Re: transformer lamination

To: tesla-at-pupman-dot-com
Subject: Re: transformer lamination
From: Jim Fosse <jim.fosse-at-bdt-dot-com>
Date: Sat, 08 Feb 1997 06:46:10 GMT
Cc: major-at-vicksburg-dot-com
Subscriber: jim.fosse-at-bdt-dot-com Mon Feb 10 21:32:20 1997


>Subscriber: major-at-vicksburg-dot-com Fri Feb  7 00:39:27 1997
>Date: Thu, 06 Feb 1997 23:23:10 -0600
>From: RODERICK MAXWELL <major-at-vicksburg-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: transformer lamination
>
>I have completely cleaned up and reassembled the core of the first of
>four neon transformers that I got from a sign shop in town. after I put
>it back together I checked the isolation between laminations with an ohm
>meter. And lo and behold they read low resistance. I'm not an electrical
>engineer like some of you fellas but even I know that there should be
>some sort of insulating coating between the laminations to cut down on
>eddy cuurents! Are neon cores supposed to be this way? The only thing I
>see on the laminations is some sort of metal blueing. I guess this is to
>keep them from oxidizing, I have taken appart other cores and they all
>had varnish applied. I wonder if it would hurt to apply some varnish?
>Any suggestions, or answers would be welcome! 
>
Hi Roderick,
	I are an engineer;) and I was going to jump up and down and
yell VARNISH it!  But, before I put my foot in my mouth and bit down
hard, I thought that I would look/measure my unpotted (freezer method,
I did not use solvents that would have dissolved any varnish) neon
core.  It's core is not varnished.  The laminations are shorted to
each other by contact!

I would not have believed how poorly neon sign transformers are made!
Core laminations that are not insulated. Cheep (lowest grade possible)
secondary insulation. Undersized wire.  I no longer wonder why they
blow out in TC usage.

I would say "go ahead and varnish it" except that I'm concerned that
if the varnish is to thick, you will not be able to get the windings
back on the core.

	Regards,

	jim