Generator/ regulator issues

[N6159P]

[Dale Vandever]

Check to be sure that you don't have the old original aluminum wiring and then check your ground cable connection to the airframe.

Dale

[kflyer]

I may have a regulator in the hangar off my '59.

[AlanBreen]

Generators are generally reliable and providing the brushes are in good condition and there is not any obvious internal damage should work OK.

As Dale suggests check check the wiring and earths.

I would suspect the regulator, it's a while since I have played with the old style regulators but any automotive electrical technician shoud be able to check it out.

If you need a new regulator I would recommend Zeftronics who produce an excellent product.

[15384]

59P I put the Zeftronics regulators on my twin and they have worked great.

John

[N6159P]

Before spending the additional money and to troubleshoot the system, I changed the regulator with a cross over automotive type to see if the output would be any different. The output of the generator at 2000 RPMs is only 12.8 volts. At 1500 RPMs the output is only 12.4 volts. We are measuring this at the battery postive terminal and a ground strap. Is this the correct place to measure the voltage? We have been told to ground the Field post on the generator for a couple of second to see if the voltage measurement would climb uncontrolled into the 18 volt range. Is the a correct diagnositic test for the generator to see if the output is adquate? The orginal aluminun wiring is still on the plane, could this be causing some of the issues?

[AlanBreen]

Those voltages seem slightly on the low side. I would normally check the voltage at the battery like you have or at the regulator.

I take it from your comments that these voltages were the same with both regulators. To me this would rule out the problem being the regulator.

You can check the condition of the wiring and the connections to some degree by comparing the voltage at the generator and the battery. There should be little or no difference between the two. If there is, go looking for bad connections.

The aluminium cables are usually more of an issue with starting and I wouldn't normally suspect them in this case.

Grounding the field terminal is a good quick way to check out the generator. After all this is all the regulator is doing to a greater or lesser extent. Just don't do it for too long as a prolonged high voltage will not be good for the battery. A few seconds won't matter, just make sure that there is no voltage sensitive equipment turned on when you do it.

When the brushes were replaced did you have a good look at the internals of the generator? I have seen the winding leads come away from the comutator and require resoldering back on. Also did you check the bearings, a loose or worn bearing could cause the brushes to bounce on the comutator, this will cause low output.