[Amps] HV transformer and Variac

[Robert Arenella]

> ## The difference between the hypersil pole pigs and say the dahl plate xfmrs is... on the pole pigs,
> the primary is the 7200 vac winding.... which is called the primary.   The primary always goes on the inside
> of the core..with the secondary wound on top. Sec of course is the   240 /120 vac side.

       Do a bing search of "How It's Made: Pole transformers" and you 
will see that the low voltage side is wound first, with the HV winding 
wound over the LV winding.  The neutral side of the HV winding is wound 
closest to the primary winding for safety reasons.

       I have a 14.4 KV pig that I'm going to use for a rather large 
Tesla coil.  It is wound as described above.  It also has taps on the HV 
side for 12.8 KV & 13.2 KV.

       For amp use, look for a Superior electric 1256D Variac.  0-280VAC 
@ 28 amps continuous. For intermittent operation, you can easily draw 
twice their rated current & they just get a little warm.

       I have one that I use to power a very large X-Ray transformer 
powered Jacobs ladder.  The transformer is rated at 0-300 VAC in, 125KV 
@ 300 mA out. The filament transformer & diode stacks were removed & 12" 
porcelain insulators replaced the federal plugs.  I run it at 280 V out, 
with the primary of an arc welder in series with the primary of the 
X-Ray transformer, for current limiting.  It draws 56 amps @ 280 V.  The 
core of the variac gets moderately warm after a 1 minute run.   Arcs are 
from 24" - 30"....Lots of fun on Haloween.

73,
Bob
N2OAM