OK, good diagnosis so far! Watch the ammeter when the field is grounded to see if it deflects toward the charge side. It should be going virtually full-scale to the + direction with the field grounded and the engine at fast idle. You need to increase the spring tension on both the current regulator points (middle coil behind the A terminal), and the voltage regulator, (the coil behind the "F" terminal on the regulator. Don't overdo it on either one, just slightly increase the tension on both sets of spring-closed points. The current regulator prevents the generator from overloading itself when charging against a very low battery, and it shouldn't allow more than 35 amps of current flow. Some of the early generators were rated at 25 amps. The voltage regulator must be able to raise the charge voltage high enough to force a charge into the battery, and yours is obviously adjusted too low. Normal voltage against a low battery should be at least 12.5, so increase the spring tension on the VR points first. Be sure the cutout relay points are clean, as oxidation there will limit charge current and give the voltage regulator a false indication of the battery's state of charge. Do you have an ammeter to monitor the charge current (not voltage) other than the one on the dash? It's VERY difficult to get a good regulator adjustment without being able to monitor both current and voltage.
The fact that the armature voltage goes up with the field grounded eliminates the generator as the source of the problem. If you're not able to adjust the regulator points and make the system charge, just replace the regulator assembly. There is no need to repair or replace a generator with those output numbers.
Jerry
Last edited by Hotrod Lincoln; 03/29/2011 6:28 PM.
