Re: [TCML] 5.25" SRSG tesla coil suggestions on improving performance

[Gary Lau <glau1024@xxxxxxxxx>]

Hi JJ,

I have no advice for bettering the performance, but your RSG construction
concerns me.  Given that your stationary electrodes are glowing red-hot, it
would seem likely that your rotating electrodes are also mighty hot despite
their better cooling, and that their mount in the acrylic disc is likely to
be perilously vulnerable to softening and fracture.  Unfortunately I don't
see an easy fix here.

Regards, Gary Lau
MA, USA

On Mon, Aug 5, 2013 at 9:59 PM, JJ Dasher <redrum0381@xxxxxxxxx> wrote:

> Hi all,
> I'm new here.  Although I've built a few coils in my past, I still
> consider myself a newb coiler.  I've never been the type to do things
> mathematically perfect, and tend to wing it as I go along, which may be my
> downfall here.  For the past couple of years on and off, I've been working
> on a 5.25" SRSG coil to use in a Halloween display.  This is my largest
> coil so far.  You can see it in action here:
>
> http://www.youtube.com/watch?v=2P3T5zuT9DI
>
>
> and pictures of the guts here:
>
> http://imgur.com/a/0jgxR
>
>
>
> I'd like to get some constructive criticism and advice on getting this
> running better.  This trips my 20amp breaker after about 10-15 seconds of
> running, so I figure about 2.2-2.6kw?  I'm currently getting 36" streamers,
> which I feel are somewhat weak.  They are purple, and not very bright.
> Specs:
>
> Large old powerstat variac salvaged from power equipment.  Not sure on
> exact specs, but I assume it should handle 30+amps with ease.  Wired for
> approx 150v boost.
>
> Dual MOT's (pulled from 1200w commercial MWs), currently unballasted.
>  130uf of PFC caps behind them.
> 180nf MMC cap built with 10 strings of 8x 942c20p15k-f's.  1m bleed
> resistors installed.
> SRSG is a 5" acrylic disc attached to a 1800rpm sync motor.  4 flying
> electrodes for 120bps.  Electrodes are 1/8" thoriated tungsten.  Phase is
> adjusted by twisting the motor in its mounts.
> Primary is 3/8 copper tubing, slightly conical.  Currently tuned at about
> 2.25" turns
> Secondary is 5.25" x 24" 22awg magnet wire with a couple of coats of poly.
> Topload is a spun aluminum 4.5"x18" toroid.
> All high current busses are 4awg stranded copper with large soldered lugs.
>
> The next improvement I plan is to upgrade to 1/4" tungsten electrodes.
>  The stationary electrodes currently glow red hot after about 5 seconds of
> running, so I added a fan.
> I'd love to get some bright long white snakes like I've seen from similar
> size coils.  Please advise!
>
> Thanks!
> JJ
>
> P.S.  There is normally a safety gap installed, It just wasn't in place
> when I took those pictures.
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>
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