BOOK0795-F
27
9. Line and motor arma-
ture current excessive
Motor overloaded
Check shunt field current.
a
Low shunt field
current causes excessive armature current. If
field current is adequate, check for a mechani-
cal overload. If the unloaded motor shaft does
not rotate freely, check motor bearings. Also
check for a shorted motor armature. Motor
overload can also be caused by incorrect gear
ratio. Correct accordingly.
10. Shunt field current
a
too low
Open shunt field winding or wiring to
the motor shunt field
Check the motor shunt field and associated
circuitry for a loose connection or a broken
wire. Repair accordingly.
Shunt field connected for incorrect
voltage
Check motor rating and refer to Table 14,
page 37.
Shunt Field Bridge BR1 failure Replace BR1 or the control board.
11. Shunt field current
a
too high
Shunt field connected for incorrect
voltage
Check motor rating and refer to Table 14,
page 37.
Shunt field windings shorted
Measure the shunt field resistance and com-
pare with the motor rating. Repair or replace
the motor.
12. Motor thermal guard
tripped (if used)
Ventilation insufficient
Remove dirt, dust, and debris from the motor
intake and exhaust screens.
Excessive motor load at low speed Reduce the load or increase the speed.
Line and motor armature current
excessive
See Indication 9.
Motor overheating from friction Check for misalignment. Realign the motor.
Shorted motor windings or faulty bear-
ings
Repair or replace the motor.
a. Does not apply to permanent-magnet motors.
b. Does not apply to shunt-wound motors.
TABLE 6. TROUBLESHOOTING
INDICATION POSSIBLE CAUSE CORRECTIVE ACTION
Contd on next page
To Next Page
Loading...