Re: Doubling NST voltage? (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: List moderator <mod1@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Mon, 30 Oct 2006 15:53:23 -0500
From: Mike <mike.marcum@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Doubling NST voltage? (fwd)

Another option would be to take the 6/20 open-core (no tar to deal with) 
nsts and series 3 (best if the center one is a midpoint grounded version) 
and submerge at least the outer 2 in oil (all 3 if no midpoint ground). 
These types have considerable space between the core and windings so the oil 
helps quite a bit.

Mike
----- Original Message ----- 
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, October 30, 2006 2:04 PM
Subject: Re: Doubling NST voltage? (fwd)


> Original poster: List moderator <mod1@xxxxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Mon, 30 Oct 2006 10:00:45 -0800
> From: Jim Lux <jimlux@xxxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Doubling NST voltage? (fwd)
>
> At 06:45 AM 10/30/2006, you wrote:
>>Original poster: List moderator <mod1@xxxxxxxxxx>
>>
>>
>>
>>---------- Forwarded message ----------
>>Date: Sun, 29 Oct 2006 11:37:22 -0800 (PST)
>>From: C. Sibley <a37chevy@xxxxxxxxx>
>>To: Tesla list <tesla@xxxxxxxxxx>
>>Subject: Re: Doubling NST voltage? (fwd)
>>
>>I still don't get it, why would you need an isolation transformer for the
>>second transformer?  It seems to me there would be no problem as long as
>>the CT of the secondaries were left isolated (i.e. floating).
>>
>>Is the concern there would be a breakdown between the seconday to primary
>>within a transformer?
>
> Precisely.  The reason the centertap is grounded in a NST is that it
> makes it possible to insulate for only half the total output voltage.
> That is, a 15 kV RMS (21kV pk) transformer would only need 11kV 
> insulation.
>
> NSTs are a hugely cost sensitive device, and they don't spend a penny
> more on insulation than they absolutely need to.
>
> They do breakdown if hooked up in series.  Typically, since the
> secondary is connected to the core (at the midpoint), the breakdown
> is core to primary (at least in my transformers I've tried this with)
>
>
>
>
>