Mitsubishi Electric FR-CS84-012 Instruction Manual page 217

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
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
*3 Available only for three-phase power input specification model.
216
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
E.THM
Motor overload trip (electronic thermal O/L relay function)
The electronic thermal 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 integrated 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 motors cannot be protected by the electronic thermal
O/L relay. In such cases, install an external thermal relay on the inverter output side.
• Check if the motor is not used 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 Applied motor.
• Set the stall prevention operation level accordingly. (Refer to
E.FIN
Heatsink overheat
When the heatsink 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 heatsink 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)" in Pr.195 (output terminal function selection). (Refer to
• Check for too high surrounding air temperature.
• Check for heatsink clogging.
• Check that the cooling system is not stopped.
• Set the surrounding air temperature to within the specifications.
• Clean the heatsink.
• If the problem still persists after taking the above measure, contact your sales representative.
E.UVT
Undervoltage
If the power supply voltage of the inverter decreases, the control circuit will not perform normal functions. In
addition, the motor torque will be insufficient and/or heat generation will increase. To prevent this, if the power
supply voltage decreases to about 150 VAC (300 VAC for the 400 V class) or below, this function shuts off the
inverter output. (Refer to page
• Check if a high-capacity motor is driven.
• Check the devices on the power supply line such as the power supply itself.
• If the problem still persists after taking the above measure, contact your sales representative.
E.ILF
*3
Input phase loss
When Pr.872 Input phase loss protection selection is enabled ("1") and one of the three-phase power input
is lost, the inverter output is shut off. Whether the protective function is used or not is set with Pr.872.
It may function if phase-to-phase voltage of the three-phase power input becomes largely unbalanced.
• Check if a high-capacity motor is driven.
• Check that phase-to-phase voltage of the three-phase power input is not largely unbalanced.
• Wire the cables properly.
• Check the Pr.872 setting.
FR-LU08 indication
*2
FR-LU08 indication
FR-LU08 indication
159.)
FR-LU08 indication
Motor Ovrload
page 147.)
page 119.)
H/Sink O/Temp
page 126.)
Under Voltage
Input phase loss