Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Mddeming-at-aol-dot-com>
In a message dated 3/6/02 10:16:40 AM Eastern Standard Time, tesla-at-pupman-dot-com
writes:
>
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <Mildewhaus-at-aol-dot-com>
>
> Hi guys! I wrote the list about the 50 or so 14.5 uf ,700vpk GE caps that i
> have. Question, why if i put enough of them in series can i not load them up
> with a NST?I can load them up with an HV battery powered(100 vdc) "coil" from
>
> a copier.They will also load from my house 120ac.I have used one in the car
> coil,dimmer switch circuit,and it almost doubles the spark output.What's the
> downside to doing this?These caps are large spam can types.Any help? Thanks
> guys!
> john in nyc
>
>
Hi John,
Using these in a TC tank circuit has two problems, not counting the
hernia you may get trying to move so massive a cap farm. ;-))
1. They are not really designed for high frequency applications; about kHz is
the top they were designed to handle. Internal resistance means
charge/discharge time is much slower than caps made for HF applications. Losses
(esp. heating) tend to go up exponentially with frequency.
2. A string of 50 will give you 290 nFd -at- 35KV. This would match well with a
tank supply of a coil handling 50-150 KVA, but the resonant frequency with any
decent size primary would be down in the dirt (~ 20KHz) A secondary resonant at
these freqs. would have to be MASSIVE. Seems like a bit of overkill, unless you
are really thinking BIG!
I also have 50 15ufs -at-660V, but I use them for PFCs and other low
frequency apps. as per earlier post. I'm not saying it can't be done, but the
scale seems wrong for the average coiler.
Regards to B'way,
Matt D.
G3-1085