonate a CD-R at 24kj eventually
I need to build some rather large induction coils to handle the full energy too, so that I can launch some rather large "rockets", since that's what I most enjoy doing with these things. Large thermo-cannons would be fun as well if I can ever have one fabricated strong enough to withstand the pressures.Re: [moved] 24,000j Capacitor Bank (Now Complete)
Simon, Sat Feb 09 2008, 03:02AM
Congratulations! Can we have some pics?
Simon, Sat Feb 09 2008, 03:02AM
Congratulations! Can we have some pics?
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sat Feb 09 2008, 05:28AM
Pics and video will be forthcoming soon
I've just built a rolling cart for the cap bank to make it more mobile, as it takes my entire workbench up at the moment. I'm going to enclose the base of the cart to make it a cabinet as well to store all the components together, such as charger, gap, cables, etc.
FastMHz, Sat Feb 09 2008, 05:28AM
Pics and video will be forthcoming soon
I've just built a rolling cart for the cap bank to make it more mobile, as it takes my entire workbench up at the moment. I'm going to enclose the base of the cart to make it a cabinet as well to store all the components together, such as charger, gap, cables, etc.Re: [moved] 24,000j Capacitor Bank (Now Complete)
Backyard Skunkworks, Mon Feb 11 2008, 12:58AM
Haha, just read the "Thermoelectric Cannon Construction" thread and it looks like the exploding water thing is old news. Still looks cool though.
Backyard Skunkworks, Mon Feb 11 2008, 12:58AM
Haha, just read the "Thermoelectric Cannon Construction" thread and it looks like the exploding water thing is old news. Still looks cool though.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Tesladownunder, Sat Mar 01 2008, 10:42AM
I am late to find this thread.
Nice stuff. A few comments.
You are likely to blow your electrolytics with ringing if you are feeding into a coil. On can crushing I was getting 60 - 80% ringing. I doubt that your electrolytics will like that reverse voltage and (16kJ coming in backwards).
I used token big diodes and a heavy resistor for my small 1.5kJ bank to catch the reverse ringing but I cannot stop the energy of my big bank.
I suggest you try this lots of times with 1 cap and equivalent proportional load. Preferably look at the waveform with a CRO.
That's why pulse caps are used for this sort of stuff not electrolytics and even they have a limited reverse rating too which is 20% reversal for my Aerovox caps and 80% for my Maxwell.
My suggestion is enjoy blowing things up with resistive loads. You can get great pics and a fair life for your cap until one fails and explodes and takes out the ones within a couple of feet of it. This is likely to happen very soon if you have an inductive load.
TDU
Tesladownunder, Sat Mar 01 2008, 10:42AM
I am late to find this thread.
Nice stuff. A few comments.
You are likely to blow your electrolytics with ringing if you are feeding into a coil. On can crushing I was getting 60 - 80% ringing. I doubt that your electrolytics will like that reverse voltage and (16kJ coming in backwards).
I used token big diodes and a heavy resistor for my small 1.5kJ bank to catch the reverse ringing but I cannot stop the energy of my big bank.
I suggest you try this lots of times with 1 cap and equivalent proportional load. Preferably look at the waveform with a CRO.
That's why pulse caps are used for this sort of stuff not electrolytics and even they have a limited reverse rating too which is 20% reversal for my Aerovox caps and 80% for my Maxwell.
My suggestion is enjoy blowing things up with resistive loads. You can get great pics and a fair life for your cap until one fails and explodes and takes out the ones within a couple of feet of it. This is likely to happen very soon if you have an inductive load.
TDU
Re: [moved] 24,000j Capacitor Bank (Now Complete)
ramses, Sat Mar 01 2008, 07:28PM
but inductive loads are so much fun... the best thing i can think of is some way to blow the wire when V ~0 and then extinguish the arc somehow (like a massive electromagnet and fans). good luck!
ramses, Sat Mar 01 2008, 07:28PM
but inductive loads are so much fun... the best thing i can think of is some way to blow the wire when V ~0 and then extinguish the arc somehow (like a massive electromagnet and fans). good luck!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Tesladownunder, Sun Mar 02 2008, 01:36AM
Inductive loads are fun but remember that everything has an inductance, from the caps to the busbars and this is the dominant load often in my case even though the circuit path is 24 inches.
Dont think that you can simply turn off a huge magnetic field easily. Huge voltages will develop and the spark will jump across the developing gap of your switch.
Although I haven't documented a lot, My pictures of exploding wire current draw still had ringing not that dissimilar to can crushing. So even a "resistive" load may be primarily inductive.
TDU
Tesladownunder, Sun Mar 02 2008, 01:36AM
Inductive loads are fun but remember that everything has an inductance, from the caps to the busbars and this is the dominant load often in my case even though the circuit path is 24 inches.
Dont think that you can simply turn off a huge magnetic field easily. Huge voltages will develop and the spark will jump across the developing gap of your switch.
Although I haven't documented a lot, My pictures of exploding wire current draw still had ringing not that dissimilar to can crushing. So even a "resistive" load may be primarily inductive.
TDU
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Mon Mar 03 2008, 06:30AM
Hey guys - I'm still around! Didn't blow up or anything :-o I'm actually moving to a new place....I just plain am out of space....and this project is to blame for a lot of that!! It's HUGE. So I'll be out of action for a couple of months, but once my new, vastly expanded shop is done, I'll be able to resume immediately in Spring
FastMHz, Mon Mar 03 2008, 06:30AM
Hey guys - I'm still around! Didn't blow up or anything :-o I'm actually moving to a new place....I just plain am out of space....and this project is to blame for a lot of that!! It's HUGE. So I'll be out of action for a couple of months, but once my new, vastly expanded shop is done, I'll be able to resume immediately in Spring
Re: [moved] 24,000j Capacitor Bank (Now Complete)
101111, Tue Mar 18 2008, 01:16PM
THAT is one insane capacitor bank!
Wonder how many times it can kill and revive you..
101111, Tue Mar 18 2008, 01:16PM
THAT is one insane capacitor bank!
Wonder how many times it can kill and revive you..
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Apr 30 2008, 05:32PM
My electrical experimentation last night ended with the cops showing up....apparently, the neighbors thought a 14,000j discharge into a pickle was too noisy :-o I'll have tons of pictures and new youtube productions soon!
I launched electromagnetic induction rockets, accidentally detonated a coilgun with too much energy and laughed uncontrollably as pickles exploded with incredible ferocity The coilgun was so powerful at 3.8kj that it shot a slug through both sides of a 5-gal pale and almost through sheet metal behind it!!! So I decided to try 5kj...and this happened:
My capacitor bank is 24,000j fully charged....I've only gone up to 14,000 so far....this sucker is insane!!
FastMHz, Wed Apr 30 2008, 05:32PM
My electrical experimentation last night ended with the cops showing up....apparently, the neighbors thought a 14,000j discharge into a pickle was too noisy :-o I'll have tons of pictures and new youtube productions soon!
I launched electromagnetic induction rockets, accidentally detonated a coilgun with too much energy and laughed uncontrollably as pickles exploded with incredible ferocity
The coilgun was so powerful at 3.8kj that it shot a slug through both sides of a 5-gal pale and almost through sheet metal behind it!!! So I decided to try 5kj...and this happened:My capacitor bank is 24,000j fully charged....I've only gone up to 14,000 so far....this sucker is insane!!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Firefox, Thu May 01 2008, 02:18AM
Sheesh, is that 14 AWG? Perhaps soaking your coils in carbon fiber or fiberglass laced gorilla glue would have prevented that? In any case, I can't wait to get my 1kJ photo flash bank together now!
Firefox, Thu May 01 2008, 02:18AM
Sheesh, is that 14 AWG? Perhaps soaking your coils in carbon fiber or fiberglass laced gorilla glue would have prevented that? In any case, I can't wait to get my 1kJ photo flash bank together now!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Electroholic, Thu May 01 2008, 03:47AM
What kind of failure mode is that? inter-turn short from the compression effect of the shot?
Glass and CF are too stiff, kevlar or spectra might work.
Electroholic, Thu May 01 2008, 03:47AM
What kind of failure mode is that? inter-turn short from the compression effect of the shot?
Glass and CF are too stiff, kevlar or spectra might work.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Tesladownunder, Thu May 01 2008, 04:38AM
Otherwise you risk getting them increasingly pissed off.
I have a little concern if you are "accidentally" doing anything with those energies. Have fun but take care.
Also bear in mind that inductive loads plus electrolytics will eventually give cap failure and one of them may go the way of your pickle. I got a bruise from an exploding cap less than 1cm size from overvoltage so your mileage with 14kJ will vary.
TDU
Tesladownunder, Thu May 01 2008, 04:38AM
FastMHz wrote ...
My electrical experimentation last night ended with the cops showing up....apparently, the neighbors thought a 14,000j discharge into a pickle was too noisy :-o
I launched electromagnetic induction rockets, accidentally detonated a coilgun with too much energy and laughed uncontrollably as pickles exploded with incredible ferocity The coilgun was so powerful at 3.8kj that it shot a slug through both sides of a 5-gal pale and almost through sheet metal behind it!!! So I decided to try 5kj...and this happened:
My capacitor bank is 24,000j fully charged.
I would suggest you get your neighbors onside. Explain in a letter, or preferably personally, that you are a mildly eccentric chap that has an electrical lab and will make some noises. Be clear to explain that there are no guns or explosives and that there will be no noise after 9 pm. They are welcome to have a guided tour or have an open day.My electrical experimentation last night ended with the cops showing up....apparently, the neighbors thought a 14,000j discharge into a pickle was too noisy :-o
I launched electromagnetic induction rockets, accidentally detonated a coilgun with too much energy and laughed uncontrollably as pickles exploded with incredible ferocity
The coilgun was so powerful at 3.8kj that it shot a slug through both sides of a 5-gal pale and almost through sheet metal behind it!!! So I decided to try 5kj...and this happened:My capacitor bank is 24,000j fully charged.
Otherwise you risk getting them increasingly pissed off.
I have a little concern if you are "accidentally" doing anything with those energies. Have fun but take care.
Also bear in mind that inductive loads plus electrolytics will eventually give cap failure and one of them may go the way of your pickle. I got a bruise from an exploding cap less than 1cm size from overvoltage so your mileage with 14kJ will vary.
TDU
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Thu May 01 2008, 03:15PM
I totally agree - letting my neighbors know there aren't bombs or something over here is a good idea. Every time I meet a new neighbor I do tell them of my electrical hobbies and that they might hear it. I just hadn't met *all* of them yet as I only moved in on Apr 1st....I'm getting there!
As for accidentally doing stuff....well...coils die, what can I say? My system is remote controlled so I can be really far away from it in case of failure, as I've explained throughout this thread. I've also noticed that my spark gap stops conducting before the bank is completely discharged or reverse charged by the coils - there's always a few hundred volts left in, in the correct polarity. Methinks this is a good thing!
Not sure about the failure mode...but the coil was scrunched up pretty good - I used to be twice as long. It was 3 layers of 50 turns of 14awg. Perhaps I need more layers...
Hopefully I'll get the video edited soon - Almost everything was caught on camera
FastMHz, Thu May 01 2008, 03:15PM
I totally agree - letting my neighbors know there aren't bombs or something over here is a good idea. Every time I meet a new neighbor I do tell them of my electrical hobbies and that they might hear it. I just hadn't met *all* of them yet as I only moved in on Apr 1st....I'm getting there!
As for accidentally doing stuff....well...coils die, what can I say? My system is remote controlled so I can be really far away from it in case of failure, as I've explained throughout this thread. I've also noticed that my spark gap stops conducting before the bank is completely discharged or reverse charged by the coils - there's always a few hundred volts left in, in the correct polarity. Methinks this is a good thing!
Not sure about the failure mode...but the coil was scrunched up pretty good - I used to be twice as long. It was 3 layers of 50 turns of 14awg. Perhaps I need more layers...
Hopefully I'll get the video edited soon - Almost everything was caught on camera
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Tesladownunder, Fri May 02 2008, 12:34AM
Don't assume that you have just discharged 99%. What is more likely is that there have been repeated ringing cycles and what is left is a combination of what no longer has the power to sustain an arc and some recovered charge (when caps recharge themselves a bit). This is what I see on my storage CRO even when the coil is disrupted.
In terms of coil failure, the forces are for axial compression and radial expansion. It explains why the coils scrunch up (making interturn shorts develop) and expand and disrupt at the same time.
To provide some physical restraining force, I have placed my coin shrinking coil in a container wrapped in old cloth. Fill with water and freeze. Any coil explosion then has to disrupt that. Easy to do and no cost. These are the results of 5kJ on a coil of 2mm wire which had fibreglass wrapping between turns.
TDU
Tesladownunder, Fri May 02 2008, 12:34AM
FastMHz wrote ...
I've also noticed that my spark gap stops conducting before the bank is completely discharged or reverse charged by the coils - there's always a few hundred volts left in, in the correct polarity. Methinks this is a good thing!
Not sure about the failure mode...but the coil was scrunched up pretty good - I used to be twice as long. It was 3 layers of 50 turns of 14awg. Perhaps I need more layers...
I've also noticed that my spark gap stops conducting before the bank is completely discharged or reverse charged by the coils - there's always a few hundred volts left in, in the correct polarity. Methinks this is a good thing!
Not sure about the failure mode...but the coil was scrunched up pretty good - I used to be twice as long. It was 3 layers of 50 turns of 14awg. Perhaps I need more layers...
Don't assume that you have just discharged 99%. What is more likely is that there have been repeated ringing cycles and what is left is a combination of what no longer has the power to sustain an arc and some recovered charge (when caps recharge themselves a bit). This is what I see on my storage CRO even when the coil is disrupted.
In terms of coil failure, the forces are for axial compression and radial expansion. It explains why the coils scrunch up (making interturn shorts develop) and expand and disrupt at the same time.
To provide some physical restraining force, I have placed my coin shrinking coil in a container wrapped in old cloth. Fill with water and freeze. Any coil explosion then has to disrupt that. Easy to do and no cost. These are the results of 5kJ on a coil of 2mm wire which had fibreglass wrapping between turns.
TDU
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed May 07 2008, 11:36PM
Thanks for the frozen cloth idea!! I especially like the cost
And anything that makes these suckers safer is a good thing!!
FastMHz, Wed May 07 2008, 11:36PM
Thanks for the frozen cloth idea!! I especially like the cost
And anything that makes these suckers safer is a good thing!!Re: [moved] 24,000j Capacitor Bank (Now Complete)
Bust_A_Cap, Tue Jun 24 2008, 12:47PM
hey i know this is pretty late with the posting, but I was wondering why you didn't decide to put balancing boards on your cap bank?
It seems like your pretty set on having the gun fire a single massive shot, rather than doing multiple stages and what not, but I was thinking you could set up a sweet chainfun style barrel system, consisting of say, 10 cap barrels, and have a cap bank for each of the barrels, you could have it fire all at once or in rapid sucession.
Anyways this is an amazing cap bank and your works is looking great
Bust_A_Cap, Tue Jun 24 2008, 12:47PM
hey i know this is pretty late with the posting, but I was wondering why you didn't decide to put balancing boards on your cap bank?
It seems like your pretty set on having the gun fire a single massive shot, rather than doing multiple stages and what not, but I was thinking you could set up a sweet chainfun style barrel system, consisting of say, 10 cap barrels, and have a cap bank for each of the barrels, you could have it fire all at once or in rapid sucession.
Anyways this is an amazing cap bank and your works is looking great
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Thu Jun 26 2008, 05:19PM
Yes, a single shot is the plan because I'm building induction launchers....I'm going to build a gigantic 1 foot+ pancake coil and launch some seriously huge objects, and hopefully get some larger "rockets" flying.
All these caps appear to be matched, and charge relatively evenly, so external balancing wasn't necessary.
FastMHz, Thu Jun 26 2008, 05:19PM
Yes, a single shot is the plan because I'm building induction launchers....I'm going to build a gigantic 1 foot+ pancake coil and launch some seriously huge objects, and hopefully get some larger "rockets" flying.
All these caps appear to be matched, and charge relatively evenly, so external balancing wasn't necessary.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Dr. SSTC, Thu Jul 10 2008, 04:59AM
im just wondering if you discharged that bank fully charged into me would i expolde
Dr. SSTC, Thu Jul 10 2008, 04:59AM
im just wondering if you discharged that bank fully charged into me would i expolde
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Myke, Thu Jul 10 2008, 05:23AM
EDIT: Ok, you probably would die though...
Myke, Thu Jul 10 2008, 05:23AM
jovica93 wrote ...
im just wondering if you discharged that bank fully charged into me would i expolde
Weird question but yeah... probably some part or all of you would explode.im just wondering if you discharged that bank fully charged into me would i expolde
EDIT: Ok, you probably would die though...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Tesladownunder, Thu Jul 10 2008, 05:48AM
Yes and no.
Evenly distributed the energy would probably only raise your body temperature by a few degrees at a guess. It is only one 2kW electric kettle for 12 seconds after all.
I have tried to explode a sausage with 4kJ with almost no effect at all.
On the other hand if you arrange a high temperature spark inside the sausage like exploding a wire, then the explosive effect will be very destructive without much heating. This is how to blow up a watermelon or similar.
TDU
Tesladownunder, Thu Jul 10 2008, 05:48AM
Yes and no.
Evenly distributed the energy would probably only raise your body temperature by a few degrees at a guess. It is only one 2kW electric kettle for 12 seconds after all.
I have tried to explode a sausage with 4kJ with almost no effect at all.
On the other hand if you arrange a high temperature spark inside the sausage like exploding a wire, then the explosive effect will be very destructive without much heating. This is how to blow up a watermelon or similar.
TDU
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Marko, Thu Jul 10 2008, 12:51PM
Yeah, exploding body parts is pretty much a myth unless you are really going to thrust a wire through yourself. :P
Remember that it takes 4kJ to raise the temperature of 1kg of water for only 1K! Then there is the very high enthalpy of vaporisation: 2.2kJ/g
So if you touch the output of that bank, really the only serious danger would be electric shock, and some rather small burns (compare to TDU's hotdog.)
Marko
Marko, Thu Jul 10 2008, 12:51PM
Yeah, exploding body parts is pretty much a myth unless you are really going to thrust a wire through yourself. :P
Remember that it takes 4kJ to raise the temperature of 1kg of water for only 1K! Then there is the very high enthalpy of vaporisation: 2.2kJ/g
So if you touch the output of that bank, really the only serious danger would be electric shock, and some rather small burns (compare to TDU's hotdog.)
Marko
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Dr. SSTC, Thu Jul 10 2008, 10:49PM
well thank for explaining that guys i was just thinking thet because i saw water melons being exploded by much smaller banks
Dr. SSTC, Thu Jul 10 2008, 10:49PM
well thank for explaining that guys i was just thinking thet because i saw water melons being exploded by much smaller banks
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Andyman, Fri Jul 11 2008, 02:43AM
I'm wondering if it would be at all possible to recycle the energy from the magnetic field at all? If you had several small coils arranged around the big coil to be induced with the large magnetic field of the discharge and somehow store the induced current for the next shot. I know it wouldn't be a LOT of energy recycled but would it be at all possible?
Andyman, Fri Jul 11 2008, 02:43AM
I'm wondering if it would be at all possible to recycle the energy from the magnetic field at all? If you had several small coils arranged around the big coil to be induced with the large magnetic field of the discharge and somehow store the induced current for the next shot. I know it wouldn't be a LOT of energy recycled but would it be at all possible?
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Fri Jul 11 2008, 09:55PM
Guys - this bank *would* blow parts of you or various objects apart...check my latest video out to see what happens to a potato and pickles, and other things:
http://www.youtube.com/watch?v=UAgfGGjsoQM
I did not put a wire through that potato (the one that detonates in a shower of sparks and flame)
FastMHz, Fri Jul 11 2008, 09:55PM
Guys - this bank *would* blow parts of you or various objects apart...check my latest video out to see what happens to a potato and pickles, and other things:
http://www.youtube.com/watch?v=UAgfGGjsoQM
I did not put a wire through that potato (the one that detonates in a shower of sparks and flame)
Re: [moved] 24,000j Capacitor Bank (Now Complete)
aonomus, Sat Jul 12 2008, 03:52AM
Jeez. Girly laughs all around. Did you seriously blow up 10 or so neon tubes??
And on all the other discharges, those are gunshots practically, I hope the neighbors didn't mind.... maybe try making a ETG?
aonomus, Sat Jul 12 2008, 03:52AM
Jeez. Girly laughs all around. Did you seriously blow up 10 or so neon tubes??
And on all the other discharges, those are gunshots practically, I hope the neighbors didn't mind.... maybe try making a ETG?
Re: [moved] 24,000j Capacitor Bank (Now Complete)
GeordieBoy, Sat Jul 12 2008, 11:48AM
Looking at that picture...
it doesnt look like you have any insulation between the cans of the capacitors. If all metal cans are touching then the "internals-to-can" voltage on the left-most and right-most banks of capacitors is going to be very high. You mentioned charging the bank to over 4000 volts. I doubt that the metal can insulation is specified up to this kind of voltage for standard 450 volt electrolytics. Some supplementary insulation is probably advisable since any end-to-end breakdown is going to dump the stored energy of the entire bank into the weakest point... Most likely with vapourised electrolyte and quite spectacular results.
I'd also second the comments made early about electrolytics and reverse voltage, and the importance of balancing resistors. Electrolytics being subject to this abuse will not last long, and when they start to fail the leakage currents for individual components may start to vary a lot.
-Richie,
GeordieBoy, Sat Jul 12 2008, 11:48AM
Looking at that picture...
it doesnt look like you have any insulation between the cans of the capacitors. If all metal cans are touching then the "internals-to-can" voltage on the left-most and right-most banks of capacitors is going to be very high. You mentioned charging the bank to over 4000 volts. I doubt that the metal can insulation is specified up to this kind of voltage for standard 450 volt electrolytics. Some supplementary insulation is probably advisable since any end-to-end breakdown is going to dump the stored energy of the entire bank into the weakest point... Most likely with vapourised electrolyte and quite spectacular results.
I'd also second the comments made early about electrolytics and reverse voltage, and the importance of balancing resistors. Electrolytics being subject to this abuse will not last long, and when they start to fail the leakage currents for individual components may start to vary a lot.
-Richie,
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sat Jul 12 2008, 05:29PM
haha yeah I laugh quiet energetically....huge amounts of electricity make me really happy!
Anyway the cans of each cap are not touching, there's a 1/8" airgap between every one. I do plan to add some insulation between each string though, as it wouldn't be hard and is extra insurance.
I was building ETCs for use with my 3.5kj system with success, but even at only 3.5kj the guns were exploding. I'd need some seriously well machined barrels to make one that'd withstand 24kj. I'm most eager to get my 1foot+ diameter pancake coil done.
FastMHz, Sat Jul 12 2008, 05:29PM
haha yeah I laugh quiet energetically....huge amounts of electricity make me really happy!
Anyway the cans of each cap are not touching, there's a 1/8" airgap between every one. I do plan to add some insulation between each string though, as it wouldn't be hard and is extra insurance.
I was building ETCs for use with my 3.5kj system with success, but even at only 3.5kj the guns were exploding. I'd need some seriously well machined barrels to make one that'd withstand 24kj. I'm most eager to get my 1foot+ diameter pancake coil done.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Arcstarter, Sat Jul 12 2008, 09:43PM
This is one bad @&$ project! Wow, 24 freaking kilojoules is funner that i thought! I cannot wait to see your pancake coil launching 50 pound sandbags through the atmosphere :P. Maybe that was just a tiny bit over exaggerated. But it would be cool to see you put such a force on a disk it basically explodes when it hits something :).
Arcstarter, Sat Jul 12 2008, 09:43PM
This is one bad @&$ project! Wow, 24 freaking kilojoules is funner that i thought! I cannot wait to see your pancake coil launching 50 pound sandbags through the atmosphere :P. Maybe that was just a tiny bit over exaggerated. But it would be cool to see you put such a force on a disk it basically explodes when it hits something :).
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sun Jul 13 2008, 08:56PM
Funny is an understatement...I rarely laugh that hard at something, except maybe a standup routine on HBO....but this was more of a test of the system than what I built it for, which is to launch things, big things, really fast and high, using induction coils.
FastMHz, Sun Jul 13 2008, 08:56PM
Funny is an understatement...I rarely laugh that hard at something, except maybe a standup routine on HBO....but this was more of a test of the system than what I built it for, which is to launch things, big things, really fast and high, using induction coils.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Mon Aug 04 2008, 05:05PM
I've been dabbling in coin (and other object) shrinking. Unfortunately repeated 20kj+ discharges have vaporized the screw holding the left knob in the spark gap...it just fell off, and needs repairs.
FastMHz, Mon Aug 04 2008, 05:05PM
I've been dabbling in coin (and other object) shrinking. Unfortunately repeated 20kj+ discharges have vaporized the screw holding the left knob in the spark gap...it just fell off, and needs repairs.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Tesladownunder, Mon Aug 04 2008, 06:08PM
I would be surprised if you got good results with coin shrinking. The rate of current rise will be very slow with electrolytics.
Here is what I get at 5kJ with a 1 yen coin.
TDU
Tesladownunder, Mon Aug 04 2008, 06:08PM
I would be surprised if you got good results with coin shrinking. The rate of current rise will be very slow with electrolytics.
Here is what I get at 5kJ with a 1 yen coin.
TDU
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Ken M., Mon Aug 04 2008, 09:08PM
What a waste of 1 good yen..BTw whats 1yen worth in Aussy cash?
Ken M., Mon Aug 04 2008, 09:08PM
What a waste of 1 good yen..BTw whats 1yen worth in Aussy cash?
Re: [moved] 24,000j Capacitor Bank (Now Complete)
rp181, Tue Aug 05 2008, 12:42AM
from google:
1 Japanese yen = 0.009248 U.S. dollars
i dont know what "aussy cash" is =)
rp181, Tue Aug 05 2008, 12:42AM
from google:
1 Japanese yen = 0.009248 U.S. dollars
i dont know what "aussy cash" is =)
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Aug 06 2008, 03:51AM
That looks like it shrunk a LOT at 5kj....why wouldn't I get even smaller with upwards of 24kj?
FastMHz, Wed Aug 06 2008, 03:51AM
That looks like it shrunk a LOT at 5kj....why wouldn't I get even smaller with upwards of 24kj?
Tesladownunder wrote ...
I would be surprised if you got good results with coin shrinking. The rate of current rise will be very slow with electrolytics.
Here is what I get at 5kJ with a 1 yen coin.
TDU
I would be surprised if you got good results with coin shrinking. The rate of current rise will be very slow with electrolytics.
Here is what I get at 5kJ with a 1 yen coin.
TDU
Re: [moved] 24,000j Capacitor Bank (Now Complete)
EEYORE, Wed Aug 06 2008, 06:24AM
Your peak current will not be as high with those lytics as it is with pulse caps.
matt
EEYORE, Wed Aug 06 2008, 06:24AM
Your peak current will not be as high with those lytics as it is with pulse caps.
matt
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Electroholic, Wed Aug 06 2008, 07:16AM
need more di/dt.
also the japanese coin is made of Alu.
Electroholic, Wed Aug 06 2008, 07:16AM
need more di/dt.
also the japanese coin is made of Alu.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Ken M., Thu Aug 07 2008, 12:41AM
3 yen= .05 in Austrailian currency
Ken M., Thu Aug 07 2008, 12:41AM
3 yen= .05 in Austrailian currency
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sat Sept 13 2008, 05:32PM
I have built a new spark gap, and the system is now back in action!!
I've also built what I've intended to use this massive bank for in the first place - a giant pancake coil. The actual coil is 11" in diameter and 1/4" thick, made with flat wire. I used the same technique to make this one as I did for my smaller ones, it just made me sweat a lot more pulling that thick wire.
I've also added supports to the bank so that I can move half of it at a time, making it much more portable. I can load it into the back of my pickup and do experiments in a field now.
I should be able to send some rather large chunks of aluminum flying with this one. I'm going to attach a supportive base and some connectors and begin testing at lower energies soon.
FastMHz, Sat Sept 13 2008, 05:32PM
I have built a new spark gap, and the system is now back in action!!
I've also built what I've intended to use this massive bank for in the first place - a giant pancake coil. The actual coil is 11" in diameter and 1/4" thick, made with flat wire. I used the same technique to make this one as I did for my smaller ones, it just made me sweat a lot more pulling that thick wire.
I've also added supports to the bank so that I can move half of it at a time, making it much more portable. I can load it into the back of my pickup and do experiments in a field now.
I should be able to send some rather large chunks of aluminum flying with this one. I'm going to attach a supportive base and some connectors and begin testing at lower energies soon.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sun Sept 14 2008, 04:50PM
I have tested the new coil, and am astounded at what I saw. At only 300j, which is 500v in my bank, a 3 foot by 1 foot, 1/8" thick sheet of aluminum flew half way up to the garage ceiling!!!
Here's the coil (Pic Link)!!
FastMHz, Sun Sept 14 2008, 04:50PM
I have tested the new coil, and am astounded at what I saw. At only 300j, which is 500v in my bank, a 3 foot by 1 foot, 1/8" thick sheet of aluminum flew half way up to the garage ceiling!!!
Here's the coil (Pic Link)!!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Neil, Mon Sept 15 2008, 10:28AM
When do you try all 24,000 joule through it
Might be worth trying that outside...
Neil, Mon Sept 15 2008, 10:28AM
When do you try all 24,000 joule through it
Might be worth trying that outside...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Tue Sept 16 2008, 08:24PM
That will happen out in a field somewhere....'cause when a sheet of metal goes up.....yeah......I'm already getting 1/4" thick 1footx1foot plates of aluminum across the garage on less than 500j.
I want to calculate the efficiencies when I send one up, and create charts and graphs like I did with my 3.5kj launchers last year, where I repeatedly reached 10%.
FastMHz, Tue Sept 16 2008, 08:24PM
That will happen out in a field somewhere....'cause when a sheet of metal goes up.....yeah......I'm already getting 1/4" thick 1footx1foot plates of aluminum across the garage on less than 500j.
I want to calculate the efficiencies when I send one up, and create charts and graphs like I did with my 3.5kj launchers last year, where I repeatedly reached 10%.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
notafakeninja, Wed Sept 17 2008, 01:43PM
Well, its awsome, I'm just wondering where he got those...and if he ordered them or got them for free. Yep, and all you gotta do is be careful, and hope that a blast won't happen.
notafakeninja, Wed Sept 17 2008, 01:43PM
Well, its awsome, I'm just wondering where he got those...and if he ordered them or got them for free. Yep, and all you gotta do is be careful, and hope that a blast won't happen.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
aonomus, Sat Sept 20 2008, 08:05PM
Featured on hackaday:
aonomus, Sat Sept 20 2008, 08:05PM
Featured on hackaday:
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Dragon64, Sun Sept 21 2008, 12:38AM
Look at some of the comments for it.
Dragon64, Sun Sept 21 2008, 12:38AM
aonomus wrote ...
Featured on hackaday:
Featured on hackaday:
Look at some of the comments for it.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Firefox, Sun Sept 21 2008, 01:02AM
Doh.
Sheesh, just because people can't see it, it seems a good deal of people can't understand Electromagnetism. Apparently Tesla's inventions are magical as well.
In any case, looking great. I can't wait to see a 6" diameter rocket being booted skyward by a 24kJ electromagnetic pulse. It looks like it might be a great way to launch larger rockets without a LEUP!
I've been toying with the idea of building some Alpha sized induction rocket launchers to toy around with in the back yard. I might try some air-started motors as well, for some extra fun, thanks for inspiration, FastMHz.
Firefox, Sun Sept 21 2008, 01:02AM
Doh.
Sheesh, just because people can't see it, it seems a good deal of people can't understand Electromagnetism. Apparently Tesla's inventions are magical as well.In any case, looking great. I can't wait to see a 6" diameter rocket being booted skyward by a 24kJ electromagnetic pulse. It looks like it might be a great way to launch larger rockets without a LEUP!
I've been toying with the idea of building some Alpha sized induction rocket launchers to toy around with in the back yard. I might try some air-started motors as well, for some extra fun, thanks for inspiration, FastMHz.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Tue Apr 21 2009, 07:25PM
HI EVERYONE!! I'm still alive, and better than ever. Now that the weather has warmed up, I'm beginning to bring out the big launchers again.
As it stands, I have my large pancake coil (~ 11" diameter) ready to go. My "rockets" of the moment are 5gal buckets with a 1/4" thick slab of aluminum mounted to the bottom. A 12kj pulse the other day sent this >2kg projectile skyward, and it went so high it appeared about the size of the moon. After a few launches, the bucket was destroyed.
I now have a new one, with a better mounted plate, and somewhat of a cone shaped top. I will be launching this soon, and taking video of the action. I hope to get some rough calculations of efficiency going onward.
FastMHz, Tue Apr 21 2009, 07:25PM
HI EVERYONE!! I'm still alive, and better than ever. Now that the weather has warmed up, I'm beginning to bring out the big launchers again.
As it stands, I have my large pancake coil (~ 11" diameter) ready to go. My "rockets" of the moment are 5gal buckets with a 1/4" thick slab of aluminum mounted to the bottom. A 12kj pulse the other day sent this >2kg projectile skyward, and it went so high it appeared about the size of the moon. After a few launches, the bucket was destroyed.
I now have a new one, with a better mounted plate, and somewhat of a cone shaped top. I will be launching this soon, and taking video of the action. I hope to get some rough calculations of efficiency going onward.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
aonomus, Wed Apr 22 2009, 03:09AM
Damn, we haven't heard from you in so long didn't know if you were still alive...
Out of curiosity, have you ever tried launching stuff horizontally mounted on a rail or otherwise? Imagine a magnetically launched cart or something...
aonomus, Wed Apr 22 2009, 03:09AM
Damn, we haven't heard from you in so long didn't know if you were still alive...
Out of curiosity, have you ever tried launching stuff horizontally mounted on a rail or otherwise? Imagine a magnetically launched cart or something...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Apr 22 2009, 04:36AM
Yes! I shot a pale across a field, but it's usually hard to contain the forces. Whatever the coil is against, gets destroyed.
FastMHz, Wed Apr 22 2009, 04:36AM
Yes! I shot a pale across a field, but it's usually hard to contain the forces. Whatever the coil is against, gets destroyed.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
aonomus, Wed Apr 22 2009, 06:32AM
Thats why I meant more a reinforced metal plate mounted against a cart on wheels, with the coil solidly in place so all the energy goes into acceleration... would be an interesting thing to see something go from 0 to reallyreallyfast instantly....
Or it could be a bust and cause little momentum change, being anticlimactic.
aonomus, Wed Apr 22 2009, 06:32AM
Thats why I meant more a reinforced metal plate mounted against a cart on wheels, with the coil solidly in place so all the energy goes into acceleration... would be an interesting thing to see something go from 0 to reallyreallyfast instantly....
Or it could be a bust and cause little momentum change, being anticlimactic.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Plasma Lover, Wed Apr 22 2009, 03:21PM
Half of the energy would go into acceleration of the work coil, pushing it backwards, along with the cart. Then there's the eddy currents induced in the plate you suggested behind the work coil, which would cause the work coil to -
A: Fly apart, starting in the center or the outer edge, then having less force in the opposite part of the coil because of DC resistance.
B: Fly apart because it goes flying off of the metal plate and gets hammered into the ground at 20'/s
C: Push the cart back, because of its wheels. Possibly pushing the cart over.
It's obvious which is the most desirable. Of course, the other two may be more fun...
Plasma Lover, Wed Apr 22 2009, 03:21PM
aonomus wrote ...
Thats why I meant more a reinforced metal plate mounted against a cart on wheels, with the coil solidly in place so all the energy goes into acceleration...
Thats why I meant more a reinforced metal plate mounted against a cart on wheels, with the coil solidly in place so all the energy goes into acceleration...
Half of the energy would go into acceleration of the work coil, pushing it backwards, along with the cart. Then there's the eddy currents induced in the plate you suggested behind the work coil, which would cause the work coil to -
A: Fly apart, starting in the center or the outer edge, then having less force in the opposite part of the coil because of DC resistance.
B: Fly apart because it goes flying off of the metal plate and gets hammered into the ground at 20'/s
C: Push the cart back, because of its wheels. Possibly pushing the cart over.
It's obvious which is the most desirable. Of course, the other two may be more fun...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
aonomus, Wed Apr 22 2009, 06:01PM
Well I meant more along the lines of strapping the coil to a solid object that is bolted into the ground...
Exploding work coil right behind your butt sounds fun though.....
aonomus, Wed Apr 22 2009, 06:01PM
Well I meant more along the lines of strapping the coil to a solid object that is bolted into the ground...
Exploding work coil right behind your butt sounds fun though.....
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Apr 22 2009, 07:33PM
It'd be rather neat if I could get a *low cost* accelerometer to see what these things are doing in that area...know of any? I've seen Mythbusters use those packing sensors that break...
FastMHz, Wed Apr 22 2009, 07:33PM
It'd be rather neat if I could get a *low cost* accelerometer to see what these things are doing in that area...know of any? I've seen Mythbusters use those packing sensors that break...
Re: [moved] 24,000j Capacitor Bank (Now Complete)
EEYORE, Wed Apr 22 2009, 07:39PM
Im surprised these capacitors have lasted so long. How many discharges would you estimate have been done to them?
Matt
EEYORE, Wed Apr 22 2009, 07:39PM
Im surprised these capacitors have lasted so long. How many discharges would you estimate have been done to them?
Matt
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Apr 22 2009, 07:46PM
Probably nearing a couple hundred...I did have 2 individual failures that required replacement. Closer inspection revealed they were of different contstruction, and therefore, were unmatched to the rest of the bank.
ed: I fully expect the system to slowly self destruct...and I'll run it into the ground. At that time, I'll look for HV pulse caps of similar capacity
FastMHz, Wed Apr 22 2009, 07:46PM
Probably nearing a couple hundred...I did have 2 individual failures that required replacement. Closer inspection revealed they were of different contstruction, and therefore, were unmatched to the rest of the bank.
ed: I fully expect the system to slowly self destruct...and I'll run it into the ground. At that time, I'll look for HV pulse caps of similar capacity
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Renesis, Wed Apr 22 2009, 08:18PM
I would like to see this coil placed inside a sturdy, low box of half an inch steel plates welded together, just to see what kind of dents it would make. Mechanically bending such thick plates take a lot of force.
Renesis, Wed Apr 22 2009, 08:18PM
I would like to see this coil placed inside a sturdy, low box of half an inch steel plates welded together, just to see what kind of dents it would make. Mechanically bending such thick plates take a lot of force.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
hotcrazyfruit, Thu Apr 23 2009, 12:53AM
OMG wow thats insane, i thought my 5kj bank was huge.. lol. i think you should try making a large rail gun. ov course after your coil gun. but i think both will do VERY well with 24 kilojoules, and mouser sells 44500 amp 8.3ms SCR's, at 600volts. dunno if that helps, i could PM you other sources ,if need be.
hotcrazyfruit, Thu Apr 23 2009, 12:53AM
OMG wow thats insane, i thought my 5kj bank was huge.. lol. i think you should try making a large rail gun. ov course after your coil gun. but i think both will do VERY well with 24 kilojoules, and mouser sells 44500 amp 8.3ms SCR's, at 600volts. dunno if that helps, i could PM you other sources ,if need be.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Fraggle, Thu Apr 23 2009, 08:21AM
A railgun with all those caps in parallel would be staggering.
Fraggle, Thu Apr 23 2009, 08:21AM
A railgun with all those caps in parallel would be staggering.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Hon1nbo, Fri Apr 24 2009, 01:17AM
you can buy the actual accelerometers from a place like Spark Fun
or you could use a Wii Controller and a Bluetooth connection
my curiosity is if these types of sensors will be affected by the pulse generated without having to use annoying EM shielding... which would likely have to include the power to such sensitive devices...
personally, I use my High Speed Camera for that kind of stuff... but $500 isn't "low cost" for most people... I had to wait years for one.
Hon1nbo, Fri Apr 24 2009, 01:17AM
FastMHz wrote ...
It'd be rather neat if I could get a *low cost* accelerometer to see what these things are doing in that area...know of any? I've seen Mythbusters use those packing sensors that break...
It'd be rather neat if I could get a *low cost* accelerometer to see what these things are doing in that area...know of any? I've seen Mythbusters use those packing sensors that break...
you can buy the actual accelerometers from a place like Spark Fun
or you could use a Wii Controller and a Bluetooth connection
my curiosity is if these types of sensors will be affected by the pulse generated without having to use annoying EM shielding... which would likely have to include the power to such sensitive devices...
personally, I use my High Speed Camera for that kind of stuff... but $500 isn't "low cost" for most people... I had to wait years for one.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
rp181, Fri Apr 24 2009, 01:38AM
Those are called "shockwatch", google it. They have a variety of levels.I have a accelerameter, 3 axis 5G, it is about a 1" square PCB. It uses a I2C interface, if you can do that, i will be happy to point you where you can get one.
rp181, Fri Apr 24 2009, 01:38AM
Those are called "shockwatch", google it. They have a variety of levels.I have a accelerameter, 3 axis 5G, it is about a 1" square PCB. It uses a I2C interface, if you can do that, i will be happy to point you where you can get one.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Tesladownunder, Fri Apr 24 2009, 02:09AM
Silicon based accelerometers running to 5g wont do it. The forces are acting only over a few cm and must be in the order of well over 20G. Hard to measure as metal will deform at these forces and reduce the acceleration.
Simplest to measure kinetic energy gained is to use a variant of the ballistic pendulum. Basically see how high it flies and do the simple physics. If it is a light object like a drink can and air friction is an issue, fire it into a heavy padded object that will catch it and see how high that goes (momentum is conserved).
Secondly, I am still concerned about cap failure. I bet you didn't fail with 24kJ charged. Probably cap failed on the reverse ringdown when a lot of the energy is gone then was short when charging was attempted so didn't reaccumulate.
24kJ into single cap = b o m b
Tesladownunder, Fri Apr 24 2009, 02:09AM
FastMHz wrote ...
It'd be rather neat if I could get a *low cost* accelerometer
It'd be rather neat if I could get a *low cost* accelerometer
Silicon based accelerometers running to 5g wont do it. The forces are acting only over a few cm and must be in the order of well over 20G. Hard to measure as metal will deform at these forces and reduce the acceleration.
Simplest to measure kinetic energy gained is to use a variant of the ballistic pendulum. Basically see how high it flies and do the simple physics. If it is a light object like a drink can and air friction is an issue, fire it into a heavy padded object that will catch it and see how high that goes (momentum is conserved).
Secondly, I am still concerned about cap failure. I bet you didn't fail with 24kJ charged. Probably cap failed on the reverse ringdown when a lot of the energy is gone then was short when charging was attempted so didn't reaccumulate.
24kJ into single cap = b o m b
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Fri Apr 24 2009, 04:34AM
Actually, failure occured during charge....what a surprise that was, blew through the lexan cover and all.
Not sure that any electronic accelerometer would survive these forces, or the EMP. I think the 'ShockWatch' may be my answer...or video analysis. I should get Discovery's TimeWarp to do a segment on my launchers!!
FastMHz, Fri Apr 24 2009, 04:34AM
Actually, failure occured during charge....what a surprise that was, blew through the lexan cover and all.
Not sure that any electronic accelerometer would survive these forces, or the EMP. I think the 'ShockWatch' may be my answer...or video analysis. I should get Discovery's TimeWarp to do a segment on my launchers!!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Finn Hammer, Fri Apr 24 2009, 04:59AM
I launch 4" dia. by 3/4 inch thick aluminum slugs with it.
They fly 20 meters into the air. Haven't measured it, but I estimate like that.
Thick discs is the key to high flying objects, in my opinion.
Cheers, Finn Hammer
Finn Hammer, Fri Apr 24 2009, 04:59AM
FastMHz wrote ...
Actually, failure occured during charge....what a surprise that was, blew through the lexan cover and all.
Not sure that any electronic accelerometer would survive these forces, or the EMP. I think the 'ShockWatch' may be my answer...or video analysis. I should get Discovery's TimeWarp to do a segment on my launchers!!
I have a 2kJ disk launcher.Actually, failure occured during charge....what a surprise that was, blew through the lexan cover and all.
Not sure that any electronic accelerometer would survive these forces, or the EMP. I think the 'ShockWatch' may be my answer...or video analysis. I should get Discovery's TimeWarp to do a segment on my launchers!!
I launch 4" dia. by 3/4 inch thick aluminum slugs with it.
They fly 20 meters into the air. Haven't measured it, but I estimate like that.
Thick discs is the key to high flying objects, in my opinion.
Cheers, Finn Hammer
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Fri Apr 24 2009, 08:54PM
I found that as well, thicker seems to work better than thinner....the only problem is thicker ones come down harder too :-o I have 1/4" on my bucket, a 11" diameter 1/2" platter might weigh so much that it'd cancel out the gains...if only I had a chunk of aluminum that big to try.
FastMHz, Fri Apr 24 2009, 08:54PM
I found that as well, thicker seems to work better than thinner....the only problem is thicker ones come down harder too :-o I have 1/4" on my bucket, a 11" diameter 1/2" platter might weigh so much that it'd cancel out the gains...if only I had a chunk of aluminum that big to try.
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Tesladownunder, Tue Aug 11 2009, 12:37PM
Is there any more news on the launcher. Caps still functioning? Things launched etc
Tesladownunder, Tue Aug 11 2009, 12:37PM
Is there any more news on the launcher. Caps still functioning? Things launched etc
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Fri Dec 25 2009, 06:13PM
Yes, the system is still operational! I have yet to launch the bucket from the giant coil as other things have taken priority, but it will happen! On the other hand, the bank has been utilized for purely entertainment purposes a few times as can be seen in my YouTube videos. Regards
FastMHz, Fri Dec 25 2009, 06:13PM
Yes, the system is still operational! I have yet to launch the bucket from the giant coil as other things have taken priority, but it will happen! On the other hand, the bank has been utilized for purely entertainment purposes a few times as can be seen in my YouTube videos. Regards
Re: [moved] 24,000j Capacitor Bank (Now Complete)
teravolt, Mon Dec 28 2009, 08:21AM
nice work FastMHz, I am surprized that the caps haven't shorted between the cans yet. I wanted to try this expieriment but using 6 scrs with 6 banks in seqence but I got nevice because if 1 bank fails the others will dump into that one bank. are you using gradeing resistors? can you poast a link to your youtube vid. thanks NB
teravolt, Mon Dec 28 2009, 08:21AM
nice work FastMHz, I am surprized that the caps haven't shorted between the cans yet. I wanted to try this expieriment but using 6 scrs with 6 banks in seqence but I got nevice because if 1 bank fails the others will dump into that one bank. are you using gradeing resistors? can you poast a link to your youtube vid. thanks NB
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Mon Dec 28 2009, 06:19PM
All my videos can be found here:
http://www.youtube.com/fastmhz
And technical information is on my blog:
http://www.fastmhz.com
Hope everyone had a spectacular holiday!!
FastMHz, Mon Dec 28 2009, 06:19PM
All my videos can be found here:
http://www.youtube.com/fastmhz
And technical information is on my blog:
http://www.fastmhz.com
Hope everyone had a spectacular holiday!!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
RogerInOhio, Wed Dec 30 2009, 02:05AM
Hi Ceyn, I love your pancake coils. That is really a neat way to launch things. One thing I was wondering about though is if you discharge your capacitor bank into an inductive load doesn't the thing oscillate causing the capacitors to get charged in the revers polarity and wouldn't that be bad if they are electrolytic capacitors?
One more question. Have you noticed if the conductivity of the disk being launched makes much difference in how high it goes ? There is a good demo at the end of this video where a washer is cooled with liquid nitrogen before launching and it seems to help a lot.
Roger
RogerInOhio, Wed Dec 30 2009, 02:05AM
Hi Ceyn, I love your pancake coils. That is really a neat way to launch things. One thing I was wondering about though is if you discharge your capacitor bank into an inductive load doesn't the thing oscillate causing the capacitors to get charged in the revers polarity and wouldn't that be bad if they are electrolytic capacitors?
One more question. Have you noticed if the conductivity of the disk being launched makes much difference in how high it goes ? There is a good demo at the end of this video
where a washer is cooled with liquid nitrogen before launching and it seems to help a lot.Roger
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Wed Dec 30 2009, 04:22AM
I'm sure it does ring my caps, but I don't seem to be having a problem. The bank hasn't seemed to have weakened despite hundreds of pulses into coils and other objects.
I'm sure a super-conductive disc would be better, however there is also the issue of this amount of energy deforming them - a super-cooled disc might explode or at least crack. It'd be worth trying if I could get my hands on some liquid nitrogen!
FastMHz, Wed Dec 30 2009, 04:22AM
I'm sure it does ring my caps, but I don't seem to be having a problem. The bank hasn't seemed to have weakened despite hundreds of pulses into coils and other objects.
I'm sure a super-conductive disc would be better, however there is also the issue of this amount of energy deforming them - a super-cooled disc might explode or at least crack. It'd be worth trying if I could get my hands on some liquid nitrogen!
Re: [moved] 24,000j Capacitor Bank (Now Complete)
FastMHz, Sat Oct 01 2011, 12:04AM
OK so it's been a couple of years since I've done anything with this setup. Having an amazing girlfriend, then fiancee, then getting handfasted on the 10th of this month have distracted me a little bit
But the garage is once again largely clear and *something* might finally happen soon...stay tuned
FastMHz, Sat Oct 01 2011, 12:04AM
OK so it's been a couple of years since I've done anything with this setup. Having an amazing girlfriend, then fiancee, then getting handfasted on the 10th of this month have distracted me a little bit
But the garage is once again largely clear and *something* might finally happen soon...stay tuned
Re: [moved] 24,000j Capacitor Bank (Now Complete)
Finn Hammer, Sun Oct 02 2011, 08:04PM
Wonderfull, Wonderfull, Wonderfull !
♥♥♥♥♥Love Rules♥♥♥♥♥
Cheers, Finn Hammer
Finn Hammer, Sun Oct 02 2011, 08:04PM
Wonderfull, Wonderfull, Wonderfull !
♥♥♥♥♥Love Rules♥♥♥♥♥
Cheers, Finn Hammer
Re: [moved] 24,000j Capacitor Bank (Now Complete)
StevenCaton, Mon Oct 03 2011, 05:45PM
StevenCaton, Mon Oct 03 2011, 05:45PM
Wonderfull, Wonderfull, Wonderfull !
♥♥♥♥♥Love Rules♥♥♥♥♥
Cheers, Finn Hammer
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