Re: Ballast Current Setting

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Mike,

Not sure how to answer your question but maybe I can give you some insight.

If you short your ballast to ground and adjust it to limit the line 
current to say 15 amps, you will probably see more than 15 amps in TC 
service.  The reason for this is the capacitive load your PT is 
driving will reflect to the primary by N^2.  Other words, Cp will 
look N^2 times larger (lower impedance) on the primary side and its 
reactance will cancel to some degree the ballast inductive 
reactance.  Hence, the current limiting effect of the ballast is 
altered somewhat.  Worst case senerio is a Cp value that resonates 
with the ballast and "perfectly" cancels the reactance of the ballast.

Gerry R.


> Original poster: "MIKE HARDY" <MHARDY@xxxxxxxxxx>
>
> My 6" coil is the first one using a variable ballast to set current 
> on the line side of my PT. I found amperages with a current xfmr, 
> and meter. output was jumping a sparkgap, that's all. I set the 
> current for what my Cp required. When  monitoring my actual coil 
> this current had jumped from 15A to between 22 and 25A. Should I be 
> adjusting the curent for the actual coil, or my initial way ?