Uncovered this on a non running 1953 F100 that had a FE 390 with 12 V generator and 12 volt battery swapped in decades ago. What's this device? Is it some sort of voltage reducer for the 6 volt system? Never seen a device like this.
yes it is, and if all of the resistor wires are still good, it is a great thing to have to those who need one on multiple 6 v accessory/accessories. I've run mine on two old cars as daily drivers . That unit has three different amounts of resistance circuits and the most resisted one is marked for gauges or radio. The other two are stepping down the resistance to run something having more demand in amps, like heater motor, electric wiper motor or etc. I thought they are marked on each resistor circuit to what they are used for. Mine is exact, same looks, but it's made of white ceramic. My first car I used it on was a 57 beetle with 12 volt conversion, but I had the original 6v Stewart Warner gasoline heater under the hood. I used it to be able to run the specially shaped combustion blower motor and whatever else that heater needed. I ran it 5 years as a year round daily. Now it's under the dash of my daily hotrod to be able to use a 1940s Olds heater and separate defroster blower motors. Some people will say that the dash mounted resistor switches for old heaters to make them have high and low, will be fine on 12v. Not true, because that type of resistance speed switch will run crazy hot on 12v, and getting hotter if you run it on low speed. It will eventually burn the terminals or the wires at the terminals. The resistor you and I have, made the dash switch run exactly the same temperature like it once did on a 6 volt car My Olds heater motor, and especially the separate defroster uses a smaller size motor that I couldn't find a 12v modern replacement for. This makes the dash switch work perfectly. I went to swaps and Hershey since 1970 and yours is only the second one I've seen. And yes I drive it as a daily like this pic taken today when I sent out some parts to a Hamber at the post office. It was windy and 24 degrees .
Thanks for the info. I suspect this one is/was white ceramic but it's got decades of dirt and paint overspray on it. I'll be removing it and cleaning it to take a closer look. That said, I'll be going full 12 V with aftermarket instruments on the build and probably won't be using it.
That looks like it actually regulates to the desired voltage. This means it will give you the correct voltage even when the load changes, the resistors can not do this and as a result voltage will vary when the load changes. If you pick the right resistance for, say, a number of instrument light bulbs and one blows the load goes down, voltage goes up, and the remaining lamps soon follows - for every one that pops the rest get even higher voltage and shorter time until the next blows. If the radio gets correct voltage at max volume it may get too high at low volume. And so on. Resistors are very simple. They are acceptable voltage droppers for a steady, known load. For a varying load they are somewhere between not great and absolutely horrible, depending on the situation. In many cases an electronic regulator can do a much better job. (Yes, yes, I know, it's not traditional. Are 12V conversions traditional? Are brake pads without asbestos?)
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