Re: NST protection and grounding

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

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Kurt,

At 09:48 AM 6/2/2003 +0200, you wrote:
>Hi,
>
>Elementary Q's, but I need help from you experts:
>
>1.) How important is the grounded center tap of the safety gap, when using 
>a Terry type filter? Function of the center tap? (My SRSG has only a 
>single safety gap).

Pretty important.  If one side of your system is at ground already, then 
maybe you only need "one side" of the filter.


>2.) What are the possible (-and probable-) consequences of a missed 
>grounding at the center tap of a HV center tapped NST?

RF will travel wherever it want's.  That could do all kind of "interesting" 
things.  At low powers (<1000 watts) that will probably not be to bad.  At 
high powers, it could destroy and burn up things...  Hard to say without 
knowing exactly how it is all wired in relation to ground.


>3.) The old Q:
>     Where should the NST be grounded: RF- or line-ground?
>     Here my guess:
>In order to protect the NST, it is better to connect to the line-ground, 
>because, by that way, the voltage difference between the line neutral 
>(connected to the primary)and HV-center tap is minimized. But, on the 
>other hand, in order to protect the line (-and what's connected to it), 
>from incoupling of ground strike noise, it is better to use the RF ground.

I use RF ground.  I am not concerned about the 60Hz "safety" ground 
here.  I am trying to stop the RF.  A good RF ground will also be a good 
60Hz ground.  A small voltage difference between the RF and line grounds 
does not hurt anything.

A rule is: If the ground will see RFcurrents, it needs to be an RF 
ground.  I use AC grounds for variacs, control panels, switches and other 
stuff "I" touch.  But there should be no RF there.  My control stuff does 
have RF ground studs in case I get RF leakage.  Then I can run another RF 
ground rod.

Cheers,

         Terry


>Or: I'm missing something?
>Thanks for your help!
>
>Kurt
>
>