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Re: Polepig use...

In a message dated 96-08-03 02:57:20 EDT, you write:

<< 
 Hi Ed (all).
 
 This is mostly to Ed Sonderman, but anyone who have some good input 
 might write as well.
 Seems to me that You(Ed) and i have quite similar coils and just wondered 
 how you have setup the polepig you're using. I soon have two or more "pigs"
  in my posession. 
 They are from a closed down railway track(service transformers) and i guess 
 i can get a bunch of these for little or no money at all.
  Anyone ever used these transformers by the way?? The input on these are
 about 16kV and out 220V. 
 I'm planning to use them backwards so my output will be about 12-13kV. 
 That way i don't need to construct so "big" caps. 
 How do you use the welder, "resistors" etc.... ? Some schematics of 
 different setups would be very interesting to see.
 I might need some reply to this since we are talking serious power.
 Don't want to fry something.
 
 Also when you(American and other 110V countries) people say you use 
 220V where do you get it from?? Is it singele or polyphase? If 
 polyphase how do you make the connections to a single phase 
 transformer??(as i'm planning to use, suspects that your polepigs are 
 single phase too)
 Anyone have some specs for a, let's say 10kVA polepig at 14,4kV.
 . I suspect that i'm not 
 the only one who have tons of questions about the use of polepigs.
 So please fill us "neonsign xfrmrs-soon-to-be-polepig" users in on 
 this, as there seem to be many of you using them.
 Keep up the good work. 
 
 //Matt >>

Matt,

Neon sign transformers are internally current limited so you can use them
with no external limiting device and they work great with static spark gaps.
 For using pole pig transformers with Tesla coil systems, you will need to
use some means for limiting the currrent into the primary of the pole pig and
you also need to use a rotary spark gap.  A normal static gap won't quench
the much larger currents that are available from a pole pig.  I use a
standard cylindrical gap (electrically folded in half) in series with a
rotary gap.

Pole pigs can be current limited by resistive means but you loose a lot of
voltage across the limiting resistor and it doesn't provide very good
control.  A large variable inductor works best.  You can build your own or do
what most of us do and use a 220 volt arc welder.  This is connected in
series with one leg of the 220 v input to the pole pig.  Richard Quick
suggested to wire the welder in series with the input to the variac which I
like and is how my system is wired.  The secondary leads (welding leads) of
the welder are shorted together.  Now you control the maximum output current
of the pole pig by adjusting the variable core in the welder.  Set at the
lowest setting will provide minimum currrent out of the pole pig.  You might
want to experiment with some low value of resistance in either series or
parallel with the welder to get the smoothest control.  I had been using
three 2000 watt oven elements in parallel with the welder until I changed my
primary wiring between the cap, gaps and primary.  Now I am using the welder
directly with no other resistance.  I need to do some more experimenting with
my system in this area.

The standard power delivered to households in the U.S. is 220 volts AC with a
neutral line to provide 110 volts AC between either hot line and neutral.  It
is single phase power.  The specs on a 10KVA  14,400 volt pole pig are just
that, it will deliver 14,400 volts ac with 220 volts in at 10kva - which is
about 700 milliamps out.  This transformer will deliver twice that much
current for several minutes at a time without even getting hot.  I suggest
you set up the primary power system with an ac current meter so you can
monitor the primary currernt.  You will need a 0 to 50 or maybe 0 to 75 amp
meter.

Good Luck,  Ed Sonderman