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Simple alternator question

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bcbennett

bcbennett

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Is my TR6's alternator supposed to whine a little when I turn on my headlights? I can actually hear it as soon as turn them on and it quits when I turn them off. Is that normal?

I have been interested in the Bosch alternator swap mentioned on the forums (from the 1980 Ford Fiesta), and it may be time to do so.

Thanks
 
If it's "whining" it may need a regulator or the stator may be getting crud built up where the brushes make contact and you are not getting a full charge when needed (under load, with lights on). What is the output measuring with light off and then on?

If you decide to go with the Fiesta, here is the info:

https://www.74tr6.com/alternator.htm

Good luck!
 
You might also check that the thin bolts that hold the alternator together are tight.
 
A certain amount of alternator whine is normal when the alternator is putting out. The whine will get louder the more it puts out. That said, if there is a problem with the stator and/or the rectifier, it will whine louder then normal. Not being able to actually hear the whine makes it difficult for me to say whether or not what you're hearing is normal. However, a problem with a stator/rectifier will show up on your volt meter...the voltage will be lower then normal. I would think that with the lights on, you should see at least 13.4-13.6 volts minimum. Most times when a stator/rectifier has a problem, and the alternator is loaded up, the voltage will drop down toward battery voltage.
 
Art, it's possible they have all been defective; but from what I've seen, a stock Lucas ACR has lousy output at idle. Even a healthy unit will let the battery discharge slowly with the lights on at idle (meaning the voltage drops to below 12.6). That's one of the advantages of the Bosch unit, it produces much more current at idle.

I also wouldn't trust the dash voltmeter to distinguish between 12.6 and 13.6
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