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Steve Ward

Wed May 30 2007, 12:39AM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

Getting MMC caps fast is tricky. You can check ebay, sometimes there are MMC caps for sale at a slight mark up in cost.

For wiring, id suggest no less than 16awg wire. The little clip lead sets you get from radioshack are often too wimpy for this sort of use. I often make my own heavy duty clip leads from heavier wire and stick my own aligator clips on the end..

Yongsoo

Wed May 30 2007, 01:00AM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

would i be making resonant capacitor, static gap ltr capacitor, or a srsg ltr capactor?

and would these work?

it says 2000vdc and i think my transformer is ac

Coronafix

Wed May 30 2007, 03:19AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Go for static gap LTR cap bank, so with your tranny
you should be aiming at 11 or 12 nF.

GreySoul

Wed May 30 2007, 04:51AM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

those are probably the best caps around for building MMCs.

For your 12/30 NST you'll need 15 of them. that gives you .0099uF in a static gap larger than resonant (LTR) MMC. (edit: I get my acronyms wrong a lot, sorry)

Also, a decently cheap source of wire are the cheap 16ga orange extension cords from home depot. you get like 75' of wire (25' x black, white, and green) and a male and female connector. You can use the male end to get power to your NST if it doesn't come with a cord. The female end is great for adding to a variac.

now get busy.

-Doug

Coronafix

Wed May 30 2007, 07:03AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

LTR = Larger than resonant
Resonant x 1.414

Yongsoo

Thu May 31 2007, 12:15AM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

Okay, I have my magnet wire and my pipe and I have no idea how to get started. Where/how do I start the secondary coil and how do I keep the wire from unraveling?

GreySoul

Thu May 31 2007, 12:42AM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

I used tape as I wound my coil...by hand...very slowly. it took me the better part of a day to get it done right.... I messed up a lot the first attempt.

don't use too much tape, or you'll deform the coil when you remove it. when all is said and done you can use lacquer, Glyptol, or polyurethane to seal the whole coil. I opted for about 2 cans of Krylon electronic grade clear coat. then a layer of old amber lacquer for color.

As for winding.... tape the wire to the coil about 3-4" from one end of the pipe and start coiling. It's best not to drill a hole to pass the wire through or you will experience internal arcing/racing. A simple winding jig can be made with some skateboard or roller blade wheels and PVC/metal/wood so that you can roll the pipe on a level plane and control tension on the wire.

You'll want about 1000 turns, so figure the number of turns per inch and extrapolate from there. There are some nice charts out there to get the exact number of turns per inch, hit up google for Tesla coil design sites.

always overestimate the length of pipe you'll need for your first coil.... I figured 2' would be plenty and by 22" I was out of room @ 700 turns or so. It works ok, but it's not ideal.

-Doug

Yongsoo

Thu May 31 2007, 01:54AM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

Do I tape the inside or the outside?

And for my pipe, I couldn't find any 3 inch pvc pipes. The best I found was this 3"x2' abs pipe which I was told it was made out of polyurethane but I found out it's a black pvc pipe which the hvwiki tells me not to use. Do I need a new pipe? and where would I be able to obtain one.

CT2

Thu May 31 2007, 02:30AM

Registered Member #180 Joined: Thu Feb 16 2006, 02:12AM
Location: Ontario, Canada
Posts: 187

You tape over your wire to hold it in place as you wrap it, your wire is on the outside of the pipe. As to the ABS question, some say it's bad others say it doesn't matter, personally I have used both and I didn't have a problem with the ABS. My coil was small though (2"x8") so there may be issues with a larger coil.

GreySoul

Thu May 31 2007, 03:01AM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

if you're stuck with black ABS plastic then I'd say at least coat it with a layer or two of clearcoat or lacquer.

As for the tape, just use little strips, like 1" long of scotch tape, to hold your work as you go. Alternatively you can use super glue, but it's gonna be impossible to fix mistakes.

....

-Doug

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