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Re: Limiting Safety Gap Current



Tesla List wrote:
> 
> Original Poster: Mark S Graalman <teslac-at-juno-dot-com>
> 
>   I made comments on this a number of months ago. A
> safety gap across the primary gap is a BIG MISTAKE
> it WILL cause destruction of the cap sooner or later.
>  A gap acrossed the cap sets up a very high frequency
> high current circuit that is coupled to NOTHING and a
> huge standing wave is set up. A inductive loading of the
> circuit will simply lower the frequency of the circuit and
> slightly lower the peak current, the energy will not be
> dissipated in the reactance of the inductors but returned to
> the cap. Some may disagree, but I've killed a lot of caps this
> way, it is NOT the way to do it.
> 
> Mark  Graalman
> 

Mark,

Come on, I have been using safety gaps on my caps for almost ten years
and have NEVER lost a cap to a safety gap. I have, however, heard of
dozens of coilers losing caps to overvoltages and transient spikes by
NOT using a safety gap. Just one large overvoltage can send a cap to the
great beyond!

A safety gap is only to protect from the occasional overvoltage or
transient and will not fire on a properly tuned system anyway. If the
safety gap on a system is firing frequently SOMETHING IS WRONG and the
situation must be corrected!

One final point. All high energy discharge capacitors have finite
lifetimes, usually stated by the manufacturers as number of shots, based
on rated voltage, rep rate, etc. and WILL fail sooner or later. We hope
later rather than sooner!

Ed Wingate RATCB