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Re: Dissolve Xfmr laminations



Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Heat might work... 

The real issue is that if you remove all that varnish (or whatever), you'll
have to put it back on when you reassemble. The reason it's laminated, as
opposed to a solid block of iron, is to reduce eddy current losses. 

Visualize the solid block of iron inside the winding.  Think of a thin
layer all the way around the iron (concentric with the winding).  It's a
shorted turn!. If you break the shorted turn, (i.e. by using a bunch of
thin plates, or wires, that are insulated), then you still have the iron,
but not the shorted turn.  Thin is good, and here's why.  Imagine if the
solid bar were broken into two halves lengthwise(along a plane parallel to
the center axis of the winding), insulated from each other.  Now you have
two shorted turns, albeit of half the area each.  Transformer design is a
tradeoff between thickness of the laminations (manufacturing cost, wasted
volume for insulation, etc.) and eddy current losses. The higher the
frequency, the thinner the laminations need to be to be effective.  A
powdered metal core or at higher frequencies a ferrite core is sort of the
ne-plus-ultra, but, comparing permeability, you can see that that silicon
steel transformer lamination is a lot hig!
 her than
the best powdered metal.  There's also a heat dissipation issue with
powdered metal or ferrite, since steel, while not a great heat conductor,
is a heck of a lot better than the plastic binder in the other cores.

Tesla list wrote:
> 
> Original poster: "Daniel Hess by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dhess1-at-us.ibm-dot-com>
> 
> Forgive me if this has been discussed on the list previously but does
> anyone know what will dissolve the stuff that they use to glue transformer
> laminations together with? I've recently come across two large power
> transformers that I want to disassemble and rebuild as a current limiting
> inductor for my pig.
> 
> The transformers look as if they were literally dipped in the stuff; Root
> beer color and is brittle. Chips off easily. I've tried acetone, lacquer
> thinner and mineral spirits but this stuff just laughs at these solvents.
> I'm tempted to invest in a five gallon pail of Berryman's B-12 Chemdip
> (carburetor cleaner) but I'd hate to invest $90.00 just to find that it
> won't work either.
> 
> My goal is to reassemble the laminations in an 'E' config with an 'I'
> plate, separated by a plastic shim to provide current adjustment.
> 
> Daniel