Hey All,

Anyone ever heard of an issue with the voltage meter dipping very low when rpm's reach over 2300? I passed a semi on the highway yesterday, and when I dropped it down a gear, and got past mid 2000 rpm, the meter dropped and the battery light came on... Checked the battery and altenator at the store, and both are good. Any idea's?

 

I Heard from a friend that it might just be a voltage regulator. After installing the new part, nothing changed. Any help would be greatly aprreciated...

 

I have seen alternators cause this issue before, even though they check ok.

 

Acomplete test of the alternator would consist of:
[ul][*]rotor continuity[*]stator continuity[*]full field test for maxmium power output (980W for 70A)[*]maximum output power under full load (70A)[*]voltage regulator set point (14V)[*]voltage regulator set point hot (temp compensation)[*]cut-in speed (indicator lamp out)[*]output waveform[*]ripple voltage @ maximum output[*]rectifier diodes voltage drop and forward current tests[*]rectifier diodes leakage current tested at 12 volts [/ul]
Of course, since the test is free, they tend to only do the minimum test which is a Full Field Test.

You could have a worn set of brushes in the alternator that loose contact as RPMs increase. This is just a guess since you don't state how many miles are on the vehicle. But on average, 1997 would have about 150,000 miles. The normal life of a set of brushes is about 125,000 miles.