ampmeter goes crazy

F

fomocoloco

Senior Member
My stock 36 has a 6 volt neg. ground alternator.
Driving down the road, the ampmeter acts normal. When I switch on the electric fan or the headlights, the ampmeter goes crazy. I've had the alternator for a year. What is my problem?
 
Possible loose connection where the wire connects to the alternator. Make sure the nut is tight.
 
The alternator makes ac and rectefies to dc dirrect current.
I can,t even think of any car with alt that uses a ampmeter.
Your output to battery with higher current is more knowable.
Better off with voltmeter.
If you went with 12 volts, seeing you have neg grd ,higher voltage is less current.
 
George/Maine


I have installed dozens of 10Si alternators with SW ammeters that worked good on equiptment.

Bruce

Works good
Lasts long time
 
I'd certainly lean toward a loose connection somewhere. As previously mentioned, check the wire coming from the alternator first then start tracing wires. Have you made any changes, additions or repairs to the electrical system recently? Many times, the best place to look for a new problem/symptom is the last place you worked. Good luck!
 
George/Maine said:
The alternator makes ac and rectefies to dc dirrect current.
I can,t even think of any car with alt that uses a ampmeter.
Your output to battery with higher current is more knowable.
Better off with voltmeter.
If you went with 12 volts, seeing you have neg grd ,higher voltage is less current.
Click to expand...
I've had an alternator on my 40 i2volt with an ampmeter for35 years. I like an ampmeter better than a volt meter, It tell me what differrant things draw. Like when I turn on the electric fan it draws 15 amps. When I first start the car after setting a few day it charges why over and as the batt charges up it just charges a little. All a volt meter tells me is how may volts is in the batt. And I want to say too. blarrrrrr lol Walt
 
I see they sell a 6 volt alt kit and is a one wire kit.
I would say the alt is not working correct.
The alt isn,t putting out a even dirrect current.
I had a diode go out on my 12 alt and made my electric fuel pump noisy.
Re check your wiring and grds.
 
I had the same problem on a Packard, was pulling the gen when I noticed a little smoke coming from the inside of the frame. Turned out the wire going to the gen cutout went thru a loop type bracket bolted to the frame and the insulation had fallen off. There was enough crud, old caked grease around it to not have a dead short, just a jiggle sort of short.
 
I'd suspect a jumpy ammeter is caused by:

1. An intermittent short like a bare wire touching ground.
2. A dead short that is rapidly tripping a circuit breaker.
3. A bad voltage regulator that is rapidly cutting in and out.

Considering that it happens with EITHER the headlights OR the blower, I'd look at replacing the regulator.
 
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