Mitsubishi Electric FR-E720-0.4K Instruction Manual page 44

List of fault displays
Function Name
The output frequency has dropped to 1Hz as a
Stall prevention stop
result of deceleration due to the excess motor load.
A fault has occurred in the brake circuit, such as a
Brake transistor alarm
brake transistor breakage. (In this case, the
detection
inverter must be powered off immediately.)
Output side earth (ground) An earth (ground) fault has occurred on the
fault overcurrent at start inverter's output side (detected only at a start).
One of the three phases (U, V, W) on the inverter's
Output phase loss output side (load side) has been lost during
inverter operation.
External thermal relay The external thermal relay connected to the OH
operation signal has been activated.
A communication option has been connected
Option fault
while Pr.296 Password lock level = "0, 100".
Communication option A communication error has occurred on the
fault communication line of the communication option.
A fault, such as a contact fault, has occurred at the
contactor of the inverter or the plug-in option. The
Option fault
setting of the switch on the plug-in option, which is
for manufacturer setting, has been changed.
Operation of the component where parameters
Parameter storage
are stored (control circuit board) has become
device fault
abnormal.
The control circuit board and the main circuit
Internal board fault
board do not match.
 A communication error has occurred between
 The communication interval has exceeded the
PU disconnection
 The number of communication errors has
Operation restart within the set number of retries
Retry count excess
has failed.
An error has occurred in the CPU and in the
CPU fault
peripheral circuits.
A sequence error has occurred while the brake
Brake sequence fault
sequence function (Pr.278 to Pr.283) is valid.
Inrush current limit The resistor of the inrush current limit circuit has
circuit fault overheated.
A voltage (current) has been input to terminal 4
when the setting in Pr. 267 Terminal 4 input selection
Analog input fault
and the setting of voltage/current input switch are
different.
USB communication The communication has been broken for Pr. 548
fault
USB communication check time interval.
Internal circuit fault An internal circuit fault has occurred.
If faults other than the above appear, contact your sales representative.

Resetting the inverter initializes the internal cumulative heat value of the electronic thermal relay function.

This protective function is not available in the initial status.

Available for the three-phase power input models.
40
Description
the PU and the inverter.
permissible time period during RS-485
communication via the PU connector.
exceeded the number of retries.
Corrective action
Reduce the load. (Check the Pr. 22 Stall prevention operation level
setting.)
Replace the inverter.
Remedy the ground fault portion.
 Wire the cables properly.
 If the motor capacity is smaller than the inverter capacity,
choose the inverter and motor capacities that match.
 Reduce the load and operate less frequently.
 Even if the relay contacts are reset automatically, the inverter
will not restart unless it is reset.
 To apply the password lock when installing a communication
option, set Pr.296 Password lock level  "0, 100."
 If the problem still persists after taking the above measure,
contact your sales representative.
 Check the settings of the option functions.
 Connect the built-in option securely.
 Check the connections of the communication cables.
 Connect terminating resistors correctly.
 Connect the plug-in option securely.
 Take measures against noises if there are devices producing
excess electrical noises around the inverter.
If the situation does not improve after taking the above
measure, please contact your sales representative.
 Set the switch on the plug-in option, which is for manufacturer
setting, back to the initial setting. (
Instruction Manual of each option.)
Please contact your sales representative.
When performing parameter writing frequently for
communication purposes, set "1" in Pr. 342 Communication
EEPROM write selection to enable RAM write. Note that powering
OFF returns the inverter to the status before RAM write.
Please contact your sales representative.
(For parts replacement, consult the nearest Mitsubishi Electric
FA Center.)
 Connect the parameter unit cable securely.
 Check the communication data and communication settings.
 Increase the Pr. 122 PU communication check time interval
setting, or set "9999" (no communication check).
Eliminate the cause of the error preceding this error indication.
 Take measures against noises if there are devices producing
excess electrical noises around the inverter.
 Check the connection between the terminals PC and SD. (E6/
E7)
 If the situation does not improve after taking the above
measure, please contact your sales representative.
Check the parameter setting and check the wiring.
Configure a circuit where frequent power ON/OFF is not
repeated.
If the situation does not improve after taking the above
measure, please contact your sales representative.
Give a frequency command by a current input or set Pr.267
Terminal 4 input selection, and set the voltage/current input switch
to voltage input.
 Check the Pr.548 USB communication check time interval setting.
 Check the USB communication cable.
 Increase the Pr.548 USB communication check time interval
setting, or set "9999."
Please contact your sales representative.
Display
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