S/G Questions

[702854boy 528]

Is there supposed to be continuity between the a terminal and the housing? Is the supposed to be continuity between all of the commutator sections? Should there be continuity between all of the winding metal pieces?

[953 nut 64,336]

One of these manuals should have all the information you need.

https://www.wheelhorseforum.com/search/?q=delco&quick=1&type=downloads_file

[ri702bill 11,410]

Or, this one... it is a large file.

 

DELCO-REMY_SERVICE_BULLETIN.pdf

[Handy Don 16,019]

Learning the ins and outs of S/Gs, including how the electro/mechanical (i.e. NOT electronic) voltage regulators work, gives one a deep appreciation for clever engineering. 

[702854boy 528]

I don't get it. We have done pretty much all of the tests, we have check for grounds and we have checked for shorts but for some reason the darn thing still won't charge. It also has new brushes and a clean commutator. It seems no matter what we do, it still won't charge, it'll start the tractor all day though until the battery is too weak. And when it's running I disconnected the regulator to see if that was the problem and I was still only seeing 12.5 volts at the battery which was probably the battery voltage and not a charge.

[wallfish 19,393]

Instead of checking the voltage at the battery with the regulator disconnected, check it at the regulator

Leave the cap off the regulator, are the points closing after it starts?

[702854boy 528]

The one point I don't think was closing but that's the point on the right side of the tractor and with the regulator connected it shows the same volts as disconnected which makes me thing that the s/g isn't putting out instead of the regulator being out of whack. 

[Handy Don 16,019]

31 minutes ago, 702854boy said:

The one point I don't think was closing but that's the point on the right side of the tractor and with the regulator connected it shows the same volts as disconnected which makes me thing that the s/g isn't putting out instead of the regulator being out of whack. 

Not disagreeing with you, but what is the history here?

Regulators are rugged but not invincible. I’d start with the regulator diagnostics in the documents above. One thing I look for is the “left” relay must close to switch from “starter” mode to “generator” mode (this one is not adjustable even on adjustable regulators). If it doesn’t close, then no charging--could be no juice from generator OR could be a regulator fault. 

Edited 17 hours ago by Handy Don

[pfrederi 19,971]

First simple question is it the Regulator or the Generator itself that is the issue.  Engine running at at least half throttle what is voltage at the battery....  13.5 or better is ok  12.6 no good step 2

 

Run a jumper wire from the "F" terminal on the generator to the "-" on the battery.  If voltage goes up from 12.6 maybe to 14 then your issue is the regulator if it stays at 12.6 then probably one of the genny field coils is bad ...but more testing is appropriate.

[702854boy 528]

5 hours ago, pfrederi said:

If voltage goes up from 12.6 maybe to 14 then your issue is the regulator if it stays at 12.6 then probably one of the genny field coils is bad ...but more testing is appropriate.

When we did this test before the voltage didn't go up or down, it stayed the same, but all of the other tests we have done such as checking for grounds and open circuits has checked out all right.

 

6 hours ago, Handy Don said:

Not disagreeing with you, but what is the history here?

The tractor was parked in the early 2000's and we brought it back out in '22 and it was charging fine until last winter and then no matter what we do we can't figure it out.

[pfrederi 19,971]

Since you did brushes and such likely failure is the Charging Field coil.