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Re: A new cap failure mode?
In a message dated 2/5/99 5:26:36 AM Pacific Standard Time, tesla-at-pupman-dot-com
writes:
> In an off list discussion, a topic came up that I have not seen before but
> I always assumed may be a factor in capacitor failure.
>
> When one places a nice safety gap across a capacitor, and it is firing for
> any reason, what is the current in the discharge pulse? Since Tesla caps
> are designed to be very low inductance and low resistance, there is very
> little limiting the current when the safety gap fires. If a cap is charged
> to say 20kV and the resistance of the mess is say 0.5 ohm - we get 40000
> amps!! That is enough to do some real internal damage to any capacitor.
> The suggestion comes up that perhaps a safety gap placed directly across a
> primary cap needs a little resistance in the circuit to keep this current
> to a "safe" level.
>
> Comments or suggestions are welcome...
>
> Terry
>
Terry,
Good point. When I was having primary problems a while back, and the cap
safety gap was firing, it sounded like a shotgun - scared hell out of me the
first time it went off. You know there is a lot of energy being dissipated
there.
Ed Sonderman