Third Brush Thermostat and Resistor

[Wayne Womble 12210]

Would anyone know the resistance value of the resistor unit on Delco generators. Or maybe where any could be found?  The resistor is wire wound and mounts on the third brush thermostat? Specifically for 31-33 Cadillac/Lasalle, but used on other GM products.

[Doug Houston]

I think that your only hope will be to find a known good resistor and measure it. The resistor values were likely to vary each year, so youd need to get hold of the exact one. Those values are never given anywhere, so your own private sleuthing is necessary. I dont know the wattage rating of those resistors, but it could be calculated, Im sure.

[wombvette]

It looks like it is a common occurence for this part to fail. Out of the three that I have here, two are bad. I have yet to remove the good one in my 31 to measure it, but from measureing the two burned out pieces of the one that I have out, it looks like about 1 ohm. That makes sense. Dykes Auto Encylopedia says that three different values are available but Cadillac only list one in the parts book. The only problem is that it also acts as a fuse to guard against burning the generator up. So the resistance would probably vary considerably with heat and amperage. This makes things difficult to figure. It acts as a current limiting resistor and a fusable link. I will have to experiment.  

[Wayne Womble 12210]

Sorry for the alias in the previous post. Hit the wrong button.

[Rhino 21150]

http://www.surplussales.com/Resistors/WireWound/WW0015-1.html TARGET=_blank>http://www.surplussales.com/Resistors/WireWound/WW0015-1.html
IF the resistor is one ohm as Doug said, use the 12 watt resistor on this page. It will burn out at about 4 amps, acting like a fuse. Buy a bunch at $2 each and if they keep popping, you have the wrong value! Then repost and maybe someone can measure a good one!

[Wayne Womble]

Thanks, Thats an interesting site.  The resistance wire is a possibility.