Mitsubishi Electric FR-E720-0.1K Instruction Manual page 46

8.2 List of fault displays
When a fault occurs in the inverter, the inverter trips and the PU display automatically changes to one of the following fault or
alarm indications.
The error message shows an operational error. The inverter output is not shut off.
Warnings are messages given before faults occur. The inverter output is not shut off.
Alarms warn the operator of failures with output signals. The inverter output is not shut off.
When faults occur, the protective functions are activated to inverter trip and output the fault signals.
Function Name
Operation has been attempted during the
Operation panel lock
operation panel lock.
Reading/writing of a password-restricted
Password locked
parameter has been attempted.
 Parameter setting has been attempted although
parameter writing is set to be disabled.
 Overlapping range has been set for the
Write disable error
frequency jump.
 PU and the inverter cannot make normal
communication.
Parameter writing has been attempted while a
Write error during
value other than "2" is set in Pr. 77 Parameter write
operation
selection and the STF (STR) is ON.
Analog input bias and gain calibration values have
Calibration error
been set too close.
 Parameter setting has been attempted in the
External or NET operation mode when Pr.77
Mode designation error Parameter write selection is not "2."
 Parameter writing has been attempted when the
command source is not at the operation panel.
The reset signal (RES signal) is ON.
Inverter reset
(Inverter output is shutoff.)
Stall prevention The overcurrent stall prevention has been
(overcurrent) activated.
The overvoltage stall prevention function has been
Stall prevention activated.
(overvoltage) (This warning is also output during the
regeneration avoidance operation.)
The regenerative brake duty has reached 85% of
Regenerative brake pre-
the Pr. 70 Special regenerative brake duty setting or
alarm 
higher.
The cumulative value of the electronic thermal O/L
Electronic thermal relay
relay has reached 85% of the Pr. 9 Electronic
function pre-alarm
thermal O/L relay setting or higher.
PU stop
during the External operation.
Maintenance signal The cumulative energization time has exceeded
output the maintenance output timer set value.
The voltage at the main circuit power has been
Undervoltage
lowered.
The cooling fan is at a standstill although it is
Fan alarm required to be operated. The cooling fan speed
has decelerated.
Description
on the operation panel has been pressed
List of fault displays
Corrective action
Press for 2s to release the lock.
Enter the password in Pr. 297 Password lock/unlock to unlock the
password function before operating.
 Check the setting of Pr. 77 Parameter write selection.
 Check the settings of Pr. 31 to Pr. 36 (frequency jump).
 Check the connection of PU and the inverter.
 Set "2" in Pr. 77 Parameter write selection.
 After stopping the operation, set parameters.
Check the settings of calibration parameters C3, C4, C6 and C7
(calibration functions).
 After setting the operation mode to the "PU operation mode,"
set parameters.
 Set "2" in Pr.77 Parameter write selection.
 Disconnect FR Configurator2 (USB connector) and the
parameter unit (FR-PU04/FR-PU07), then set Pr. 551 PU mode
operation command source selection = "9999 (initial setting)."
 Set Pr. 551 PU mode operation command source selection = "4."
 Turn OFF the reset command.
 Increase or decrease the Pr. 0 Torque boost setting by 1% and
check the motor status.
 Set the acceleration/deceleration time longer.
 Reduce the load. Try Advanced magnetic flux vector control or
General-purpose magnetic flux vector control.
 Check the peripheral devices for faults.
 Adjust the Pr. 13 Starting frequency setting. Change the Pr. 14
Load pattern selection setting.
 Set the stall prevention operation current in Pr. 22 Stall
prevention operation level. (The acceleration/deceleration time
may change.) Increase the stall prevention operation level
with Pr. 22 Stall prevention operation level, or disable stall
prevention with Pr. 156 Stall prevention operation selection.
(Operation at OL occurrence can be selected using Pr. 156
Stall prevention operation selection.)
Set the deceleration time longer.
 Set the deceleration time longer.
 Check the Pr.30 Regenerative function selection and Pr. 70 Special
regenerative brake duty settings.
 Reduce the load and frequency of operation.
 Set an appropriate value in Pr. 9 Electronic thermal O/L relay.
Turn the start signal OFF and release with
Setting "0" in Pr. 503 Maintenance timer erases the signal.
Investigate the devices on the power supply line such as the
power supply itself.
Check for fan failure. Please contact your sales representative.
Display
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