Re: IS 240VAC two-phase - NO

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > Original poster: "Ian McLean" <ianmm-at-optusnet-dot-com.au>
 >
 >  >  In a 15K
 >  > NST,
 >  > if we want 7.5K to run a small coil, what do we do?  Utilize one high
 >  > voltage bushing (one half of the windings) for a hot, and the case,
 >  > which
 >  > again is connected to the center of the huge secondary, as a neutral.
 >  > Want
 >  > double the voltage?  Run off of both bushings for the full fifteen
 >  > grand.
 >  > Same with a distribution transformer.
 >  >


 > Or so I have been led to believe ...
 >
 > I believe the opposite is also true.  You can completely short an NST's HV
 > bushings to each other or the centre tap.  The tranformer will get warm but
 > will survive because it is current limited.  I have even heard of people
 > running NST's this way for a few hours to help heat up the bitumen potting
 > to help remove it :-o

	I ran a 9 kV, 60 ma transformer for about 12 hours/day, 365 days a
year, for a bit over three years with one side of the secondary
shorted.  Got a bit warm but no problems of any kind.  The service was
in the "skunk zapper" which was mostly unloaded until some beast got
across the wires.  Actually, because of the capacitance to ground of the
fence, the voltage actually rose a bit when it was connected.  So both
conditions at once.  One side open and one shorted and no problem.

Ed