Fincor 2602 - Page 30

BOOK0795-F
25
3. Controller fuse blows
when a Start command is
initiated
One or more SCR‘s or Diode D1
shorted
Replace shorted devices or the control board.
Motor shorted or grounded Repair or replace the motor.
Control board failure causing SCR’s to
turn-on fully
Replace the control board.
4. Controller fuse blows
while the motor is run-
ning
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.
Loose or corroded connection. Wiring
faulty, incorrect, or grounded
Check all terminals, connections, and wiring
between the line, controller, and motor.
Motor shorted or grounded Repair or replace the motor.
One or more SCR‘s or Diode D1
breaking down (shorting intermit-
tently)
Replace shorted devices or the control board.
Control board failure causing SCR
false firing or misfiring
Replace the control board.
5. Minimum speed exces-
sive
Minimum speed not adjusted correctly
Turn the MIN SPD potentiometer counter-
clockwise.
Control board failure Replace the control board.
6. Maximum speed
excessive
Maximum speed set too high
Turn the MAX SPD potentiometer counter-
clockwise.
Controller not calibrated correctly Refer to Steps 4 and 5 on page 5.
Open shunt field winding or wiring to
the motor shunt field
a
Check the motor shunt field and associated
circuitry for a loose connection or a broken
wire. Repair accordingly.
Motor field demagnetized
b
Replace the motor.
TABLE 6. TROUBLESHOOTING
INDICATION POSSIBLE CAUSE CORRECTIVE ACTION
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