Re: core saturation in variac

To: tesla-at-pupman-dot-com
Subject: Re: core saturation in variac
From: bigr-at-teleport-dot-com
Date: Mon, 17 Jun 1996 12:26:31 -0700

Tesla List wrote:
> 
> >From richard.craven-at-mkbbs.co.ukMon Jun 17 07:29:37 1996

> 
> I am struggling with the idea of using variacs as current
> limiting reactors.
> 
> 
> Today, I gapped all three of my variacs and I will remove
> the 250 turns of 22swg wire, and replace them with 100 turns
> approx. of 16swg (1.6mm diameter). 

I seems like it would be alot easier to buy a large iron core choke 
(20 lbs core or bigger) and make the gap adjustable with a brass screw 
in a hole that you tap out.  It would be an adjustable L: at L max you 
would have less current, but then saturation would not be problem- at 
low L you would get highest current, but most immunity from 
saturation.

Most of these cores are E| types so the | is easily removable.  I once 
used a big choke like this as a metal recording tape eraser :)   Fair 
Radio might be a good place to start looking for one of these- or some 
old linear power supply.

Best regards, Rob.