RE: Ballast choke

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

Original poster: "Godfrey Loudner" <ggreen-at-gwtc-dot-net> 

Hello J

Ignoring the resistance of the winding, we can estimate
by using ohm's law I = V/R, with R the inductive reactance
R = 2(Pi)fL.

120/(2xPix60x0.015) = 21.2A,

120/(2xPix60x0.020) = 15.9A,

120/(2xPix60x0.037) =  8.6A.

This looks close enough to your chart. I don't know the
design voltage of the inductor. If you apply more than the
design voltage, the core may saturate. If the design
voltage is for 120V or more, you should be okay without
gapping the core.

Godfrey Loudner

 >I was given a large inductor the other day that has three taps of 15,
20, and 37 mH. (measured >with LCR-55).  It's quite old, and is wound
with a square wire of 1/8" cross section onto a
 >wound core of thin metal with a cross section of about five square
inches within the windings.

 >A chart from the list that I saved several years ago indicates that
with 120 Volts applied, it >would limit the current at 9, 16, and 21
amps, depending on the tap used.  Does this sound
 >about right, and would it be OK for use as a ballast, even though the
core isn't, and can't
 >easily be, gapped?

 >Weazle