RE: Wiring NSTs in anti Parallel

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Original poster: Thomas <tom-at-pwrcom-dot-com.au> 

 > Original poster: "tmoorezz" <tmoorezz-at-adelphia-dot-net>
 >
 >
 > Hello all, I just got a quick question, I have two 7.5/6ma
 > francformers, I
 > want 15kv out of those two at 900 watts and up. Now if I
 > depot the two
 > transformers and wire them in anti parallel will this work if
 > I keep the
 > nst cores isolated I tried this once before and got some bad
 > results, there
 > was arcing between cases. I just wana know before I go and
 > depot two nsts
 > cause its a big hassle, and id rather not do it, but will, if
 > this will
 > work. Heck I just might go for it and purchase a pole pig, I
 > am sick of
 > messing with nsts and mots! Thanks!
 >
 > Nolan Moore
 >

What is anti-parallel?

Wiring the primaries in parallel and the secondaries in series (with correct
phasing +mmmS1mmm-+mmmS2mmm-)* will give you 15kV. BUT...

Depotted as you describe, and even if you can disconnect the secondaries
centre taps from earth and earth the join between the two secondaries
instead, you may still have breakdown problems.

The NSTs were designed for +/-3.75kV max between the secondary windings and
the core, primary winding, and chassis. You will now have +/- 7.5kV.

The only sure way to get 900W out of the two NSTs is wire both the primary
and secondary windings in parallel, and to leave the centre taps earthed.

Again make sure you have the correct secondary phasing (+ to +, and - to -
in this case)*

Unfortunately this will give you 7.5KV/120mA, not 15kV/60mA

Tom L.

* Obviously these polarities reverse 50/60 times a second, but stay relative
to one another.