Mitsubishi FR-E500 Drive

Fault Code and MeaningCause and Remedy
OC During Acc

Overcurrent shut-off during acceleration

Cause:

When the inverter output current reaches or exceeds approximately 200% of the rated current during acceleration, the protective circuit is activated to stop the inverter output.

Check points: Check for sudden acceleration. Check for output short-circuit/ground fault.



Remedy:


  • Increase the acceleration time.


Stedy Spd OC

Overcurrent shut-off during constant speed

Cause:

When the inverter output current reaches or exceeds approximately 200% of the rated current during constant speed, the protective circuit is activated to stop the inverter output.

Check points: Check for sudden load change. Check for output short-circuit/ground fault.



Remedy:


  • Keep load stable.


OC During Dec

Overcurrent shut-off during deceleration

Cause:

When the inverter output current reaches or exceeds approximately 200% of the rated current during deceleration (other than acceleration or constant speed), the protective circuit is activated to stop the inverter output.

Check points: Check for sudden speed reduction. Check for output short-circuit/ground fault. Check for too fast operation of motor’s mechanical brake.



Remedy:


  • Increase the deceleration time.

  • Adjust brake operation.


OV During Acc

Regenerative overvoltage shut-off during acceleration

Cause:

If regenerative energy causes the inverter’s internal main circuit DC voltage to reach or exceed the specified value, the protective circuit is activated to stop the inverter output. It may also be activated by a surge voltage generated in the power supply system.

Check points: Check for too slow acceleration.



Remedy:


  • Decrease the acceleration time.


Stedy Spd OV

Regenerative overvoltage shut-off during constant speed

Cause:

If regenerative energy causes the inverter’s internal main circuit DC voltage to reach or exceed the specified value, the protective circuit is activated to stop the inverter output. It may also be activated by a surge voltage generated in the power supply system.

Check points: Check for sudden load change.



Remedy:


  • Keep load stable.

  • Use the brake unit or high power factor converter (FR-HC) as required.


OV During Dec

Regenerative overvoltage shut-off during deceleration or stop

Cause:

If regenerative energy causes the inverter’s internal main circuit DC voltage to reach or exceed the specified value, the protective circuit is activated to stop the inverter output. It may also be activated by a surge voltage generated in the power supply system.

Check points: Check for sudden speed reduction.



Remedy:


  • Increase the deceleration time. (Set the deceleration time which matches the inertia moment of the load)

  • Decrease the braking duty.

  • Use the brake unit or high power factor converter (FR-HC) as required.


Motor Overload

Motor overload shut-off (electronic overcurrent protection)

Cause:

The electronic overcurrent protection in the inverter detects motor overheat due to overload or reduced cooling capability during constant-speed operation to stop the inverter output. When a multi-pole motor or two or more motors are run, provide a thermal relay in the output side of the inverter.

Check points: Check the motor for use under overload.



Remedy:


  • Reduce the load weight.

  • For the constant-torque motor, change the Pr. 71 setting to the constant-torque motor setting.


Inv. Overload

Inverter overload shut-off (electronic overcurrent protection)

Cause:

If a current of more than 150% of the rated output current flows and overcurrent shut-off does not occur (200% or less), inverse-time characteristics cause the electronic overcurrent protection to be activated to stop the inverter output in order to protect the output transistors.

Check points: Check the motor for use under overload.



Remedy:


  • Reduce the load weight.



H/Sink O/Temp



Fin overheat
If the cooling fin overheats, the overheat sensor is actuated to stop the inverter output.


Cause:



  • Check for too high ambient temperature.

  • Check for cooling fin clogging.




Remedy:


Set the ambient temperature to within the specifications.

Br. Cct. Fault



Brake transistor alarm detection
If a brake transistor fault occurs due to excessively large regenerative energy from the motor, that fault is detected to stop the inverter output. In this case, the inverter power must be switched off immediately.

Note: This function is activated only when the optional brake resistor is connected.


Cause:


Check for improper braking duty.



Remedy:


Change the inverter.

Please contact your sales representative.

Ground Fault



Output side ground fault overcurrent protection
This function stops the inverter output if a ground fault overcurrent flows due to a ground fault which occurred in the inverter’s output (load) side. Use Pr. 249 to set whether the protective function is to be activated.


Cause:


Check for a ground fault in the motor and connection cable.



Remedy:


Remedy the ground fault portion.

OH Fault



External thermal relay operation
If the external thermal relay designed for motor overheat protection or the internally mounted temperature relay in the motor switches on, the inverter output is stopped.

Note: This function is activated only when OH has been set for Pr. 183 “MRS terminal function selection”.


Cause:



  • Check for motor overheating.

  • Check that the value of 7 (OH signal) is set correctly in Pr. 183.




Remedy:


Reduce the load and operating duty.

Stll Prev STP



Stall prevention
The running frequency has fallen to 0 by stall prevention activated. (OL while stall prevention is being activated.)


Cause:


Check the motor for use under overload.



Remedy:


Reduce the load weight.

Option Fault



Option alarm
Stops the inverter output if an internal connector fault occurs.


Cause:


(Internal connector fault)



Remedy:


Please contact your sales representative.

Corrupt Memory



Parameter storage device alarm
A fault occurred in parameters stored (example: E²PROM fault).


Cause:


Check for too many number of parameter write times.



Remedy:


Please contact your sales representative.

PU Leave Out



Parameter unit disconnection
This function stops the inverter output if communication between the inverter and PU is suspended (e.g. PU disconnected).


Cause:



  • Check for loose fitting of the PU.

  • Check the Pr. 75 setting.




Remedy:


Fit the PU securely.

Retry No Over



Retry count exceeded
If operation cannot be resumed properly within the number of retries set, this function stops the inverter output.


Cause:


Find the cause of alarm occurrence.



Remedy:


Eliminate the cause of the error preceding this error indication.
CPU Fault

CPU error

Cause:

If the arithmetic operation of the built-in CPU does not end within a predetermined period, the inverter self-determines it as an alarm and stops the output.



Remedy:


  • Please contact your sales representative.


E. LF

Output phase failure protection

Cause:

This function stops the inverter output if one of the three phases (U, V, W) on the inverter’s output side (load side) results in open phase.

Check point:

– Check the wiring (Check the motor for a fault).

– Check that the capacity of the used motor is not smaller than the inverter capacity.



Remedy:


  • Wire the cables properly.


Fan Failure

Fan fault

Cause:

For the inverter which contains a cooling fan, this indication appears when the cooling fan stops due to a fault or operates differently from the setting of Pr. 244 “cooling fan operation selection”.

Check point: Check the cooling fan for a fault.



Remedy:


  • Change the fan.


OL

Stall prevention (overcurrent)

Cause:

If a current of more than 150% of the rated inverter current flows in the motor (during acceleration, constant-speed, or deceleration), this function modifies the frequency to prevent overcurrent shut-off.

Check point: Check the motor for use under overload.



Remedy:


  • The acceleration/deceleration time may change.

  • Increase the stall prevention operation level with Pr. 22 “stall prevention operation level”.

  • Disable stall prevention with Pr. 156 “stall prevention operation selection”.


oL

Stall prevention (overvoltage)

Cause:

During deceleration, if the regenerative energy of the motor increases too much to exceed the brake capability, this function stops the decrease in frequency to prevent overvoltage shut-off.

Check point: Check for sudden speed reduction.



Remedy:


  • The deceleration time may change.

  • Increase the deceleration time using Pr. 8 “deceleration time”.


PS

PU stop

Cause:

A stop made by pressing the [STOP/RESET] key of the PU has been set in Pr. 75 “PU stop selection”.

Check point: Check for a stop made by pressing the [STOP/RESET] key of the PU during DeviceNet operation.



Remedy:


  • Refer to page 88 of the manual.