Disassembly Procedure
- Remove generator. Mark a match line that cannot easily be removed on end frame to make assembly easier. Pry off plastic cover to expose stator connections. (Scheme 7) Remove stator connections from rectifier bridge terminals by cutting wires. (Scheme 8) Remove generator through-bolts. NOTE: If stator connections are not welded, melt lead. Avoid excessive heating, as it can damage diodes in rectifier bridge. NOTE: The fastening torque of drive end bearing nut is 81 N.m (60 ft. lbs.) and may not normally be unfastened using hand strength.
- Remove drive end bearing nut. For vehicles with an internal fan. remove pulley and collars. Test rotor for an open circuit by using ohmmeter with drive end frame assembled. (Scheme 9) The reading should be sufficiently high, or rotor must be replaced. Test rotor for open and short circuits. The reading should be 1.7 to 2.3 ohms, or rotor should be replaced. Remove drive end frame from shaft.
- For vehicles with an internal generator fan, remove drive end frame and fan. Remove rotor assembly. (Scheme 10) Remove stator. (Scheme 11) Test stator for an open circuit using ohmmeter. Pry off baffle. Remove rectifier/regulator/brush holder assembly screws. Remove brush holder assembly and regulator, cutting terminal between regulator and rectifier bridge. (Scheme 12) NOTE: If brush can be reused, reassemble brush to holder with retaining pin, after cleaning brush with a soft, clean cloth.
- Test rectifier bridge by connecting ohmmeter terminals to bridge and heat sink. (Scheme 13) Retest by connecting ohmmeter terminals in reverse order. (Scheme 14) Replace rectifier bridge if each reading is same. Test remaining two diodes after above procedure. Test diodes by connecting ohmmeter terminals to bridge terminal and baste plate. If reading is same, rectifier bridge should be replaced. Remove ring in slip ring end frame. NOTE: Some kinds of digital ohmmeters are not suited for testing bridge diode. In this case, consult manufacturer regarding test capacity.
Scheme 7
Scheme 8
Scheme 9
Scheme 10
Assembly procedure
- Install new ring in slip ring end frame. Push new bearing outer race into bottom of end frame casting. Weld brush holder terminal to regulator terminal, if removed. Fix brush holder with retainer pin, and weld regulator/brush holder assembly terminal to rectifier terminal. Apply silicone grease between bridge and end frame for radiation purposes. NOTE: Take care to protect diode in rectifier bridge from excessive heat while welding.
- Fasten screws holding rectifier regulator/brush holder assembly to end frame. Punch new baffle with pin into brush. Install stator. Weld connectors of rectifier bridge. Install outside cover. Position rotor assembly shaft with drive end frame in slip ring end assembly until gap between outer race and end frame casting is 1.9 mm (.075"). Install generator through-bolts.
- Tighten generator through-bolts to 10 N.m (89 INCH Lbs.). Position fan, collars, and pulley on rotor shaft and secure with nut. Tighten generator drive end bearing nut to 81 N.m (60 ft. lbs.). Install generator.
