Re: Escort alternator bad?
The slip rings can be slightly out of round.... if the brushes stick
slightly in the holders, they can be able to follow the slip rings at low
rpms but "float" at higher rpms.
Given the age of the car, I would probably opt for a good quality rebuilt...
If finances are a concern, there is a chance of success in replacing the
brushes and cleaning carefully. Having alternator ripple tested at low rpm
may uncover failing diodes that may colour your decision. If you have a
decent DMM, you can test for ripple using the AC 2 volt scale.... Start the
engine and turn on all the accessories to load the charging system.... with
the DMM on the AC 2 volt scale, attach one probe to a good chassis ground
(not to the battery) and the other probe to the output terminal on the
alternator. Ripple voltage should be below 0.5 volts.
"fordfan" <email@example.com> wrote in message
> I have a 94' Escort with the 1.9 engine. The alternator/battery charging
> light has been coming
> on, but only when the engine speed reaches about 2000/rpm. It goes out
> when the RPM drops below 2K. The headlights dim a little when the
> warning light is on. They get brighter when the light goes out. This
> would seem to indicate that the alternator is not charging above 2K-RPM.
> I don't think the drive belt is slipping. There aren't any noises
> either. Suggestions?