"Fred McKenzie" wrote in message
...
Fred, how does the iron lose all its magnetism in the first place?
I thought that by design there was always supposed to be enough
residual magnetism to bootstrap the generator.

Asimov-

I don't know how, but it apparently happens on rare (?) occasion. Perhaps
the
earth's magnetic field happens to oppose the residual field due to the
orientation of the generator while in storage.

I once worked at a place where they made their own permanent magnets used
for
focusing an electron beam in a traveling wave tube. The field of these
magnets
was very critical for their application. They were sensitive to shock, as
I
recall. If one were dropped it would require re-magnetization or
recalibration.

The earths field is stronger than most imagine from everyday experience.
One can induce a weak magnetic field in a piece of soft iron (like rebar)
simply by orienting it north and south on it's long axis, and striking with
a hammer along that same axis. Afterward, the formerly unmagnitized bar
will have enough magnetism to pick up staples, iron filings and the like.

Maybe that's the solution for the OP: simply whack it (really hard) with a
hammer! Works for a lot of other things.... ;-)

jak


These magnets were "designed" to retain magnetism by virtue of the choice
of
the metal alloy. I don't think most alternators or generators use
anything
special, just iron. One of the references mentioned earlier, suggested
that a
small permanent magnet was sometimes attached to the iron just for this
purpose.

I looked at the manual for my Sears/Generac 3500 watt generator. There
was no
mention of re-polarization, and no permanent magnet was listed in any of
the
parts lists. It has sat idle for several years at a time, and when
restarted
has always delivered rated voltage. (I did have to replace the carburetor
once!)

Fred