Re: More Tuning/Debugging Next

To: tesla-at-pupman-dot-com
Subject: Re: More Tuning/Debugging Next
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
Date: Mon, 9 Sep 1996 08:09:05 +1200

Hi Bert, all,

> I was just reading a section on distribution transformers in a book
> called "Electrical Power Technology" by Theodore Wilde (John Wiley &
> Sons, 1981). The discussion on the no-load saturation curve for these
> transformers says that transformers are usually designed to operate at a
> peak flux density of about 1.5 Tesla, which roughly corresponds to the
> knee of the saturation curve. This implies that, even with no load, the
> primary current will rise dramatically once we begin to apply any
> significant overvoltage to the winding. "We can exceed the nominal
> voltage by perhaps 20%, but if we apply twice the nominal voltage, the
> exciting current may exceed the nominal full load current, even when the
> transformer is not loaded". This sounds exactly like the situation a
> number of coilers are using:  overdriving the 120 volt winding(s) to
> push a 6-7.2 KV pig to a higher output (12-15 KV). 
> 
> Have any coilers actually measured the pig's primary current draw with
> NO output loading versus input voltage??  If the pig is heavily
> saturating, will this tend to improve or worsen the transients created
> by the inductive ballast when the gap extinguishes?? 

That is exactly the trick I used to boost the output of the 
transformer for my work coil. With a 500 turn primary, the magnetizing
current was around 0.5A. With a 450 turn primary, Imag went up to 5A+.

Malcolm