Re: Potato Chips (fwd) Laminations (fwd)

---------- Forwarded message ----------
Date: Thu, 30 Apr 1998 10:32:35 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Potato Chips (fwd) Laminations (fwd)

Hi Bill,

> Date: Mon, 27 Apr 1998 21:50:06 -0700
> From: Bill Noble <william_b_noble-at-email.msn-dot-com>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Potato Chips (fwd) Laminations
> As I understand it from years ago when I studied metalurgy, the laminations
> are to control the magnetc domains, not to eliminate eddy current.  If you
> look at a typical transformer, you have one secton like an "E", and another
> like an "I", so together they make an "8".  Many transformers have a thin
> sheet of insulator between the E and I, which I think does in fact eliminate
> eddy currents by preventing the shorted turn effect.  But if you look at the
> way the flux lines run (remember ILXB where "X" is the cross product) you
> will see that they don't cross the laminations.

That is precisely the problem. The induced currents are at right 
angles to the applied mag field. Laminations are definitely used to 
reduce eddy currents AFAIK. The basic principle is to reduce the area 
of parasitic shorted turns in the mag field to a minimum.