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Registered Member #2148
Joined: Tue Jun 02 2009, 02:22AM
Location:
Posts: 62
HI GUYS/PROFESSIONALS GOOD DAY THE LAST THING THAT I WILL BE DESIGNING IS MY MMC BANK AND MAIN SPARK GAP, MY CAPS WILL BE ARRIVED IN THIS MONTH SO IM STILL WAITING, I TESTED MY OLD STATIC GAP DESIGN BUT IT FAILED, THE BASE WHERE THE ELECTRODES MOUNTED IS MELTED. NOW IM GOING FOR A SUCKER GAP.
THE REST... PLS INSPECT MY TESLA COIL DESIGN AND POINT OUT/OBSERVE/LOOK FOR ANY MISTAKES/STUPIDITY THAT IVE DONE AND PLS GIVE SOME SUGGESTIONS/RECOMMENDATION SO I CAN CORRECT IT
THERES ARE SOME QUESTIONS ON EVERY PICTURE...
THANK YOU! i deleted photos because i dont have time to resize, will repost it sooner
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
Looks pretty good. My question is: What's with the bottom end of your coil? You need to bring that down for grounding.
Primary looks good. Close spacing will give you a strong tight field and more inductance, so you will need fewer turns to get the job done. On the flip side of that, fewer turns needed on a large primary leads to autotransformation like a flyback and you can have very high voltages at the end of your primary, so bare that in consideration. I've had only a couple of issues with mine, but other then that you will see normal operation.
HV wire is fine for connecting the transformers to the cap, but other then that, far too lossy to connect the tank circuit. The wire will get hot. If you plan on using it, make it very short and possibly double it up.
Remember that the wire will be a few uH, and your tank will be maybe 30uH total. If your leads are 3uH, that means 10% of your power is going through those leads, and we're talking a couple hundred amps at over 20,000V, so you want to make sure those leads are very short.
You're probably overcoupled with the amount of power you plan to use there, so crank up a variac real slow and see what you get. You should be quite satisfied with the 4 foot + streamers you're going to get.
I would recommend taking out your metal adjustment screws for the coupling because its relatively at ground potential compared to your primary. It's going to arc over.
Check out the CDE capacitor banks that everyone is building. You're going to need a heafty cap bank for your final build.
Lastly, because of what I would expect to be your streamer length, do NOT run the wire inside the coil form. This is a typical big no no. With a "hot" coil, even with one transformer, you can have your streamer run down the inside of your form and eat itself. One of mine was doing that real bad and diminished its performance. So leave the secondary outside the form, just glue it down real well.
If this is your first coil, I'd say you've done a hell of a job.
Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
Yes, i must agree. If this is your first, second, 5th coil, it looks badass. Good job.
I would definitely suggest avoiding any metal inside of the secondary former. If you want to really max this coil out, (as you would be able to do much more than max it out with two NST's, depending on the rating) it would be a good idea to avoid it, though if you used a breakout point, or you got streamers before an internal arcover, it would likely present enough of a load to keep the voltage from rising high enough to break down inside the pipe. Then again, keep in mind that surface tracking might occur...
Just as Hazmatt said, 17 gauge is fine for the NST hookup to the terry filter, and from the filter to the cap, and high current paths need to be much thicker. If you have some soldering skills with thick stuff and some leftover copper pipe, you can use that, and you can even flatten the pipe if you want.
I would suggest using only one of those NSTs if they are something like 12kv 60ma (looks about that size) and tuning until you max the secondary out. If the NSTs are like 12kv and 30ma though, parallel sounds good.
That sucker gap would do very good if you use a strong vacuum motor. If you still want more spark length and greater overall efficiency, for me a srsg increased performance a *lot*. With 3 MOTs in series limited to 600 watts, with a srsg i got about 4 foot sparks from my 24 inch secondary. Before the srsg i only got about a foot of sparks when tuned. Was a really awful spark gap at first though.
On the flip side of that, fewer turns needed on a large primary leads to autotransformation like a flyback and you can have very high voltages at the end of your primary, so bare that in consideration. I've had only a couple of issues with mine, but other then that you will see normal operation
That is very interesting. I have never really put much thought into that. However, fewer turns does however mean smaller resistance losses.
It is not my place to get onto you, but please don't use caps lock. Thanks :)
Registered Member #1643
Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039
I noticed those NSTs and thought it was a 12kv 60ma. I like the looks of your coil, similar to the frame design I had in mind. I also wonder about then LEDs. I would guess if they sent grounded it it's fine. I my self like the ideas of the LEDs. Blue and red are my favorite colors, knowing me and enjoying to overkill on looks, I would make the 2 colors fade :). Love the looks, hopes it all goes good! Good luck :D
Registered Member #2148
Joined: Tue Jun 02 2009, 02:22AM
Location:
Posts: 62
Hazmatt_(The Underdog) wrote ...
Looks pretty good. My question is: What's with the bottom end of your coil? You need to bring that down for grounding.
Primary looks good. Close spacing will give you a strong tight field and more inductance, so you will need fewer turns to get the job done. On the flip side of that, fewer turns needed on a large primary leads to autotransformation like a flyback and you can have very high voltages at the end of your primary, so bare that in consideration. I've had only a couple of issues with mine, but other then that you will see normal operation.
HV wire is fine for connecting the transformers to the cap, but other then that, far too lossy to connect the tank circuit. The wire will get hot. If you plan on using it, make it very short and possibly double it up.
Remember that the wire will be a few uH, and your tank will be maybe 30uH total. If your leads are 3uH, that means 10% of your power is going through those leads, and we're talking a couple hundred amps at over 20,000V, so you want to make sure those leads are very short.
You're probably overcoupled with the amount of power you plan to use there, so crank up a variac real slow and see what you get. You should be quite satisfied with the 4 foot + streamers you're going to get.
I would recommend taking out your metal adjustment screws for the coupling because its relatively at ground potential compared to your primary. It's going to arc over.
Check out the CDE capacitor banks that everyone is building. You're going to need a heafty cap bank for your final build.
Lastly, because of what I would expect to be your streamer length, do NOT run the wire inside the coil form. This is a typical big no no. With a "hot" coil, even with one transformer, you can have your streamer run down the inside of your form and eat itself. One of mine was doing that real bad and diminished its performance. So leave the secondary outside the form, just glue it down real well.
If this is your first coil, I'd say you've done a hell of a job.
Hi ill note all of that! thank you. firstly this is my first coil to build.
grounding is connected to the bolt at the bottom and wired up through the ground, thats what im going to do.
i will replace those metal bolts with plastic or nylon bolt. hope i find soon because honestly that was my first plan but it really hard to find locally
i dont have any metal inside the coil, but there are some at the top but not in the COIL inside?
im working on my spark gap now. i have a vacuum for cooling the electrodes.
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
No part of the secondary should be inside your former because you will have a racing arc down the inside of the tube. You can't see it when it happens, which makes things difficult. You may hear a cracking sound inside the tube, but that's about it.
Metal should be avoided because it can act as a breakout point, or HV stress point. A large potential can build up and cause a burn on the plastic, which causes carbon tracking and eventually a large spreading conductive burn. That's worst case, but should still be avoided.
For the top try a T type plug or an end cap. Many people use this so they don't need fasteners.
Registered Member #2148
Joined: Tue Jun 02 2009, 02:22AM
Location:
Posts: 62
Arcstarter wrote ...
Yes, i must agree. If this is your first, second, 5th coil, it looks badass. Good job.
I would definitely suggest avoiding any metal inside of the secondary former. If you want to really max this coil out, (as you would be able to do much more than max it out with two NST's, depending on the rating) it would be a good idea to avoid it, though if you used a breakout point, or you got streamers before an internal arcover, it would likely present enough of a load to keep the voltage from rising high enough to break down inside the pipe. Then again, keep in mind that surface tracking might occur...
Just as Hazmatt said, 17 gauge is fine for the NST hookup to the terry filter, and from the filter to the cap, and high current paths need to be much thicker. If you have some soldering skills with thick stuff and some leftover copper pipe, you can use that, and you can even flatten the pipe if you want.
I would suggest using only one of those NSTs if they are something like 12kv 60ma (looks about that size) and tuning until you max the secondary out. If the NSTs are like 12kv and 30ma though, parallel sounds good.
That sucker gap would do very good if you use a strong vacuum motor. If you still want more spark length and greater overall efficiency, for me a srsg increased performance a *lot*. With 3 MOTs in series limited to 600 watts, with a srsg i got about 4 foot sparks from my 24 inch secondary. Before the srsg i only got about a foot of sparks when tuned. Was a really awful spark gap at first though.
On the flip side of that, fewer turns needed on a large primary leads to autotransformation like a flyback and you can have very high voltages at the end of your primary, so bare that in consideration. I've had only a couple of issues with mine, but other then that you will see normal operation
That is very interesting. I have never really put much thought into that. However, fewer turns does however mean smaller resistance losses.
It is not my place to get onto you, but please don't use caps lock. Thanks :)
Hi, sorry for typing in all caps, would not do that anymore. it is my first coil to build and im so excited when im done but i have so many things to do first, like school, job training etc.. so i cant give it a time for work.
my NST is rated @ 15kv 30ma each, so paralleling the two will give me 15kv@60ma i phased them early and it gave me a lil longer and more fatty arc.
You said if my NST was like 12kv 60ma each, then why would I use only one instead of 12kv @ 120ma? is it because my spark gap cant handle it? btw i have a salient pole motor, i dont know how to modified it to sync. or is it sync already? i dont understand. i dont have proper tools to do it. i have a tachometer and i measured its speed which is 3475 rpm no load, sometimes 3475-3490rpm is it sync?
can i use a really thick wire but not meant for high voltage for my MMC to primary winding?
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I don't care about caps lock (I have earplugs) but the forum rules prohibit images wider than 400 pixels. You agreed to the rules when you signed up, so please go back and resize those images, or we'll just delete them.
Registered Member #480
Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644
eniyuki -
A few comments -
1. If you already have a nice spun-aluminum toroid, why are you considering construction of a toroid from convoluted duct material? The spun toroid will probably give better perfoamance than a home-made toroid because of its near-perfect surface (free from from any irregulartiies). Regarding the "home-made" toroid, what is the toroid material actually made from? it looks like it may be made from metallized plastic material wound over a spring wire form. This material won't work, you need duct material that's constructed from heavy aluminum foil. To verify what your material is, simply apply a flame from a match or lighter. If it melts instantly, it's plastic. If if is completely unaffected by the flame, it's aluminum.
2. Install a close-fitting plastic baffle (~5-10mm thick) inside your secondary coilform, a few inches down from the top turn of wire, and carefully seal it to the inner wall of the form using RTV silicone or acrylic caulking material. Make sure that the seal has no pinholes or voids. One baffle should prevent any internal arcing iin your secondary, even if you have run the secondary wire inside the form at the top or the bottom.
3. What type of metal are your spark gap electrodes (the threaded flare-tube fittings) made from? Aluminum or stainless steel? How will you connect the primary wiring to these fittings? The sharp "front edge" of these electrodes may tend to erode fairly quickly; you may want to file or sand them until they have a 2-3mm "flat" on the front edges to give more functional area where the arcing will take place.
Overall, your construction looks very nice, especially if this is your "first coil".
Registered Member #2148
Joined: Tue Jun 02 2009, 02:22AM
Location:
Posts: 62
hi herrzapp I didnt understand n0.2, can you provide a picture?
The reason why im constructing an0ther toroid is because my current toroid is small. The air duct is made from thick aluminum which is really hard to tear,i cant tear it. My plan is to smooth its surface using a wall filler just like in teslalegacy website then wrap it in aluminum tape,the two plates are also made from aluminum.
Those two electrodes i think it is made from steel coated with brass, i cant find copper tubes locally with a diameter larger than 3/8 in. really! Its a pain in the a.. Can i use brass 10mm dia. 2mm thick then build multi gap? I think it is better?
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My SGTC (design and recommendation)
