Mitsubishi Electric FR-F800 Series Instruction Manual page 603

Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
*1 Resetting the inverter initializes the internal cumulative heat value of the electronic thermal relay function.
Operation panel
indication
Name
Description
Check point
Corrective action
*2 Resetting the inverter initializes the internal cumulative heat value of the electronic thermal relay function.
Operation panel
indication
Name
Description
Check point
Corrective action
602
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
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E.OV3
Regenerative overvoltage trip during deceleration or stop
If regenerative power causes the inverter's internal main circuit DC voltage to reach or exceed the specified
value, the protection circuit is activated to stop the inverter output. The circuit may also be activated by a surge
voltage produced in the power supply system.
• Check for sudden speed reduction.
• Check if the stall prevention operation is frequently activated in an application with a large load inertia.
• Set the deceleration time longer. (Set the deceleration time which matches the moment of inertia of the load.)
• Make the brake cycle longer.
• Use the regeneration avoidance function (Pr.882 to Pr.886). (Refer to
• Use the brake unit, multifunction regeneration converter (FR-XC), or power regeneration common converter
(FR-CV) as required.
• Set Pr.154 Voltage reduction selection during stall prevention operation = "10 or 11". (Refer to
E.THT
Inverter overload trip (electronic thermal relay function)
If the temperature of the output transistor elements exceeds the protection level with a rated output current or
higher flowing without the overcurrent trip (E.OC[]), the inverter output is stopped. (Overload capacity 120% 60 s)
• Check that acceleration/deceleration time is not too short.
• Check that torque boost setting is not too large (small).
• Check that load pattern selection setting is appropriate for the load pattern of the machine.
• Check the motor for the use under overload.
• Set the acceleration/deceleration time longer.
• Adjust the torque boost setting.
• Set the load pattern selection setting according to the load pattern of the using machine.
• Reduce the load.
E.THM
Motor overload trip (electronic thermal relay function)
The electronic thermal O/L relay function in the inverter detects motor overheat, which is caused by overload or
reduced cooling capability during low-speed operation. When the cumulative heat value reaches 85% of the Pr.9
Electronic thermal O/L relay setting, pre-alarm (TH) is output. When the accumulated value reaches the
specified value, the protection circuit is activated to stop the inverter output. When the inverter is used to drive a
dedicated motor, such as a multiple-pole motor, or several motors, the motor cannot be protected by the
electronic thermal O/L relay. Install an external thermal relay on the inverter output side.
• Check the motor for the use under overload.
• Check that the setting of Pr.71 Applied motor for motor selection is correct. (Refer to
• Check that the stall prevention operation setting is correct.
• Reduce the load.
• For a constant-torque motor, set the constant-torque motor in Pr.71.
• Set the stall prevention operation level accordingly. (Refer to
E.FIN
Heat sink overheat
When the heat sink overheats, the temperature sensor is activated, and the inverter output is stopped.
The FIN signal can be output when the temperature becomes approximately 85% of the heat sink overheat
protection operation temperature.
For the terminal used for the FIN signal output, assign the function by setting "26 (positive logic) or 126 (negative
logic)" from Pr.190 to Pr.196 (output terminal function selection). (Refer to
• Check for too high surrounding air temperature.
• Check for heat sink clogging.
• Check that the cooling fan is not stopped. (Check that FN is not displayed on the operation panel.)
• Set the surrounding air temperature to within the specifications.
• Clean the heat sink.
• Replace the cooling fan.
search engine
FR-LU08 indication OV During Dec
page 572.)
FR-LU08 indication Inv. overload trip
*1
FR-LU08 indication Motor overload trip
*2
page 290.)
FR-LU08 indication Heatsink overheat
page
page 290.)
page 379.)
330.)