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Voltage Regulator Test?
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Author:  B-nuts [ Wed Oct 25, 2006 10:53 am ]
Post subject:  Voltage Regulator Test?
Is there a way to test a voltage regulator to see if it's working? I put a squareback alt and a 'new' style VR into my 65 barracuda, wired according to a diagram from somewhere, and the ammeter isn't going above the middle now. Not that it ever did, but my battery is dying now. The ammeter is about have way into the draw side when lights are on. That's the only electrical draw I have besides the engine. Also, is there a difference between the two fields on a squareback? It seems one would be + and the other -, but it doesn't say on the back. How could I figure that out? Could that be my problem?

Thanks for any help in advance[/img]
Author:  B-nuts [ Wed Oct 25, 2006 11:40 am ]
Post subject: 
One other thing, it doesn't seem to matter whether the fld wires are plugged in or not. I tried every combination of grounding the fld terminals and no change in voltage occured, does this mean the alternator is shot? It was running 11.85 volts with no load and 10.25 with lights and wipers on. Doesn't seem to be much charging going on there....
Author:  Pierre [ Wed Oct 25, 2006 12:01 pm ]
Post subject: 
It doesn't matter which field wire goes to which terminal on the regulator. But on the regulator with the triangular connecter, its the upper terminal that gets switched +12v.

Most parts stores will test your alternator for free.

Don't run your battery too long at 10.something volts, unles your looking for an excuse to buy a new one.
Author:  B-nuts [ Wed Oct 25, 2006 12:24 pm ]
Post subject: 
The 12v was wired to the wrong side. Thanks. Could I have fried my VR like that? It won't engage the alternator, but if I bypass it by grounding the outside wire on the VR, it will charge at aroung 13.25v and a distinct sound can be heard from the alt brushes or something in there. Only I know I can't just run around town like that because I'll blow up the battery. Could I have blown the Regulator?

Thanks
Author:  Pierre [ Wed Oct 25, 2006 12:55 pm ]
Post subject: 
Noise from the alternator doesn't sound good....

To test the alternator independent of the regulator completely, take one field wire to + battery, one to - battery. Don't do this for too long and do it only at idle. With no load besides the engine, you should easily get 14+v with a healthy battery and alternator.

I have a feeling you may of already killed the battery, or it needs charging outside the car.

Do the full field test and if you get good voltage that way, and you already wired the regulator up right, then yes you may of poped it.
Author:  LUCKY13 [ Sun Oct 29, 2006 6:34 pm ]
Post subject: 
The noise you hear is perfectly normal, it is just the alt charging. But it should of put out more like 17.5 volts when you grounded the wire to full field it. Maybe your battery is so low it would take a little wial to build up to that. I guess its possible you could of fried the VR when you hooked it up backwards. But make sure the VR itself is grounded to the body, it cant regulate without its body having a good ground.


Jess
Author:  KBB_of_TMC [ Tue Oct 31, 2006 12:30 pm ]
Post subject:  voltage regulator test
The VR can be tested on the bench using variable filtered power supply and a load. Basically, when the voltage input is higher than the spec it should stop current to the alt's FLD and when it is lower it should allow 3-4A or so through the FLD. Use a 3ohm load to simulate the alt's FLD.

Beware that sometimes it'll test good on the bench, but be bad when it heats up under the hood. They're so cheap that most people just swap in another.
Author:  Orange72 [ Tue Oct 31, 2006 4:48 pm ]
Post subject: 
Autozone will test it for free...just go somewhere else to buy one if yours is bad. :roll:
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