Re: Balancing chokes

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Sparktron01@xxxxxxxxxxx 

Chip, all

I'm late entering this thread.  I'm helping a fellow experimenter 
build a very large ~25kVA Variac stack
using 3-1256D's (28A, 240V).  The proper connection diagram for up to 
(8) variacs in parallel using
balancing chokes is shown in attached URL.

http://www.superiorelectric.com/PDF/Z50pwst.pdf

See page 3 of 8, connection 3 (P/N MB1256D-3P, 0-240VAC, 28kVA, 84A 
@100% DC).  He has a
 massive Stack of 2 x 8 motorized variacs capable of well over 
100kVA nameplate, will use
 equalizing chokes from that assembly.  Motor with traverse 0-100% 
in 30 secs.  Notice the balancing
chokes are wired on secondary side in series, reflected impedance 
forces current balance on
entire assembly.  Keep it simple, and smile doing it... :^)

Also on a large Variac stack like this, use a series current limiting 
resistor and contactor ("step start")
to limit inrush current (could approach 500A on a system like this).

Regards
Dave Sharpe, TCBOR/HEAS
Chesterfield, VA. USA


 -------------- Original message ----------------------
From: "Tesla list" <tesla@xxxxxxxxxx>
> 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
>
>