Re: Balancing chokes

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "huil888" <huil888@xxxxxxxxxxxx>

I think many people may be off on a tangent here, not understanding the
function of "balancing chokes". Actually, the "balancing chokes" supplied
by the variac manufacturers are 1:1 ratio transformers, not just simple
inductors. These are interconnected in a "buck/boost" configuration to help
equalize the output current of paralleled variacs. Calling them 
"chokes" is misleading.

Even with the use of these balancing chokes, the variacs need to be 
very carefully mechanically synchronized on their common shaft to 
assure that all variacs are supplying (as close as possible) the same 
output voltage. It may be best to perform this synchronization at the 
full output position, rather than at the zero output position.

Simply inserting an inductor in the output leg of each variac will do 
nothing to equalize the current supplied by each variac; likewise, 
winding three inductors on a common core and connecting each winding 
to an output will do nothing either (except snub current spikes 
caused by sudden load variations).

Regards,
Scott Hanson
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, November 28, 2006 10:52 AM
Subject: Balancing chokes


> Original poster: <chipford@xxxxxxxxxxxx>
>
> Could I wrap say 10 or 12 turns of #8 or #10 wire (2 strands) on (3) of
> these and use them as balancing chokes for my (3) gang variac? Or would a
> toriodal shape be more appropriate? Thanks for any and all input...Chip
>
> http://hot-streamer.com/temp/siiron.jpg