Contents

Alarm Detection
Alarms are Inverter protection function that do not operate the fault contact output. The system will automatically
return to its original status when the cause of the alarm has been removed.
During an alarm condition, the Digital Operator/Monitor display flashes and an alarm output is generated at
the multi-function outputs (H2-01 to H2-03) if programmed
When an alarm occurs, take appropriate countermeasures according to the table below.
Table 6.22 Alarm Detection
Display Meaning Probable causes Corrective Actions
EF
External Fault
(flashing)
Forward/Reverse Run Commands
Input Together
Both the forward and the reverse run
commands are input simultaneously
for 500ms or more. This alarm stops
the motor.
The external forward and reverse
command were input simultaneously.
Check external sequence logic, so
only one input is received at a
time.
UV
DC Bus Undervolt
(flashing)
DC Bus Undervoltage
The following conditions occurred
• The DC bus voltage was below the
Undervoltage Detection Level Setting
(L2-05).
• The MC of the inrush current prevention
circuit opened.
• The control power supply voltage
when below the CUV level.
UV Alarm is only detected when the
drive is in a stopped condition
For the probable causes please have a
look at UV1, UV2 and UV3 in table
7.1.
For the corrective actions please
have a look at UV1, UV2 and
UV3 in table 7.1
OV
DC Bus Overvolt
(flashing)
DC Bus Overvoltage
The DC bus voltage exceeded the
overvoltage detection level.
200 V class: 410 VDC
400 V class: 820 VDC
OV Alarm is only detected when the
drive is in a stopped condition
The power supply voltage is too high.
Check the power supply and
decrease the voltage to meet the
Inverter’s specifications
OH
Heatsnk Overtmp
(flashing)
Heatsink Overheat
The temperature of the Inverter's cooling
fin exceeded the temperature programmed
in L8-02.
Enabled when L8-03 = 3
The ambient temperature is too high.
There is a heat source nearby.
The Inverter cooling fan(s) has
stopped.
Check for dirt build-up on the fans
or heatsink.
Reduce the ambient temperature
around the Inverter
Replace the cooling fan(s).
OL3
Car Stuck
(flashing)
Overtorque Detection 1
The Inverter’s output current (V/f
control) or the output torque (Vector
control) exceeded L6-02 for longer
then the time set in
L6-03 and L6-01 = 1 or 2
Motor was overloaded
Ensure the values in L6-02 and
L6-03 are appropriate.
Check application/machine status
to eliminate fault.
OL4
Car Stuck
(flashing)
Overtorque Detection 1
The Inverter’s output current (V/f
control) or the output torque (Vector
control) exceeded L6-02 for longer
then the time set in
L6-03 and L6-01 = 1 or 2
Motor was overloaded
Ensure the values in L6-05 and
L6-06 are appropriate.
Check application/machine status
to eliminate fault.
6-8