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Voltage regulator for D40 Rugby

I have been running my 29 Rugby on 12 volts for many years using the original 6 volt generator. Probably not technically the best thing to do however it seems to work fine and not cooking the battery. One thing is that the third brush needs to be backed almost right off and then the current charge is 5 amps. Need to push it up a little if running the lights.

I did some measurements a while ago and found the voltage without the lights on was creeping up to 15 odd volts which is a bit high for my liking even though it appears to have ill effect on the battery. I have thought about building a voltage regulator for the generator to keep things a little under control and prevent the need to alter the third brush when using the lights.

Has anybody tried this when running the original generator on a 12 volt system.


Where Are You From? Australia

Do You own a car built by Durant? 1929 Rugby

Re: Voltage regulator for D40 Rugby

Interesting. Other than the battery, what other components are rated at 12V?
Sounds like the generator is running full tilt and the battery is only getting a partial charge. I've never heard of anyone running such a setup because it defies all good electrical practice. However, a generator is capable of pumping out in excess of 110 volts unregulated. 8 volt batteries have been run on 6 volt systems in the past, so why not 12 or more. Perhaps only the generator would be the deciding factor. If so, this would go to demonstrate the stout design characteristics of these AutoLite products.
Perhaps someone with a deeper understanding of electrical dynamics can shed some light on this.

Where Are You From? Texarkana, TX

Do You own a car built by Durant? Several

Re: Voltage regulator for D40 Rugby

Been a while getting back to this message. I changed the coil to a 12 volt unit and all lamps to 12 volts. The starter was left as a 6 volt unit as well as the generator. The horn runs fairly fast on 12 volts but really needs a 1.2 ohm 50 watt to drop the voltage back to around 6 volts. It is on the list of things to do. I know what I have done is not technically correct but I have been running the car like this for several years now without any problems and never have to add water to the battery.

The specs on the original generator quote a maximum of 16 amps at 8 volts. This is 128 watts. Running my generator on the 12 volt system I can, with the 3rd brush set at maximum, obtain 12+ amps which is 168 watts. However I never run the charge at more than 4 amps without lights. This is the minimum I can get from it as the 3rd brush goes to earth when it is right back and the charge stops.

Thinking about it I should place a resistor in series with the 3rd brush to drop the field coil voltage a little. This will allow better setting of the 3rd brush. I am going to experiment with a conventional 3 terminal regulator then maybe experiment with an electronic version if the first one goes well.

The total load, in amps, on the 12 volt system is about half that of a 6 volt system so the wattage is still well within the original specs of the generator.

Sorry for the ramble.

Where Are You From? Qld Australia

Do You own a car built by Durant? Rugby D40


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