Installing and Testing Generator Fields

[Tom Wesenberg]

Last weekend I found out that the replacement field coils come with wires long enough to install the coils on the wrong side of the case. I tested a friend's newly rebuilt generator last Saturday and when I polarized it, it spun backwards.

Good fields should draw about 3 1/2 to 4 1/2 amps. You can check the field windings while the generator is on the car by lifting the adjustable brush off the commutator, or placing a piece of paper or cardboard between the brush and commutator. Test with at least a 4 amp charger as pictured and set to 6 volts and the POSITIVE cable on the field ground.

With the output stud facing away from you, as in the picture, the compass needle (NORTH) should face left. It will face left whether you place the compass on the left side of the case, in the center, or on the right side of the case.

Notice that this is the later gnerator with the output stud near the rear, and the field ground is clamped to the case by the insulating washer on the output stud.