Tag and disconnect leads, T4, T5, and T6 from terminal block TB202 at the lower left side of rear cabinet
B. Tag and disconnect lines Ti, T2, and T3 from the rear of load circuit breaker CB1 01.
Tie the terminal lug ends of lines Ti to T6 together as follows for proper phase isolation and tag according
(a) Tie lines T4 and Ti together for phase A.
(b) Tie lines T2 and T5 together for phase B.
(c) Tie lines T3 and T6 together for phase C.
Obtain a5 kV dc megohmmeter. Connect megohmmeter leads as shown below, observing proper
megohmmeter lead connections as noted in parentheses (black or red) for each phase set tested. Operate
megohmmeter for 60 seconds for each set under test and monitor resistance reading. After each test,
always short the black megohmmeter lead to ground (where needed) with the cable still connected.
Connect megohmmeter leads as follows:
(a) Phase A (red) to phase B (black)
(b) Phase B (red) to Phase C (black)
(c) Phase C (red) to Phase A (black)
(d) Phase A (red) to ground (black)
(e) Phase B (red) to ground (black)
(f) Phase C (red) to ground (black)
Megohmmeter reading for each set tested should be no less than 5.16 megohms. Any reading lower than 5.16 megohms
is unacceptable. Clean, dry, repair, or replace stator as necessary.
After testing, restore stator leads as follows:
(a) Remove and discard phase tags.
(b) Untie cable terminal lugs.
(c) Restore lines T4, T5, and T6 on terminal block TB202. Remove and discard lead tags.
(d) Restore lines Ti, T2, and T3 on rear of load circuit breaker CB1 01. Remove and discard lead tags.
(e) Reinstall cabinet B rear access panel.
Main Rotor (Main Field).
Perform steps (1) through (3), above.
See Figure 5-1. Remove conduit box cover assembly (6) by removing hexagon head screws (5).
Tag and disconnect the two generator field leads coming out of keyway in the rotor shaft. These leads
connect to each of the two rectifier angles on the rotating rectifier assembly. See detail A, Figure 5-1.
Obtain a 500 V dc megohmmeter. Make sure neither of the two field leads disconnected in step (3),
above, touch any other part. Connect one megohmmeter lead to one field lead and the other
megohmmeter black lead to the aluminum standoff casting (behind insulation plate on exciter rotor) or to
any suitable chassis ground. Operate the megohmmeter for 60 seconds and monitor the resistance
reading. Discharge the main rotor field with grounding stick after performing test.
Resistance reading should be no less than 2 megohms. Clean, dry, repair, or replace the main rotor
assembly as required if reading is lower than 2 megohms.
Reconnect rotor field leads to the rotating rectifier assembly as tagged. Remove and discard tags.
Reinstall the conduit box cover assembly (6, Figure 5-1) using hexagon head screws (5).
Exciter Rotor Assembly (Armature).
Perform steps a(1) through (3), above.
Remove generator conduit box cover assembly (6, Figure 5-1) by removing hexagon head screws (5).