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Re: Inductive Ballasting

 * Originally By: Mrbarton-at-ix-dot-netcom-dot-com
 * Originally To: Richard Quick
 * Originally Re: Re: Inductive Ballasting
 * Original Area: UUCPE-Mail
 * Forwarded by : Blue Wave v2.12

From: mrbarton-at-ix-dot-netcom-dot-com (Mark Barton)
To: richard.quick-at-slug-dot-org
Date: Thu, 14 Sep 1995 01:46:38 -0600
Subject: Re: Inductive Ballasting

You wrote: 
>
> * Carbons Sent to: tesla-at-grendel.objinc-dot-com
>
>Quoting mrbarton-at-ix-dot-netcom-dot-com (Mark Barton)
>
>> I have had great success by winding large gauge stranded wire around 
a
>> 4 inch dia. phenolic or PVC tube about 3 feet long.  Close winding a 

>> few layers is usually enough.  A straight core is raised and lowered
>> in  and out of the tube by pulley means to regulate the inductance 
and 
>> hence the power draw.  It is almost impossible to saturate a 
straight 
>> core.
>
>Well Mark, Ed Sonderman and I were wondering if anybody else had tried
>this. It seems that three of us in the other group had happened upon 
the
>same idea, and in fact I posted the exact same dimensions as you just
>gave.
>
>For a core I had suggested buying a spool of bailing wire, then 
cutting 
>the wire into 3 foot lengths. The sections would be lightly coated 
with
>secondary sealer, tightly bound in a few spots with some friction 
tape,
>inserted into a 4" diameter ABS plastic tube, and potted with epoxy to
>prevent vibration. You can find four inch ABS and PVC pipe that will
>telescope fairly neatly, so the winding can be wound on the larger 
tube
>and can be coated with sufficient thickness of sealer to pot the 
winding
>to prevent loosening. Since we already had some resitive ballast in 
the
>circuit, and the arc welders pretty much opened up all the way, I 
figured
>one layer of winding would provide enough inductive ballast to do the 
job
>we needed.
>
>Questions:
>
>1) How much does your core weigh? so we have an idea of how many 
pounds
>of wire to purchase.
>

I have made 4 of these things over the years and the cores all weighed 
in at about 20-30 pounds.  Don't forget, all my coils are 10KVA 
minimum.  I used cannibalized transformer laminations from large 
transformers cut and lined up straight.  One time I used 2in by 3ft 
sheets of galvanized steel each individually wrapped in waxed paper.  
Another time I used a clump of welding rods each rod dipped in varnish.
Huh, huh, the varnish melted and ran.

>2) How many actual turns of winding are on the coil, and how many 
layers?
>

This varies with the amount of L you need.  The less power you want to 
run, the more L you need.  On the biggest limiter we built, we wound 4 
layers of #2 wire on a 4in by 3ft phenolic tube.  This was sufficient 
to run a 15KVA unit from full on with the core out, to full off with 
the core in.  Sorry, no data on actual number of turns.  Wind more than 
you need and then take it off if you can't draw the power.

BTW, Tesla and Golka both used this technique.  You can see the choking 
coil in the CSN photos.

Zap,
Mark

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