Capacitor bank/can crusher...
Nicko, Thu Oct 14 2010, 09:57PMStarting point (some bits missing):
Final config can be 8800uF @ 500V (1100J) or 4400uF @ 1000V (2200J) using 2200uF @ 500V PEH169 series caps. I also have a load of PEH200 series 3300uF @ 500v which give 1650J & 3300J respectively, but these will probably destroy my thyristors
. All caps used are re-formed first in 50V stages up to the full 500V over a period of about 3 hours each.Schematic:
]washer launcher V1.pdf[/file]
NOTE: When used at the Cambridge Teslathon 2010, a Marx Generator on the adjacent table caused enough interference to make the bank trigger unexpectedly. Be VERY careful when charging a bank like this - expect the unexpected! Do NOT operate it in the presence of large amounts of interference.
Fully safety interlocked with charging disconnect during firing & automatic discharging if power fails etc. Handles up to two paralleled bricks with GDT drive. The circuit I drew up didn't seem to be too complicated but there sure seem to be a lot of wires in there... Built on an old shelf with some rubber feet underneath. Small xfrmr is 12-0-12 for logic, lights & contactors; large xfrmr is a step-up from 230 -> 360VAC for charging and to isolate the HT side. Stripboard has the fire button trigger & timing for the contactors, GDT drive and interlock control.
I'm using 4AWG cables mainly as I cannot bend or crimp the 0/1 AWG cables I have - all these jumpers are from the salvage of the kit in the link above. To be honest, 4AWG is a complete bas*ard to work with too...
Mostly complete - testing in progress with 3 out of 8 caps (all 2200uF @ 500V 17 milliohm ESR, i.e. bank ESR of about 4 milliohms) running at only 120VDC (about 50J) whilst I check the currents etc. Logic & interlocking seems to work fine... except for small annoyance - when its turned off, it trips the thyristor one last time - annoying...
Meter reads 0-100V for actual 0-1000V
Just testing one of the bricks with only 3 caps installed...
Launch pad (after being glued back together) - subsequently, the launch pad ripped itself apart - a new epoxy-potted one is needed. About 15 turns of 2.5mm diam Cu sandwiched between two 4mm acrylic discs. Choke is 2mH @ huge amps (wound with thick Cu strips, 4mmx6mm x-section)
Measuring the firing pulse...
Cheers
Re: Capacitor bank/can crusher...
dmg, Thu Oct 14 2010, 11:04PM
Nice parts! especially those sexy RIFAs.
What ratings are those bricks? (white ones, eupec/semikron?)
dmg, Thu Oct 14 2010, 11:04PM
Nice parts! especially those sexy RIFAs.
What ratings are those bricks? (white ones, eupec/semikron?)
Re: Capacitor bank/can crusher...
teravolt, Fri Oct 15 2010, 02:32AM
are any of those parts decoys, looks like a giant variable dc power supply.
teravolt, Fri Oct 15 2010, 02:32AM
are any of those parts decoys, looks like a giant variable dc power supply.
Re: Capacitor bank/can crusher...
Nicko, Fri Oct 15 2010, 04:12AM
Most caps are 2200Uf @ 500vdc but I have a large batch of 3300uF @ 500VDC as well... all are IEC 60384 defined "long life" types and unused...
There are several "bricks" of increasing sizes as I expect to detonate a few - they are thyristors and start at 1800A peak one cycle up to the biggest at 6700A. The small stripboard is just a few timers to get the contactor interlocking sequences right - the gate drive is missing from it in the photo - the bigger bricks need a hefty gate drive current.
There is a strong hint hidden in the photo (not that its isn't pretty obvious anyway).
Cheers
Nicko, Fri Oct 15 2010, 04:12AM
teravolt wrote ...
are any of those parts decoys, looks like a giant variable dc power supply.
No decoys - Its actually not complex - there are a few bits missing from the photo - mostly Cu busbars and big heavy cables - they come from some stuff intercepted before the WEEE bin... are any of those parts decoys, looks like a giant variable dc power supply.
Most caps are 2200Uf @ 500vdc but I have a large batch of 3300uF @ 500VDC as well... all are IEC 60384 defined "long life" types and unused...There are several "bricks" of increasing sizes as I expect to detonate a few - they are thyristors and start at 1800A peak one cycle up to the biggest at 6700A. The small stripboard is just a few timers to get the contactor interlocking sequences right - the gate drive is missing from it in the photo - the bigger bricks need a hefty gate drive current.
There is a strong hint hidden in the photo (not that its isn't pretty obvious anyway).
Cheers
Re: Capacitor bank/can crusher...
Sulaiman, Fri Oct 15 2010, 04:59AM
Ah,
..... ye olde ceiling perforator!
Sulaiman, Fri Oct 15 2010, 04:59AM
Ah,
..... ye olde ceiling perforator!
Re: Capacitor bank/can crusher...
Nicko, Mon Oct 25 2010, 07:53PM
Top post updated with progress...
Nicko, Mon Oct 25 2010, 07:53PM
Sulaiman wrote ...
Ah,
..... ye olde ceiling perforator!
Might be Ah,
..... ye olde ceiling perforator!
Top post updated with progress...
Re: Capacitor bank/can crusher...
Arcstarter, Wed Oct 27 2010, 12:20AM
Oh jeez! With 624 joules at 800v i could make a disk disappear into the sky, and the inertia alone caused it to break if i had a piece of steel above it... And they are normal caps, not low ESR, with 12 gauge wire coil...
I would be scared of that bank, especially at 2200j! Be careful...!
Arcstarter, Wed Oct 27 2010, 12:20AM
Oh jeez! With 624 joules at 800v i could make a disk disappear into the sky, and the inertia alone caused it to break if i had a piece of steel above it... And they are normal caps, not low ESR, with 12 gauge wire coil...
I would be scared of that bank, especially at 2200j! Be careful...!
Re: Capacitor bank/can crusher...
Nicko, Wed Oct 27 2010, 05:41AM
Cheers
Nicko, Wed Oct 27 2010, 05:41AM
Arcstarter wrote ...
Oh jeez! With 624 joules at 800v i could make a disk disappear into the sky, and the inertia alone caused it to break if i had a piece of steel above it... And they are normal caps, not low ESR, with 12 gauge wire coil...
I would be scared of that bank, especially at 2200j! Be careful...!
Its also intended as a can-crusher... and general nasty bit of kit...Oh jeez! With 624 joules at 800v i could make a disk disappear into the sky, and the inertia alone caused it to break if i had a piece of steel above it... And they are normal caps, not low ESR, with 12 gauge wire coil...
I would be scared of that bank, especially at 2200j! Be careful...!
Cheers
Re: Capacitor bank/can crusher...
Dalus, Wed Oct 27 2010, 06:12AM
Think that describes this machine the best a nice but nasty bit of kit
Dalus, Wed Oct 27 2010, 06:12AM
Think that describes this machine the best a nice but nasty bit of kit
Re: Capacitor bank/can crusher...
Killa-X, Wed Oct 27 2010, 02:56PM
Good luck on your capacitor bank! Hope it all works out for you =) I recently got 4KJ of capacitors, now total 8KJ. Guess I'll have to see how yours goes...
As for the charger, anything in mind? Maybe a simple variac + MOT?
Don't forget the safty discharge too...never know.
Killa-X, Wed Oct 27 2010, 02:56PM
Good luck on your capacitor bank! Hope it all works out for you =) I recently got 4KJ of capacitors, now total 8KJ. Guess I'll have to see how yours goes...
As for the charger, anything in mind? Maybe a simple variac + MOT?
Don't forget the safty discharge too...never know.
Re: Capacitor bank/can crusher...
Nicko, Wed Oct 27 2010, 08:03PM
As for safety discharge, the contactors I'm using have 3 n/o sets and one n/c. The HT charging contactor has its n/c contacts set to connect a 5K 50W resistor across the bank. So, if the power fails or the logic craps out, there will always be a meaty resistor across the bank.
This is also the reason I use an analogue meter which is always connected across the bank - even if the power fails, you can still see what's waiting there to bite you... (though it should slowly roll off over a couple of minutes due the resistor mentioned above).
PS. When I fired it at 300V this evening, it shattered my nice acrylic frame for the launch pad and the disc went ricocheting around my workshop
Cheers
Nicko, Wed Oct 27 2010, 08:03PM
Killa-X wrote ...
As for the charger, anything in mind? Maybe a simple variac + MOT?
Don't forget the safty discharge too...never know.
I have a 200mA step-up xfrmr in there at the moment (230VAC->360VAC) which I drive from my control box (includes a 15A variac).As for the charger, anything in mind? Maybe a simple variac + MOT?
Don't forget the safty discharge too...never know.
As for safety discharge, the contactors I'm using have 3 n/o sets and one n/c. The HT charging contactor has its n/c contacts set to connect a 5K 50W resistor across the bank. So, if the power fails or the logic craps out, there will always be a meaty resistor across the bank.
This is also the reason I use an analogue meter which is always connected across the bank - even if the power fails, you can still see what's waiting there to bite you... (though it should slowly roll off over a couple of minutes due the resistor mentioned above).
PS. When I fired it at 300V this evening, it shattered my nice acrylic frame for the launch pad and the disc went ricocheting around my workshop
Cheers
Re: Capacitor bank/can crusher...
pauleddy, Wed Oct 27 2010, 08:27PM
well i have 16 4700mfd 400v caps that built a 800v bank with, but i never got results like that even with a short wire(thin wire that burns out to shorten the pulse) i only got up to 20-30ft
PS how do you calc ESR?
pauleddy, Wed Oct 27 2010, 08:27PM
well i have 16 4700mfd 400v caps that built a 800v bank with, but i never got results like that even with a short wire(thin wire that burns out to shorten the pulse) i only got up to 20-30ft
PS how do you calc ESR?
Re: Capacitor bank/can crusher...
Nicko, Wed Oct 27 2010, 10:26PM
ESR is calculated from the PEH169 datasheet which quotes 17milliohms ESR for each of these caps, and there are 4 in parallel. They are very expensive pulse-rated & long life. The PEH200s I have are listed by Farnell at GBP 91 each (Farnell p/n 1679494) and by RS at much the same (RS p/n 311-1254). Only about USD 90 though from Digikey
I have put 169s in there at the moment as I have an awful lot of them, but they are very similar to the 200s...
Cheers
Nicko, Wed Oct 27 2010, 10:26PM
pauleddy wrote ...
well i have 16 4700mfd 400v caps that built a 800v bank with, but i never got results like that even with a short wire(thin wire that burns out to shorten the pulse) i only got up to 20-30ft
PS how do you calc ESR?
Top post updated with more photos.well i have 16 4700mfd 400v caps that built a 800v bank with, but i never got results like that even with a short wire(thin wire that burns out to shorten the pulse) i only got up to 20-30ft
PS how do you calc ESR?
ESR is calculated from the PEH169 datasheet which quotes 17milliohms ESR for each of these caps, and there are 4 in parallel. They are very expensive pulse-rated & long life. The PEH200s I have are listed by Farnell at GBP 91 each (Farnell p/n 1679494) and by RS at much the same (RS p/n 311-1254). Only about USD 90 though from Digikey
I have put 169s in there at the moment as I have an awful lot of them, but they are very similar to the 200s...Cheers
Re: Capacitor bank/can crusher...
Killa-X, Wed Oct 27 2010, 10:41PM
Niiice. You should sometime hook some series too for higher voltage, so you can do some elecrothermal gun shooting possibly =) I got one coming eventually, Just waiting to buy my lathe in a few months.
Hope your stuff goes well, I know people with RIFCA capacitors, those things rock =D
Killa-X, Wed Oct 27 2010, 10:41PM
Niiice. You should sometime hook some series too for higher voltage, so you can do some elecrothermal gun shooting possibly =) I got one coming eventually, Just waiting to buy my lathe in a few months.
Hope your stuff goes well, I know people with RIFCA capacitors, those things rock =D
Re: Capacitor bank/can crusher...
Nicko, Wed Nov 03 2010, 03:36PM
Squashed a few coke cans too...
Cheers
Nicko, Wed Nov 03 2010, 03:36PM
Killa-X wrote ...
Niiice. You should sometime hook some series too for higher voltage, so you can do some elecrothermal gun shooting possibly =) I got one coming eventually, Just waiting to buy my lathe in a few months.
Hope your stuff goes well, I know people with RIFCA capacitors, those things rock =D
Top post updated with schematic as used at Cambridge Teslathon. Happily launched disc platters round the room with considerable force as they pinged off the ceiling etc.! Never went over about 1200J as the launch pad ripped itself apart and the discs were distorting heavily - need to re-do that and embed it in epoxy.Niiice. You should sometime hook some series too for higher voltage, so you can do some elecrothermal gun shooting possibly =) I got one coming eventually, Just waiting to buy my lathe in a few months.
Hope your stuff goes well, I know people with RIFCA capacitors, those things rock =D
Squashed a few coke cans too...
Cheers
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