15
CHAPTER 4 TROUBLE SHOOTING
Inverter is provided with functions of warning and protection such as over voltage, low voltage and over current.
Once fault occurs, protection function shall act, inverter output stops, fault contactor act and also free running of
motor shall stop. For causes and corrective measures of fault, display of fault shall be taken for reference. Fault
records shall be stored into computer memory inside inverter (fault records for recent six times shall be available),
and records shall be read at digital control keypad.
Attention shall be paid that, pressing RESET after fault shall only be available after fault has been eliminated.
4.1 Alarm and corrective measures
Display Descriptions of fault
Corrective measures
Oc
Inverter detects Over current at
output side.
1.Check rated current of motor complies with that of
inverter.
2.Check that there is no short circuit in U, V, and W.
3.Check that no short circuit or grounding occur to
connection of motor.
4.Check that screws are securely tightened to inverter.
5.Increase acceleration time (1-09, 1-11).
6.Check there is no over load to motor.
Ou
Inverter detects Over voltage at DC
high voltage side.
1.Check input voltage is within rated voltage range of
inverter, and see that no voltage surge occurs.
2.If over voltage occurs at DC high voltage side of inverter
caused by inertia back up voltage, deceleration time shall
be increased.
OH
Inverter detects over heat, exceeding
protection level.
1.Check that ambient environment is not over heat.
2.Check radiator and air fan is running.
3.Check enough clearance for air flowing is provided to to
inverter
OHc
The inverter detects that the internal
charging resistor is too hot and
exceeds the level.
Factory maintenance
Lu
DC high voltage side over low inside
inverter.
1.Check power supply voltage is correct.
2.Check no sudden heavy load.
OL
Output current exceeds allowable
current of inverter. 60 sec shall be in
station if 150% of rated current of
inverter is output.
1.Check motor over load.
2.Decrease torque (7-02) to improve set value.
3.Increase output capacity of inverter.
OL1
Inner electric relay protection acts
1.Check motor over load.
2Check rated current (07-00) of motor is proper.
3.Check electric relay function setting.
4.Increase motor capacity.
