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Can I check the voltage output of my generator while it is still in the car? Seems simple enough but fooling around with my volt meter has proven nothing. Any suggestions? 1930 chev. coupe. Thanks. Jim

Sure! Since you have a 1930 Chevy, your generator should be a model 943-J. Using your volt meter, connect the negative to the generator case and the positive to the wire coming out of the generator that is connected to the generator post of the cut-out. You can also test the voltage at your battery as well.

Dog, you are a true gem. Thanks for the quick reply. Tomorrow i will sally forth, volt meter in one hand and a fine malted beverage in the other and test away. I'll let you know what happens. Jim

Bow Wow!!

Bow Wow indeed.
The Dog is a car nuts friend AND takes lots of interesting pictures too.

You should do your voltage checks with an analog (needle) voltmeter, at least at first. I have seen several digital voltmeters confused by the noisey voltage coming out of generators. If you are not sure of the accuracy of the analog meter, compare it to a digital meter on the battery, with the engine off.

To do a good test, you should be within a tenth of a volt.

Wilson is correct!

I have used both an analog volt meter and a digital volt meter. For the "in-depth" readings I use a Simpson Model 360 digital meter and that baby is the "cat's meow" for checking voltage on a charging system. So far I have had no problems with it when testing generator output.

dog & et al, so today, after work i fired up dear old babzy (30 coupe) and with my analog volt meter i put black to the generator body and red to the positive terminal and got no reading. then i put red to red at the voltage reg. and black to black there too and got 7 volts. then i put meter red to the hot terminal on the starter and the black to ground and got 7 volts. all this suggests an out put from the generator but why no reading from the generator itself? jim

Is the generator turning fast enough to generate? My 33 with the same generator does not charge at my normal idle speed.

I don't understand your red to red and black to black comment, so I'm not sure where you are putting the leads. You have no regulator, only a cut out on the original generator.

geo., re:red to red...red lead from volt meter to the red lead to the regulator and black from the volt meter to the black lead at the reg. = 7v. and no, i didn't have the engine up at high idle as i did this. i'll do that. jim

dblclh: Again, as George33Eagle mentioned, you do not have a regulator! You should have a cut-out on top of the generator instead. As also mentioned in a previous post, your generator should be a model 943-J, which is a three brush generator, with the third brush adjustable for the output. With this system no voltage regulator was used......only a cut-out.

dog, then what is the square black thing on the fire wall with 3 wires going to it? sure looks like the voltage regulators i use to bang on(i broke a catsup bottle on one in my 53 chev pu truck in 1972). so maybe the generator isn't original or someone re fitted the coupe like this, but that box with the 3 coils has always been called a voltage regulator for my 60 years. so, given this twist, how ought i for now check the voltage out put of my hybred system? a little compassion now lads. jim

You can get help here, but if you ask for help on a 1930 generator and have something else you are likely to get the wrong answer. It sounds as though your car has a 1940? to 1954 generator and voltage regulator. JYD is familiar with that era, as well as earlier, but I am not.

dblclh: Yes, that little black box with the three terminals on it is indeed a voltage regulator. However, in your first posting you stated that you had a 1930 coupe and you asked how to check the voltage output of your generator. You were given the model number of the 1930 generator (943-J) and the instructions were given on how to test the stock generator output (which has a cut-out and not a regulator) with a volt meter. You never acknowledged the generator model number posted nor did you give us the specific information needed that your generating system has been changed to a voltage regulator system. Therefore, the answer you received was for the stock generating system for 1930.

Since your car has been changed to a non-stock charging system with a voltage regulator the hookup for your volt meter is different. To check the output of the generator at the voltage regulator, place the red probe of your volt meter on the "B" terminal of the voltage regulator. Place the black probe of your volt meter to a good ground. Increase your engine speed and take a reading on the volt meter. That is your output.

Good luck with your test!

dog et al, i tried the above suggestion and got 7v. the generator is labled "united parts U P remanufactured" 9 65 gd 18. seems to work though so i think i have charged my battery one too many times over 3 years time. only you folks here know my shame of running with a non '30 generator so as long as it works i will wash, wax and be ready for the good weather. thanks. jim

Yep, you have a replacement generator with a voltage regulator instead of the stock 943-J generator with the cut-out mounted on top.

Too bad - that modification probably voided your factory warranty!

it also fried my multimeter while dinking with the hybred voltage regulator. nothing's free. j