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Re: Very Confused On Grounding

Original poster: "Daniel Koll" <dk_spl_audio@xxxxxxxxxxx>

Gerry, thanks for the reply on how the Terry Filter and RF is at the same voltage level, thus RF won't harm the NST. That makes sense. I guess the only thing left to debate is my comment on how RF will be "floating" on my EMI filter case and, if grounded to mains, will go into my houses ground.
Sorry for being so persistant but I really am enjoying learning how to make this a non destructive operation.

From: "Tesla list" <tesla@xxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: Very Confused On Grounding
Date: Tue, 17 May 2005 11:44:49 -0600

Original poster: "Gerald  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>


Original poster: "Daniel Koll" <dk_spl_audio@xxxxxxxxxxx>

-Connect the NST case to RF ground with Terry Filter connected to NST case (can't RF get into the mains via the NST's primary connections then?) 

Thats what the EMI filter is for (to keep the RF off of mains HOT and NEUTRAL.

-Use mains ground for NST case (the problem with this option is the RF ground and mains ground would be connected together via the Terry Filter.
If I use mains ground then I would think that the Terry Filter should not be connected to the NST case (is this even an option) to avoid coupling the grounds.

The Terry filter and center terminal of the safety gap should always be connected short as possible and directly to NST case. It is voltages on the bushings with respect to the NST case that is damaging to the NST. If the NST case is connected to mains safety ground, the terry filter and safety gap should also be connected to mains safety ground (and not RF ground). If the NST case is connected to RF ground, the Terry filter and safety gap should also be connected to RF ground (and not to mains ground).

Gerry R



From: "Tesla list" <tesla@xxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: Very Confused On Grounding
Date: Mon, 16 May 2005 10:47:53 -0600

Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>




Original poster: "Daniel Koll" <dk_spl_audio@xxxxxxxxxxx>

It's a modified sine wave, oh well. I will just do what I said and not use mains ground at all and have the NST case floating. I think that will be the safest way for my houses equipment. Thanks

Probably a bad idea to have the case floating or anything else for that matter.

1. Floating items have tendency to build up a charge via leakage paths and corona pickup.
If the voltage builds too high it can break down the insulations permanently.

2. If for some reason high voltage does get to the case it may jump to the mains input and permanently damage the insulation as in 1.

3. RF coupled from the secondary will probably produce a much higher voltage on the case than if the case is grounded.
The higher case RF voltage will couple more voltage to the mains input.

I agree with others that have stated "connect it to RF ground" for minimum RF back to the mains.


Robert (R. A.) Jones