Checking a Voltage Regulator
Moderator
Joined: Jan 2001
Posts: 56,993
Likes: 2,741
From: Virginia
I have never done this, but Mike W says if you get around 11 volts on the field terminal when it's running, then it's working. Although I would think that would be a high rate of charge. It may be less if there is no load on the system. O volts on the field terminal of the alt or reg would definitely be a bad sign.
Post Fiend
Joined: Apr 2002
Posts: 7,157
Likes: 1
From: Central Kali
Hi Guys, the 11 volt figure is when you are not getting any output from the alternator. It is just a quick check to see if the regulator is ok.
On a system that is working you may only see a few volts until you turn on lights, etc. I put a scope on the field terminal one time and it was actually a square wave. As the load increased, it became a constant voltage. A meter wasn't showing the true picture.
I was bored one day and made a test stand with an electric motor to spin the alternator.
The older ones are easy suckers to rebuild for $13 for the kit which has the front bearing, brushes, and the diode assembly.
On a system that is working you may only see a few volts until you turn on lights, etc. I put a scope on the field terminal one time and it was actually a square wave. As the load increased, it became a constant voltage. A meter wasn't showing the true picture.
I was bored one day and made a test stand with an electric motor to spin the alternator.
The older ones are easy suckers to rebuild for $13 for the kit which has the front bearing, brushes, and the diode assembly.
