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Larry Larry is offline
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First recorded activity by BoatBanter: Jul 2006
Posts: 5,275
Default How Hot should an alternator get?

"GBM" wrote in news:caXtg.46517$Uy1.96
@read1.cgocable.net:

Should the alternator run that hot?


Sure. They're not 100% efficient. The core heats up from the magnetic
loading, the windings with 100 amps going through them heat up because
they are wound so tight. It'll smoke if it gets too hot and the windings
will turn black. The rectifier diodes mounted to the case to cool them
also make the case quite hot. The diodes can withstand 10 times what
your hand will fry, too.

Would low speed caused by slipping belt cause overheating?


A belt slipping over a steel pulley gets REALLY hot. Lots of heat is
transferred from the pulley to the rotor bearings on the pulley ends,
heating the case of the alternator, I presume.

If not, what could cause be? Or is it normal?


If it's not smoking or smelling like it's cooking insulation, it's
normal.

Test this in your car. Start your car and turn everything on, especially
headlights and air conditioning fans wide open. Drive to the store.
When you get there, shut down the engine, open the hood and see if the
alternator is hot. Don't get burned and blame me, ok?


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