Re: Chokes

To: tesla-at-poodle.pupman-dot-com
Subject: Re: Chokes
From: Tesla List <tesla-at-stic-dot-net>
Date: Wed, 26 Mar 1997 23:18:51 -0600
Approved: tesla-at-stic-dot-net
Subject: 
        Re: Chokes
  Date: 
        Wed, 26 Mar 1997 21:21:01 -0500
  From: 
        "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
    To: 
        Tesla List <tesla-at-pupman-dot-com>


> Date:          Mon, 24 Mar 1997 21:59:24 -0600
> To:            tesla-at-poodle.pupman-dot-com, tesla-at-poodle.pupman-dot-com
> Subject:       Chokes
> From:          Tesla List <tesla-at-pupman-dot-com>

> Subject: 
>         Chokes
>   Date: 
>         Mon, 24 Mar 1997 16:50:57 -0800
>   From: 
>         Gary Weaver <gweaver-at-earthlink-dot-net>
>     To: 
>         tesla-at-pupman-dot-com
> 
> 
> I need some current limiting for my 16,800. watt transformer.  Will
> choke 
> transformers work in place of an Arc Welder?  I have a Lincoln welder I
> can 
> use but I found several very large choke transformers at the scrap yard 
> today. The smallest one is wound with #6 square copper wire.  There are 
> several of these large chokes. 3 small ones, 2 medium size and one large
> one 
> that probably weighs about 400 lbs.  Will these work for TC current
> limiting?
> 
> Gary Weaver
> 
> 
Gary,

Chokes or reactors as they are known when used to limit current are 
perfect for this function in a Tesla power supply with a pole pig in 
lieu of an arc welder.  Sounds like the wire size in the one you just 
described is perfect for up to a 10 kVA or so pig powered system, but
these 
sound so physically large that they may actually have too much 
inductance.  If this is the case they can be tapped down or windings 
can be removed.  I believe you can also change the inductance by 
changing the air gap spacing between the E and I sections (if your 
core is this type) although I have never tried that yet.  I never use
more than 
about 10-15 mH of control ballast and usually use 5-7 mH with no
resistors,
but I haven't yet done any coiling above the 10 kVA level.  Up there 
I'd probably use less.

If the small ones are at least 50 lbs each and are wound with #6 
square wire I would definitely at least grab those.  Take an L meter 
with you and check the others.  If they are also wound with #6 or 
larger wire and priced right I'd grab those too, even if they are too 
high in inductance.  These are hard to come by and could have other 
uses later, or good swap value.  They also make *terrific* paper 
weights, door stops,  boat anchors, and ballast weight in the back of 
the pickup truck in winter!

rwstephens