A follow up on my generator probem. I finally got time to take it apart
and found that the bearing at the brush end had worn out of round,
allowing the armature to rub against the field coil . . . There were
areas of abrasion on both. This no doubt started with torque on the fan
pully caused by the fractured tensioner bracket.
I pulled a bearing from a defunct generator I had laying around and
pressed it in, but only get a reading of 1 -3 volts. I guess I could
keep fiddling with this but it may be best to replace the generator and
be done with it.
From: Dave and Liz DuBois [mailto:email@example.com]
Sent: Monday, June 11, 2007 1:41 PM
To: Andrew Moyce
Cc: 'mg-t net'
Subject: Re: Generator problems
I doubt that the generator is bad, but here is a procedure for checking
the generator and if it is good, a quick check of the
Check the generator/dynamo by disconnecting the wires from its
terminals, connecting the two terminals together and to a 20v voltmeter
(analog meter, not digital). Start the engine - DON'T rev it!! - just
slowly increase the revs watching the voltmeter. It should get to 20v by
the time you get to 1000 rpm. DON'T exceed 20v. If that checks out
reconnect the wires to the dynamo with the voltmeter on the D terminal
(brown/yellow wire) and again start up and slowly increase the revs
watching the voltmeter. The voltage should rise then stabilize at about
14.5v, it goes higher again don't let it go over 20v. If it stabilizes
at 14.5v it is charging OK.
If the generator checks out good and the regulator is the culprit, I
would suggest contacting Bob Jeffers at: firstname.lastname@example.org and ask him
about changing your regulator to a sold state version. the cost is
about the same as a new regulator, but you get one that is calibrated to
the generator that you are using, that regulates much closer than the
mechanical ones and the case comes back buffed to a high shine.
Be sure that you don't over tighten the fan belt or you will damage the
generator - See my article regarding fan belt tension at:
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