"Hmmm"!

I may be misinformed, but over my many years of working on and around ship
and docks, I would hear a loud humming sounds coming from "some" very large
transformers. The electricians would refer to this a "lamination hum" and
was often blamed on rust between the laminations which would increase the
gap between them.

It never seem to be a detriment to the performance of the transformer other
than an annoying noise.

I often wondered if it didn't, to some small extent, effect the efficiency
of the transformer.

Just my experience, FWIW.

Steve

"Christopher Tidy" wrote in message
...
Robert Swinney wrote:
Chris,

Why not just leave them alone? Conductivity between laminations is not
much of an issue in transformer and motor design. IMO, you'd do well to
put them back together again and make sure you have adequate protection
where the new wires will be in contact with the bare laminations.

Bob Swinney

Bob,

I might well do this. I just thought it would be nice to clean off the
rust as the dust makes quite a mess. But if I clean them, I want to do it
properly and then give them a fresh coat of insulating varnish. The
windings sit on a rubber/plastic former so that they aren't actually in
contact with the core.

Best wishes,

Chris