Re: Toroid selection

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 8/14/01 9:20:01 AM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

> ~MOT COIL (two xfmr/doubler)~
>  secondary: 8.5 X 26 winding, 26 awg, 1625 turns;
>  freq. 109 kHz unloaded, 49 kHz with 52 pf topload;
>  primary cap: geek mmc, 3 strings X 11 caps, 0.41 uf;
>  primary: 1/4" copper, 1/4" spacing, tapped at 16 turns for 251 uh;
>  gap: asrg- rt. angle grinder, spdt configuration, 833 bps max

Gregory,

That's a pretty large cap, I realize the voltage will still be a little 
low, so a llarge cap may be needed.  At 240 bps, I guess it will
draw about 7kW or so.  This can theoretically give about 10
or 12 foot sparks, so I guess a large toroid is well suited.  
I'm not sure offhand how large a 52pF toroid will be.  but this
seems like it may all work out.  I don't really have a lot of
experience with MOT coils, I only built one, which used 4 MOT's
in series and gave 64" sparks.
>  
>  ~15/50 COIL~
>  secondary: same
>  primary cap: MMC set to 0.27 uf
>  primary: same, tapped at 17 turns for 283 uh
>  topload: 35 pf for 57 kHz
>  gap: 120 bps srsg

I guess you mean 0.027uF,  sounds good overall.

John Freau