Current Limiting Queries
From: FutureT [SMTP:FutureT-at-aol-dot-com]
Sent: Thursday, January 22, 1998 10:33 PM
Subject: Re: Current Limiting Queries
In a message dated 98-01-22 10:54:02 EST, you write:
> Lastly, can a pole pig be current limited by means other than an arc
> welder or series power resistors?
The welder makes an excellent current limiter. Another way to
make a ballast is to wind about 150 turns of #10 wire on a 3" PVC
pipe about 14" high. Tap the coil every so often and connect these
tap points to a rotary switch. Then fill the center of the pipe with
welding rods and/or threaded steel rods to create a steel core. I've
used this type of ballast on pole and potential trannies with good
results. An improvement would be to build a device that can raise
or lower the core to smoothly vary the inductance.
Another method is to use a variac as a current limiter, but this
requires cutting a slot in the variac core to prevent saturation.
I don't like resistive current limiting because it wastes so much
power. Many coilers find that the addition of some resistance
in series or in parallel with their inductive ballast smooths the