RE: Wiring two 15KV 240V/50Hz Transformers in Series for use with 110V (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 15 Jun 2007 09:42:34 -0400
From: "Lau, Gary" <Gary.Lau@xxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: Wiring two 15KV 240V/50Hz Transformers in Series for use with 110V
    (fwd)

Hi Chris:

Sorry, but you can't do what you propose.  15kV NST's are made with the
secondary midpoint connected to the case.  If you connect the
secondaries in series, the two cases will have 15kV between them.  The
primary-to-case insulation is not designed to sustain that and will
fail.

Most US households have 240V available in the breaker box to power
electric stoves, dryers, and other large appliances.  You'll have to use
the NST's at their rated input voltage.  If you're in an apartment that
doesn't have 240V available, your only alternative is to get a 120/240
step-up xfmr.

Regards, Gary Lau
MA, USA


> Date: Fri, 15 Jun 2007 14:10:05 +0800
> From: westland <westland@xxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Wiring two 15KV 240V/50Hz Transformers in Series for use with
110V
> 
> I have an interesting variant on one of the questions that just came
up
> about series wiring of transformers.  I'll be moving to Chicago in two
> months, and from 220V to 110V mains.  I currently have two 15KV
> 240V/50Hz/0.03A Transformers wired in parallel (for .060A) that power
my
> TC.  I'm wondering if there is any problem switching leads around for
> 110V/60Hz ... running the secondary in series, and the primaries in
> parallel.  I figure since its a 50Hz transformer, it's already about
20%
> overengineered, and the secondaries takes 15KV at .03A, so I should
end
> up with output of 15KV at .03A (rather than the 0.03A I get in Hong
Kong).
> 
> I'm looking for a sanity check on my logic, just to make sure that I
> don't bring them to the States only to burn them up.  Clearly, I can
> keep the current arrangement, and just precede them with a 110 to 220V
> stepup transformer.
> 
> Chris Westland
> 
> --
> 
> ___________________________________________________
> 
> J. Christopher Westland, PhD CPA
> Professor, ISMT, University of Science & Technology, HK Clearwater
Bay,Kowloon,
> Hong Kong
> Tel: 852 2358 7643
> Fax: 852 2358 2421
> Mob: 852 9528 1745
> URL: ihome.ust.hk/~westland
> Mobile e-mail: chris.westland@xxxxxxxxxxxx
> 
>