Yaskawa VCD 723 - Manual (Page 72)

4 Troubleshooting/Maintenance
66 Troubleshooting Flowcharts
9/15/93
Chart 7. Overcurrent ( oC ) Fault Indication
DOES OUTPUT
CURRENT EXCEED
200% OF RATING?
WITH VCD 723 IN STOPPED CON-
DITION, INCREASE ACCELERATION
TIME BY REPROGRAMMING PER PAC
DIAGRAM, IF OC TRIP OCCURS ONLY
DURING ACCELERATION.
OTHERWISE, REDUCE LOAD.
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
DOES OC TRIP
OCCUR, OR MAIN CIR-
CUIT CONTACTOR
TRIP, WHEN POWER
IS TURNED ON?
MACHINE JAMMED
OR MOTOR
FAILURE?
CLEAR JAM, OR
REPLACE MOTOR.
DISCONNECT WIRING
FROM OUTPUT TERMINALS
T1, T2 AND T3 AND
CHECK LOAD IMPEDANCE.
CHECK POWER
TRANSISTORS
(SEE TABLE 10).
ARE TRANSISTORS
DAMAGED?
REPLACE
DAMAGED POWER
TRANSISTORS.
WITH VCD 723 IN STOPPED
CONDITION, INCREASE
ACCELERATION TIME BY
REPROGRAMMING PER PAC
DIAGRAM.
DOES OC TRIP
STILL OCCUR? DECREASE
LOAD INERTIA.
MOTOR STARTED BY CONTACTS
WIRED BETWEEN VCD 723
AND MOTOR?
- REWIRE TO ELIMINATE MOTOR
FULL VOLTAGE STARTING.
- REPLACE DRIVE WITH
ONE OF LARGER CAPACITY.
ERRONEOUS OPERATION
DUE TO NOISE?
REMOVE NOISE SOURCE:
• CONNECT SURGE SUPPRESSOR
TO RELAY AND MAGNETIC CON-
TACTOR COILS.
• PROVIDE LINE FILTER TO
REMOVE NOISE ON INPUT
POWER LINE.
CONTROL PCB OR BASE
DRIVE PCB IS FAULTY.
REPLACE FAULTY BOARD.