RE: Phasing parallel coil and core NSTs

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

Original poster: "Vanderputten, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <gvp-at-pvaintl-dot-com>



 -----Original Message-----
From: 	Tesla list [mailto:tesla-at-pupman-dot-com] 
Sent:	Tuesday, April 16, 2002 3:20 PM
To:	tesla-at-pupman-dot-com
Subject:	Re: Phasing parallel coil and core NSTs

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Esondrmn-at-aol-dot-com>
In a message dated 4/15/02 10:18:36 PM Pacific Daylight Time,
tesla-at-pupman-dot-com writes:

>
> I am making a small 250 w coil powered by 2 identical 5kv/25ma open core
and
> coil neon transformers.
> 1. I noticed that neither will arc to the core and therefore appear not
> center grounded. Are there issues with phasing the two in parallel? 
>
> 2. Should I ground the cores to the mains ground or the RF ground? With my
> other coils I ground the case to the RF ground.
>
> 3. Even though it is small, I am installing a Cap and resistor style NST
> protection circuit. Is this necessary ( I have the spare parts)? 
>
> Gary



Gary,
I would measure the secondary to core resistance.  If it is open circuit,
then the core is floating and there is no center tap connected to the core.
If it measures one half of the total secondary resistance, then you know
there is a center tap that is connected to the core.  In this case, I would
ground it.

Check - it is an open circuit.


To check parallel transformer phasing, set the two transformers up in the
position that you want to use them and connected the primaries in parallel.
Now connect one side of each secondary output together.  With power applied,
you should get a very small spark or no spark when the other two secondary
leads (one from each transformer) are brought together.  You can now connect
these secondary leads together.  If you get a large spark, reverse the
primary connections to one transformer and try the test again.
Ed Sonderman

Thanks to all for their helpful comments.

Gary