2v sounds about right for the voltage generated due to residual magnetism.
What should happen is that voltage is fed to the field winding, which
increases the strength of the magentic field the rotor is spinning in, and
it then generates the full voltage. You can check the generator by removing
the two connectors from it and bridging the two terminals on it (the
generator) together, and connecting a voltmeter between them and ground.
Start the engine and slowly increase the rpm. You should see 20v by the
time it reaches 1000 rpm, do not exceed 20v. If this checks out then the
dynamo is OK so it's time to move onto the wiring and control box.
Make sure your D terminal on the generator is connected to the D on the
control box and the F to the F. What should happen is that the control box
bridges these two terminals together, then as the voltage rises it operates
the cut-out at about 13v, which connects the output of the generator to the
rest of the car and starts charging the battery. When the battery is fully
charged, or if the charging current exceeds a certain amount, the voltage or
current relay as appropriate operates to limit the charging voltage/current.
Hopefully that should be enough to help you track down the problem with your
voltmeter.
PaulH.
http://freespace.virgin.net/paul.hunt1/
-----Original Message-----
From: Parker J Whiteway <parkerw@juno.com>
To: mgs@autox.team.net <mgs@autox.team.net>
Date: 17 July 1999 15:16
Subject: MGA Generator Problems
.>... Now, I start
>the car up and the ignition light won't turn off. My ammeter stays at a
>little below 0 amps (it used to work too) and when I test the DC volts at
>the large terminal on the back of the generator, I can't get more than
>about 2 volts, at any engine speed.
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