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| | | | Joined: May 2008 Posts: 142 Wrench Fetcher | | Wrench Fetcher Joined: May 2008 Posts: 142 | Hi,
I am working on a 1946 Chevrolet Utility, 12 volt system. Upon teardown of the front clip to replace the harmonic balancer and water pump, I noticed the generator end frame is cracked and the flange is damaged. I have a few generators sitting on the shelf, but do not know if they are 6 or 12 volts.
Is there a visual way of determining a 6 volt or 12 volt generator? If not visual, can I use a volt meter to test for 6 or 12 volt?
Thanks,
Dale
| | | | | Joined: Aug 2000 Posts: 346 Shop Shark | | Shop Shark Joined: Aug 2000 Posts: 346 | Check the ID tag riveted to the generator.
Black tag = 6v
Red tag = 12v
'38 Chevy 1-1/2 ton
'49 Chevy 1/2 ton
'54 Chevy 6400 2 ton
'55.2 GMC 3/4 ton
'56 GMC 1-ton
No Room Left in Shop
| | | | | Joined: May 2008 Posts: 142 Wrench Fetcher | | Wrench Fetcher Joined: May 2008 Posts: 142 | Thanks OlBlue,
The generator on the truck is missing the ID tag, and has 12V stamped on it. On the other ones, I am not sure if the tags are still there. What I am interested in is a bench test?
Or can I install one off the shelf, mount it on the engine with no wires attached and get a voltage reading? | | | | | Joined: Mar 2002 Posts: 9,115 'Bolter | | 'Bolter Joined: Mar 2002 Posts: 9,115 | I ran mine on the bench with an electric motor and belt. With the field grounded and no load it produced 20 volts. That was a six volt. | | | | | Joined: May 2008 Posts: 142 Wrench Fetcher | | Wrench Fetcher Joined: May 2008 Posts: 142 | Great, do you know what the RPM of the motor was? If I use the engine as a test stand, will the voltage output increase/decrease with the engine running at various RPM? | | | | | Joined: Feb 2004 Posts: 29,777 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,777 | Try measuring the field coil resistance with an ohmmeter, from the "F" terminal to the insulated brush holder. Use your known 12V field coils as a reference. If there's a noticeably lower resistance, you've got a 6 volt field coil set. I don't know of a quick way to identify a 6 volt armature.
Jerry
Edit: With no wires connected and the armature turning, a polarized generator will produce about 2 volts at the armature terminal, but there's no way to predict where the voltage will go with the field grounded and the armature terminal open-circuited. It would have to be connected to a battery so it can generate some current. Open-circuit voltage can go above 50 volts, and it just keeps increasing as speed goes up.
Last edited by Hotrod Lincoln; 02/19/2010 5:47 PM.
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