Re: Necessity of NST Protection Filters and Safety Gaps

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

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 


 > Original poster: "Luke" <Bluu-at-cox-dot-net>
 >
 > May I ask why inductors are not used instead of the resisistors since
 > the react with frequency?

Resistors are cheaper, by and large, and inductors might form a resonant
circuit with parasitic C in the transformer or other components and actually
aggravate the problem.  This isn't a nice RLC low pass filter design
exercise, since the source and load impedances are not "well behaved".  They
are reactive and dynamically varying.

 >
 > What is a MOV?
Metal Oxide Varistor, as used in "surge suppressors"

 >
 > And what is the method to properly set the safety gap?

Set the gap so that it just doesn't fire with just the NST connected to it.
If a transient propagates back to the NST that is higher than the NST output
voltage, the gap will fire, shunting the transient.

 > Are you talking about the safety gap at the Main spark gap or the safety
 > gap in the NST protection circuit?
 >