VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt Which generator and why

I have two visually identical short frame generators, (52 or 53}. One starts charging under 2000 generator rpm on my test bench and the other needs over 2900. The regulator is switched from one to the other without change. I think there must be a construction difference but what is it?

There were several versions of the short generators and each one used a different regulator. The speed of the generator for output was different for each

You need to have the generator noumber and then look up the correct regulator for that generator.

Gene, what are the results if one doesn't do as you have suggested? I notice that many parts sources offer only one regulator for certain stretches of years. I have two generators that have been modified, one has been converted over to 12 volt and the other being 12 volt I had the front pulley swapped to the wide belt so I can maintain original look. What are the hazards of running an incorrect regulator as long as the voltage is correct?

The regulator controls both the amperage and voltage. If the regulator will allow a greater amperage output than the generator is capable of producing, the generator could overheat. This could either burn out the field coils or let the armature get so hot that it "de-solders' itself.

Am I right to assume that if one doesn't exceed the amperage that the generator puts out it is not likely to be harmed by running an incorrect regulator as long as the voltages are the same? I ask because I have two vehicles that I converted to 12 volts and do not know which regulators I installed. I guess I can pull numbers, but if it isn't necessary, then I won't lose any sleep over it. I am not running anything but lights at the present time, but who knows later. I may run heater/ vent fan and radio at a later date.

I am guessing that you meant the amperage that the generator is rated for as it will try to put out whatever the regulator is set for. My thoughts are that the regulator should allow the generator to perform at max for a short time and most of the time just to maintain the battery and operate the electrical systems that the vehicle was designed with. I don't think it would be good to run the generator at max for long periods as that would just lead to a shortened life.

The current regulator (inside the voltage regulator assembly) is there to put an absolute upper limit on how much current can be drawn from the generator. Usually it does nothing. The voltage regulator (also inside the voltage regulator assembly) sets the voltage the system charges at, and that takes care of charging all by itself most of the time.

The trouble is a generator, unlike an alternator, will happily charge way over it's rating if allowed to. This would not usually occur. If the battery were half dead (half dead batteries draw a lot of charging current), and the lights, or accessories were running, and the current drawn added up to something that exceeded the generator's rating, the generator could suddenly burn up (literally).

The car might do fine for years, and then on that one bad day, during a perfect storm of conditions, the generator might melt, smoke, and throw solder all over the place.

The current limit needs to be checked and set according to the shop manual. If the regulator is the correct one, it should have been right when it left Delco, but a lot of time has passed. It might not be right anymore.

If a person were trying to use a different than recommended regulator, the current must absolutely be set. For instance if the generator were a 30 amp unit, and the current regulator was set to 40 or 45 amps, you might never know anything was wrong until you ran the battery low (due to vapor lock or something), then two blocks down the road the smoke starts pouring out from under the hood.

I appreciate all the replies. Of interest might be Delco-Remy service bulletin 1R-116 which I found and downloaded from the internet. It has a lot of regulator theory.

So in essence, if I use a 30 amp regulator it should not matter what the generator is rated for. As stated earlier it would pull a very light load as it is configured now. Since one generator was converted from 6 to 12 volts I have no way to know with any certainty what it is rated for. So in essence, am i safe to play it cautiously and go with the lesser rated regulator? the vehicles in question are '46 and '50 Chevys in stock configuration except 12 volt conversion.

Assuming everything is Chevrolet, and Delco, then having the current set too low just means that is all the current you get, so if the generator is capable of 40 amps without damage, and the regulator is set at 30, you just get 30 amps maximum, and nothing burns up.

If other car makes are in the mix (even if all Delco), then there is the possible issue of "A circuit" vs "B circuit". This has to do with whether the regulator sends 6v to the field to make it charge, or grounds the field to make it charge. You cannot mix the two. It won't work.

If there is a 12 volt conversion in the mix, I have no idea. Maximum current capacity is more or less independent of voltage, so if the armature was still the same one, it could be capable of the same current (amps) at 12 volts as it was it 6 volts. If the armature was changed all bets are off. Only the guy who built the generator would know exactly what he did.

I still vote for using the right parts whenever possible, and setting the current regulator to match the generator's capability.

Thanks guys, I have no idea what the converted generator is rated at and will have to check numbers on the other. Since I am not powering anything significant, I will not lose any sleep over a 30A regulator. I do concur that when one can, they should use the appropriate parts. I may need to do the same for my '46 coupe even though both generators are 1961 12 volt and the regulator should be the same vintage. I will run the numbers. Too, the '46 is not powering anything but the stock basics except for the 12 volt conversion.