7-9
7
îš‹ Alarm Detection
Alarms are Inverter protection functions that indicate unusual conditions without switching off the drive and
operating the fault output contact. The alarm automatically disappears when its cause is eliminated.
During an alarm condition, the Digital Operator/LED Monitor alarm 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 7.3 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.
Control sequence is faulty.
Check external sequence logic, so
that 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 Set-
ting (L2-05).
• The MC of the inrush current pre-
vention circuit was opened.
• The control power supply voltage
was below the CUV level.
UV Alarm is detected only, when the
drive is in stop condition
For the probable reasons 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 over-
voltage detection level.
200 V class: 410 VDC
400 V class: 820 VDC
An OV Alarm is detected only, when
the drive is in stop 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 cool-
ing fin exceeded the temperature pro-
grammed in L8-02.
Enabled when L8-03 = 3.
The ambient temperature is too high.
Check for dirt build-up on the fans
or heatsink.
There is a heat source nearby.
Reduce the ambient temperature
around the Inverter
The Inverter cooling fan(s) has
stopped.
Replace the cooling fan(s).
OL3
Car Stuck
(flashing)
Overtorque Detection 1
The Inverter’s output current (V/f con-
trol) or the output torque (Vector con-
trol) exceeded L6-02 for longer than
the time set in L6-03 and L6-01is set to
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 con-
trol) or the output torque (Vector con-
trol) exceeded L6-02 for longer than
the time set in L6-03 and L6-01 is set to
1 or 2.
Motor was overloaded
Ensure the values in L6-05 and L6-
06 are appropriate.
Check application/machine status
to eliminate fault.
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