The Stovebolt Site Forums The Shop Area The Electrical Bay Voltage Regulator Question.

Can someone explain to me how the voltage regulator (6 volt) works on my '49 Pickup and also how to verify that the charging system is charging properly other than just by looking at the ammeter in the dash...? Thanks.

You can try putting a voltage meter on the battery with the engine shut off and taking a reading.. Start the engine and see if the voltage jumps a bit..

A shop manual is the best accessory you can have when you own an old truck..Lots of great electrical info in there...

Thanks, that sounds like a really good idea that I hadn't thought of. I am really curious about the contacts on the voltage regulator. It almost seems like that there is slight drain on the battery when the engine is off.

Here's the quick and dirty, but take it with a grain of salt because I kept fighting with mine and finally switched to an alternator.

There are three relays in a generator type voltage regulator. The first one is the cutout, that disconnects the generator and regulator from the battery when the generator isn't spinning fast enough to do its job and keeps the generator from being a motor when the engine is shut off. This should close when you rev the engine. It should be open when the engine is off. It's the one with the big fat contacts on the left. You can test the generator by removing the belt and closing the relay. The generator will spin itself.

The second one is the current regulator, it has a heavy wire coiled around it and opens when the generator is maxed out with current and protects the brushes. If it's closed and its contacts are clean it is fine.

The third one is the one that does all the work, that opens when the voltage across is is strong enough to overcome spring tension and regulates the voltage by cutting the field on the generator. It is usually the one on the right end. It is also the one that tends to get burned and needs cleaning and re-adjustment often.

The adjustment procedure is shown in the manual. I burned mine out after a while because my wiring harness was rotten.

If you think there is a drain from the battery, remove one of the battery terminals and take a voltage reading between the battery terminal and the cable, should be 0v, you can also remove the battery lead with the engine running, if the truck stays runing the gen is ok, you should have between 7.0v and 7.5v across the battery when charging as well

Thanks everyone for the ideas, I'll see what happens...