Alternator Repair

To repair the alternator, observe the following procedure.

Disassembly

Note or mark the front to rear housing relationship, this is the "clock" Position. You must know it for re-assembly. Then remove the 3 thru-bolts and separate the drive end frame assembly from the slip ring end frame assembly. The stator should remain in the rear (D.E.) housing. To remove the drive end frame from the rotor, place the rotor in a vise, using wood blocks or brass jaws so not to damage the rotor then tighten only enough to permit removal of the shaft nut, or hold rotor with hex wrench in end of shaft when removing nut. To disassemble slip ring end frame (Figure 4) proceed as follows:

1. Punch out cover rivets, or pins, (figure 4), and discard cover.
2. To separate stator from end frame assembly. cut off or unsolder the leads at rectifier bridge terminals.
3. Remove stator.
4. Punch out baffle pins, Figure 4, remove baffle.
5. Carefully note the position and internal connections so reassembly can be made correctly as shown in Figure 5.
6. Detach fasteners, lift brush holder, regulator. and rectifier bridge from end frame.
7. Unsolder or un-crimp, as needed, the connector to disconnect regulator from rectifier bridge, and from brush holder.

Rotor, Field Winding (Stator) Checks

Connect test lamp or ohmmeter from one slip ring to rotor. If lamp lights, or if reading is low, the rotor winding is grounded (Figure 6). To check for opens, connect the test lamp or ohmmeter to each slip ring. If the lamp fails to light, or if the ohmmeter reading is high (infinite), the winding is open, replace rotor. If the rotor is not defective, but the alternator fails to supply rated output. the defect is in the rectifier bridge. stator, or regulator.

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