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Re: Power Load Balance Concern



Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>" <youngs-at-konnections-dot-net>

Matt,
Consider using your 4 NSTs with the primaries wired in series-parallel (2
sets of 2 in series, parallel the series sets) and run from 240 V.  You can
run one leg of the 240 directly to your NSTs and run the other leg through
your variac, using the neutral as the common connection for the NSTs and the
variac.  Thus your control range will be 120 - 240 volts which ought to be
OK.  This keeps the current below 20 amps.

--Steve
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, September 23, 2001 12:52 PM
Subject: Power Load Balance Concern


> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Mddeming-at-aol-dot-com>
>
> Hi All!
>         I am in the process of upgrading my power supply to 4 15/60 NSTs
and
> already have a 120v input -at-30Amp,  model W30M Variac. Based on nameplate
> ratings, the NST bank  should draw about 33 Amps total (4X8.25). The
problem:
> since there is only one open slot left in my breaker box, I would like to
use a
> 40Amp breaker, but I have not seen single breakers for this kind of
current.
> Most are dual breakers -at- 240 V using both sides of the line to keep the
load
> balanced and prevent in-house brown-outs.  If I try to get a 4KVA
> step-down/isolation transformer so as to utilize both sides of the line, I
am
> looking at ~$350 plus S&H on 120 lbs.
> Questions:
> 1. Is running the Variac at +10% a real concern?
> 2. Is placing this size load on one side of the panel going to create
in-house
> imbalance problems?
> 3. Anyone got a cheap step-down 4KVA transformer?
>
> Would appreciate response from any/all with experience in this area.
>
> Matt D.
> G3-1185
>
>
>
>