Technical Stoopid electrical question

I put a 12V generator on a 346 caddy motor. Hooked it up and I'm only getting 10V on the voltage gauge. I had the generator tested prior to installing it and it's kosher.
I reconnected the gen wires as they were but I have a feeling the wires may be crossed as the old generator never charged the system either.
So would swapping the wires on the generator hurt anything?
Feel I have to ask before i before I do it seeings how I know jack shit about electrical stuff.

 

what do you have for a voltage regulator?

 

Looks like a GM one

 

The car starts and runs good. Just no charge

 

Check the voltage at the battery with the car running, using a volt meter. Maybe the gauge in the car is inaccurate?

 

Do you have any idea if it's for a 6v or 12v system?

 

You may have to polarize the generator. Use the exact procedure as described in the manual, not what your BIL tells ya. GM is different than Ford.

DON'T swap wires around willy nilly, you may let the smoke out. Process of elimination. Find a schematic and trace out the wires. If you get two out of the three figured, that will work.

Generators and regulators need a little attention now and then. I don't know jack schitt about electricity either but I can clean ground points with the best of 'em. Probably Most electrical problems and weirdness are caused by bad grounds or corroded connections. Always use fresh heavy duty cables, not that drug store shit.

 

12 volt

 

Can you trace the wires, to make sure they're connected properly? should be a Field and an Armature, eh?

 

check the voltage across the battery terminals when running, and compare these to the voltage on your voltage gauge.

if there is a difference it is probably a case that the earth connection on your voltage gauge isn't good.

 

Did you speed the engine up to about 1500 to 1800 or so rpm so the generator would put out it's full output? They normally won't put out much of a charge at an idle.

 

Make sure to polarize the generator according to the manual. The field wire goes to the F terminal and the armature or stater goes to the A or S terminal. The other wire on the regulator goes to the battery through the amp gauge if you have one. Bring the RPM up to 1500 when testing. Some regulaters are adjustable.

 

Short answer, no. It has to be wired correctly.

Firstly, I believe 346's were from '41 to '48, since I think Caddy went 12v in '53, the stock genny would be a 6v. You might not even be using this motor in a Cad at all, let alone a 41-46.

This all means nothing if you have upgraded to a 12v system, so let's assume you have. Then if you are using a 12v generator, the amperage of the genny has to match the amperage of the voltage regulator, for example: a 1960 Caddy generator/regulator combo would be 35 amp W/O A/C, 45 amp W/ A/C. You should find a wiring diagram that goes with whatever the original application is of the generator you are using. If you miswire the genny and the regulator you may fry both of them. I have done this and fried several regulators and a genny before I understood it.

As an example, if you are using the 12v generator/regulator from a 1960 Cadillac here is a close up of the diagram that relates to the genny
The "field" marked FLD on reg can only be wired to the F terminal on the genny, the "GEN" to the "A" terminal on the genny, and the "BAT" to the positive terminal of the battery, ground to body. If you aren't using a Cad genny, verify it's the same with it's manual.

These generators are only going to produce 10 or 11 volts at idle, not charging the battery until you wind the engine up and it should be 13.5 to 14.5, then it's actually charging the battery. With a fully charged battery it will still read 12v, but the genny is only putting out 10 or so. The pully on a genny for an A/C equipped car is smaller, making it spin faster and producing more amperage to accommodate the extra draw. So you can run more stuff and it will still be pumping out 14v.

If you use the wrong regulator, it could cut off to early or too late, not allow enough/too much voltage through and/or overheating generator. Newer regulators are not adjustable, older ones can be. A 35amp genny should only be used with a 35 amp regulator, and so on. Other makes might have positive grounds, so I am not sure if regulators are interchangeable.

I probably am wrong about a bunch of things, and I'm sure someone will point that out, but this is some good reading:
http://www.stinsonclub.org/PublicTech/YahooGroup/DC generator theory.pdf

Let us know how it goes, it may help others solve a problem or two

(In the time it took me to write this blather, 14 other people posted and OP answered some questions, but I'm too lazy to edit so forgive my redundancies)

 

Also, your Batt may just have a full charge in it. Turn on your lights while running at above 1K rpm and watch the gauge. Unlike an Alt charging system where your running on charge output with a Gen your running off the Batt. When the Batt is full up the Gen kicks off line till the Batt volts drops then the Gen re charges the Batt up. That's when you see a Volt increase on gauge.
The Wizzard

 

Great comments on generators . To those who have never dealt with one. I grew up using generators good refresher.