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generator to alternator

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tinman58

tinman58

Jedi Knight
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I have installed the new supercharger and all is good!! Except... The alternator that came in the "kit"shows in the negative side of the amp gauge, until after about 50 miles it jumps to the positive side and charges about 15 amps for awhile. I have a battery charger that can do a diagnostic test on the alternator while the car is running. It says "Bad Alternator" it is a brand new Lucas alternator! " How can that be?" Is there a sure way to test the alternator other than removing the SC and all the other goodies to get at it?
 
Do you have the warning light on the dash hooked up? Some alternators need the current through the lamp in order to get 'started'.

My Ford alternator wouldn't start until around 3000 rpm with just the lamp, so I added a resistor across the lamp to supply more current. ISTR it was around 8 ohms @ 5 watts, but I could be mistaken.
 
The lamp is hooked up and stays off while the needle is in the negative side.
 
Weird. Does the ammeter swing "-" if you turn on the lights with the engine not running?
 
yes Randell way to the negitive side about 9-10 amps. I think it might be the regulator in the alternator that is intermittent.
 
Yup, sounds like it.

If it's any consolation, the alternator on the wife's Toyota died and it took us SIX "new" alternators (probably actually rebuilt) to find one that lasted more than a month. Fortunately my FLAPS covered them under warranty, and they're easy to change on that car.
 
Well pulled out the supercharger to get to the alternator. not so much fun! I took it to the local flaps and told them it is from a triumph... "A WHAT?" no codes or numbers in their computer. I think it is a delco DRA 0790. Tomorrow I will take it to the local auto eletric shop to see what is up.
 
The alternator in my kit was a Lucas 18ACR.
 
Larry's auto elet. did a check and found a bad regulator in the alternator . 10 minutes and a couple bucks. Reinstalled the alt. and the supercharger and I have a working alternator!!
 
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