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Re: [TCML] pole pig question

--- Jim Calvin <jcalvin@xxxxxxxxxxxxxxx> wrote:

> Hi guys,
>I am trying to test my 25KVA  pole pig.


> I have a .05uF (at 50KV)
> capacitor connected to the HV output of the pig as a
> test load. One of the
> HV outputs is connected to GND along with the pole
> pig can.


Why are you using a capacitor as a test load?  It's a
reactive component that consumes zero power, so it
isn't really a "load" at all.  Also, it could achieve
60Hz resonance--a potentially fatal condition for your
capacitor or pig (depending on which one fails

Many years ago (before I knew better) I attempted to
"test" a 15kv/30ma NST using a 6nF wine bottle cap as
a test load.  To my amazement, the NST produced sparks
that went AROUND the ceramic HV bushings to reach the
NST jacket--a tracking distance of nearly 3 inches!  I
had unwittingly discovered AC line frequency
resonance.  Fortunately, one of the wine bottles
punctured within a second or two, saving my NST from

A power resistor is a much more sensible dummy load. 
If you use a 1000 ohm resistor in parallel with a
voltmeter, then AC volts on the meter = AC mA thru the
resistor--a far more useful indicator of pig
performance.  Watch the power rating though.  If your
voltmeter indicates 300VAC across the 1k load
resistor, that means it is passing 300mA.  That's 90W
the resistor must dispose of.  Fortunately, 100W
ceramic, wire-wound power resistors are fairly common
surplus items on e-bay.

If a fat 1kohm unit is too hard to find, then
substitute almost any low-value, high-wattage power
resistor or even a tungsten light bulb.  A standard
60W bulb makes a fine load resistor that reaches full
brightness at about 500mA--a convenient, if crude,
indicator of pig current.

BTW--have you tried just using a spark gap to test
your pig?  Even that would be preferable to a


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