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Re: Series-ing Potential Transformers



Original poster: dhmccauley-at-spacecatlighting-dot-com 

Actually it does work.  You need to series the primary (120VAC)  windings as
well.  I think you may be stating that you cannot do this with paralleled
primaries.
I have wired two 14.4kV PT's in series and have measured 28.8kV (across
output terminals) using HV divider.

Dan


 > No, this won't work.  In a NST one winding is wound in a different
direction
 > than the first winding.  This means that the outer end of one winding hits
a
 > 60 Hz positive peak as the winding wound in the opposite direction is
 > hitting the 60 Hz negative peak.  The peak to peak voltage is twice what a
 > single winding would be.
 >
 > In the case of 2 PTs hooked with a common center ground and each PT has
the
 > same winding direction, each PT would hit a postive peak and negative peak
 > at the same time so the output would not be twice what the single xmfr
would
 > give.  Each PT would hit 14.4 kV and then back to 0 kV as their phased
 > outputs would be exactly matched.
 >
 > You can try it, but unless you have a very strange PT this won't work.
 >
 > Dr. Resonance
 >
 > Resonance Research Corporation
 > E11870 Shadylane Rd.
 > Baraboo   WI   53913
 >
 >  > >
 >  > >Bert is correct. I have (2) butyl rubber 7200 volt PTs.
 >  > >One of them only has one HV bushing terminal while the
 >  > >other has two. As I mentioned in an earlier post re-
 >  > >garding this issue, I series the two together for 14.4
 >  > >kVAC out to my HV rectifier for up to 20 kVDC to charge
 >  > >my 10 kJ can crusher/quarter shrinker capacitors w/in
 >  > >20 seconds. I run the single bushing one from ground and
 >  > >take the "floating" 7200 volts off of the single bushing
 >  > >of it and run it "piggie-back" to one side of the double
 >  > >bushing one, making sure it's properly phased and get 14,400
 >  > >volts out of the second PT's second bushing. I have had
 >  > >no problems with this setup as I know the BIL rating of
 >  > >both of the HV terminals of the second PT should easily
 >  > >hold off up to 14,400 volts.
 >  > >
 >  > >David Rieben
 >
 >
 >
 >
 >