re: Xfmr laminations

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

Original poster: "Peter Lawrence by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>

Daniel,
    transformers are usually dipped in "Formvar" varnish, a heat curing rather
than air curing varnish (so that the varnish that seeps into the windings
will cure when the whole thing is tossed into an oven for a while).

I am not aware of anything that will take off varnish, but then why do you
need to remove it. There are two cases, varnish on the outside of the core
which should not be a problem removing or not removing, and varnish inbetween
the laminations which you need to leave in place.

The varnish inbetween the laminations has a purpose - to electrically insulate
the laminations from each other to reduce eddy currents and their associated
losses.

I'm in the process of winding my own transformer for TC use, reusing the core
from an existing xfmr. I chiseled off the globs of varnish on the outside,
and left alone the varnish inbetween the laminations.

Pete Lawrence.