Re: Potato Chips (fwd)

---------- Forwarded message ----------
Date: Mon, 27 Apr 1998 08:22:04 -0400
From: Thomas McGahee <tom_mcgahee-at-sigmais-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Potato Chips (fwd)

That coating on each lamination is there for a reason. If you do remove
it, remember to re-coat before re-assembling. You don't want the
laminations making a good electrical connection with one another
because that will just increase the eddy currents, which is what
laminating the core is trying to reduce in the first place. 

Core laminations usually have a bluish or blackish coating that is
very thin that helps prevent eddy currents from flowing "sideways"
from lamination to lamination.

The purpose of the varnish is to help hold the laminations
together and prevent excessive hum. 

Hope this helps.
Fr. Tom Mcgahee

> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Potato Chips (fwd)
> Date: Sunday, April 26, 1998 11:55 PM
> ---------- Forwarded message ----------
> Date: Sun, 26 Apr 1998 05:08:25 -0700 (PDT)
> From: gweaver <gweaver-at-earthlink-dot-net>
> To: Tesla-at-pupman-dot-com
> Subject: Potato Chips
> The laminations on one of my unpotted neons is out of square.  The thing is
> twisted looking and I don't like the way it looks so I took it all apart.
> The laminations were stuck together with something like varnish or
> polyurethane.  I decided to sand blast the laminations to remove the
> varnish.  When the sand hit one side of the lamination it instantly curled
> up like a potato chip. The varnish came right off.  I turned the lamination
> over and sand blasted the other side and the metal instantly curled up in
> the other direction.  I tried to straighten it out by sand blasting back and
> forth a little on each side but it won't straight up. I tired hammering it,
> but its still not flat.  I tried 3 more laminations and they did the same
> thing.  There must be some type of stresses in the metal that cause this to
> happen.  WARNING, don't sand blast transformer laminations. Acetone takes
> the glue stuff off of the lamination with no trouble at all.  Just let the
> lamination soak about 15 minutes.  You don't even have to wipe them clean
> with a rag.
> Gary Weaver