I am not experienced with a generator operation, but I understand that they charge very little at idle. My 60 has worked fine since I have owned it, but just doing some voltage measurements I noticed that at idle my generator reads about 0.55 volts on the field terminal and battery voltage at the battery terminal. If I raise the rpm to 2K, it goes over 25v, but reading at the battery terminals, I still get the expected 13.4 volts at that rpm. For someone with generator experience, is it unusual to get such a high voltage on the generator? It seems the regulator is handling it, but just seems odd.

 

First, you speak of the generator but next you speak of the field terminal and battery terminal --- there is no battery terminal on the generator but rather field and armature. Inside the generator one side of the armature is directly grounded through a brush and the brush on the opposite of the commutator is connected to the A)rmature terminal. That terminal is also connected internally to one end of the field coils and the other end of the field coils is connected to the F)ield terminal. This means that if you measure from A)rmature to ground you see the generators output voltage and to get full output the F)ield terminal must be grounded. Normally this grounding takes place through a set of points in the voltage regulator that open and close rapidly.

The regulator has B)at, A)rm, and F)ld terminals so if you are measuring between A)rm and Ground it would be very unusual to see voltages more than 1 or 2 volts above battery. You should measure essentially the same voltage across B)at and Ground as you do across the battery itself within a fraction of a volt. If you measure anything more, it means there is high resistance between the B)at terminal and the battery connection.

The Field and Armature terminals on both the generator and regulator are directly connected so you should measure the same at either end. The first thing I would do is make sure that both the generator and regulator are well grounded and if you still see a large difference between B)at to ground and A)rm to ground that almost certainly means that the cutoff relay contacts are burned, dirty, or misadjusted. It could also mean that the cutout relay coil is weak.

 

I don't understand the explanation. The battery terminal I mentioned was the terminal on the battery, not the generator. On the battery I read 13.4 at 2000 rpm. All I need to know is how much voltage should you measure on the field terminal on the generator at rpm's above idle. I got 25 volts on the FIELD terminal on the generator and 13.4 volts on the + terminal of the battery. I have had no problem with either the battery or the generator, I just want to know why the field reads so high at rpm's.

 

Voltage between an ungrounded F terminal and chassis ground will have your meter acting as the ground path and with an open circuit you read full potential from the armature via the field coils.

Dan

 

I don't understand how you are getting 25 volts. The field terminal should be only slightly above ground most of the time. I'm trying to imagine what the voltage might be spiking to just as the regulator points open but your meter would have to be set to capture peak voltage and that peak would be very brief. The field terminal should never rise above 3 or 4 volts and that's a stretch. When you measure 25 volts where are the meter terminals connected?

 

I assume he is between F on the gen and ground.

Dan

 

Thanks Dan. It would never have occurred to me to make a measurement on an open field. My brain ain't wired that way.

 

I measured it because I was curious, and wanted to know if it was normal to read over 25 V connected from the field on the positive meter lead and the negative meter lead on ground with idle over 2000 RPMs. At idle that same point reads .55 V and as I said, I was curious.

 

I would think at 13.4v generator output, the Field would not be 25 v. Maybe 2.5v or 25 mV.

Field at 0v(ground) would output around 18-20v. This would be field coils at maximum operating condition, i.e. full field.

You may want to do the following test in Fig 9 below.

https://chevy.oldcarmanualproject.co...8dr521006.html

 

Thanks guys, it's not worth all this. I was just checking some voltages and randomly measured the field, it read .55 at idle so I revved it up and it read over 25v. I have no charging problem, no battery problem. Same generator and regulator from factory and same battery for 6 years. Maybe someone with c1 generator at some point could read on their field coil and pm me what you see. Just don't know how it's supposed to read or if it matters. Thanks again.