Re: Dissolve Xfmr laminations

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Richard Williams by way of Terry Fritz <twftesla-at-qwest-dot-net>" <richardwwilliams-at-earthlink-dot-net>

Daniel,

I quote:
"I expect to use some sort of varnish when I do the reassembly (Formvar?)"

If you locate the stuff let me know. I've been looking for it for some time
now.

As far as the welded bead I have no idea so that will have to come from
someone more knowledgable on the subject. Sorry.

Rick W
Salt Lake City

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, January 19, 2002 12:38 PM
Subject: Re: Dissolve Xfmr laminations


> Original poster: "Daniel Hess by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dhess1-at-us.ibm-dot-com>
>
>
> All;
>
> Several years ago, list member R. E . Burnett (Newcastle, U. K.) posted a
> website which contained photos of a custom built variable-inductor for the
> purposes of pig-limiting. Unfortunately, the website is no longer up**.
> The thing was basically a large 'E' core in which they'd installed a
> single-winding core, then topped with an 'I' core which when clamped
> together, formed a complete laminated core. Between the 'E' and 'I' pieces
> was a thin sheet of styrene creating an air-gap. By varying the thickness
> of the sheet styrene one could vary the amount current supplied to the
pig.
>
> This design has always impressed me with it's simplicity and elegance and
> since I was recently 'asked' to accept two very large (identical)
> transformers it seems that fate is pointing me in this direction. ( Isn't
> it wonderful when the knowledge of your hobby becomes so widespread that
> people start bringing you 'stuff'?)
>
> I'm not interested in the original windings; these things have a zillion
> secondary windings. I want to remove/discard these windings, disassemble
> the laminations then reassemble them as a big 'E' core and a 'I' core so I
> can (hopefully) do as R. E. Burnett did. Right now the E & I pieces are
> stacked alternately which forms the standard closed E core. I expect to
use
> some sort of varnish when I do the reassembly (Formvar?) but my original
> question is how to get the thing apart without destroying it hence the
> dissolve question.
>
> I notice that on two opposite corners they've run a bead (arc welded) the
> laminations together. I see this frequently on power transformers,
> presumably to keep the laminations from buzzing. But doesn't this negate
> the effect insulating the individual layers with varnish so as to reduce
> eddy currents, since the bead essentially connects them all together
> mechanically as well as electrically? At any rate, the bead is small and
> will not be difficult to grind off.
>
> Thanks for all the help thus far,
>
> Daniel
>
> ** It just moved - T.
> http://www.richieburnett.co.uk/tesla.shtml
>
>
>
>
> "Tesla list" <tesla-at-pupman-dot-com> on 01/18/2002 07:39:16 PM
>
> To:    tesla-at-pupman-dot-com
> cc:
> Subject:    Re: Dissolve Xfmr laminations
>
>
>
> Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <evp-at-pacbell-dot-net>
>
> Tesla list wrote:
> >
> > Original poster: "Loudner, Godfrey by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <gloudner-at-SINTE.EDU>
> >
> > Hi Daniel
> >
> > I would be concerned about stripping the coating on the laminations that
> > protects them from eddy currents. I have never had any trouble getting
> apart
> > the laminations with a butter knife once a few of them have been
removed.
> Of
> > course it might be very difficult to get out the first few laminations,
> and
> > the extraction might even destroy them.
> >
> > Godfrey Loudner
>
>  The oxide coating on the surface of each lamination provides the
> necessary insulation, and if the laminations are packed in as tightly as
> they should be the varnish won't penetrate the stack.  All along I have
> assumed the purpose of this discussion was just to get the laminations,
> and not try to use the existing windings.
>
> Ed
>
>
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