Re: DC Supply

To: tesla-at-pupman-dot-com
Subject: Re: DC Supply
From: Greg Leyh <lod-at-pacbell-dot-net> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Fri, 25 Sep 1998 22:58:34 -0600
Approved: terryf-at-verinet-dot-com

> Original Poster: Jim Lux <jimlux-at-jpl.nasa.gov>


> But what if the primaries were fed in Delta?  120/208Y is quite common
> in light industrial/office areas, because you get the 120V to run
> everything. However, in heavier industrial, you see more 240 delta, with
> no neutral. Sometimes they ground the centertap of one of the feeder
> transformers, so that two of the legs are 120V relative to ground.
> 
> Then, you could connect the secondaries of the NST's in delta, with no
> problem, but I am not sure about the centertap (having been too busy to
> calculate it or try it)


It doesn't matter whether the primaries are connected in 
delta or wye;  Six phases will still result from the three
center-tapped NST secondaries, and therefore _none_ of the 
HT terminals can be connected directly together.

I chose a wye connection for the primaries in the example,
just because 120V primaries are more common than 208V ones.
-- 


-GL
www.lod-dot-org