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Causes and corrective actions
*1 Resetting the inverter initializes the internal thermal integrated data of the electronic thermal relay function.
Operation Panel
Indication
E.THT
FR-PU04
FR-PU07
Inv. Overload
Name
Inverter overload trip (electronic thermal relay function) *1
Description
If a current not less than 150% of the rated output current flows and overcurrent trip does not occur
(220% or less), the electronic thermal relay activate to stop the inverter output in order to protect the
output transistors. (Overload capacity 150% 60s inverse-time characteristics)
Check point
y Check that acceleration/deceleration time is not too short.
y Check that torque boost setting is not too large (small).
y Check that load pattern selection setting is appropriate for the load pattern of the using machine.
y Check the motor for use under overload.
Corrective action
y Increase acceleration/deceleration time.
y Adjust the torque boost setting.
y Set the load pattern selection setting according to the load pattern of the using machine.
y Reduce the load weight.
Operation Panel
Indication
E.THM
FR-PU04
FR-PU07
Motor Ovrload
Name
Motor overload trip (electronic thermal relay function) *1
Description
The electronic thermal relay function in the inverter detects motor overheat due to overload or reduced
cooling capability during constant speed operation and pre-alarm (TH display) is output when the I
2
t
value reaches 85% of the Pr. 9 Electronic thermal O/L relay setting and the protection circuit is activated
to stop the inverter output when the I
2
t value reaches the specified value. When running a special
motor such as a multi-pole motor or two motors, provide a thermal relay on the inverter output side
since such motor(s) cannot be protected by the electronic thermal relay function.
Check point
y Check the motor for use under overload.
y Check that the setting of Pr. 71 Applied motor for motor selection is correct. (Refer to Chapter 4 of
the Instruction Manual (Applied).)
y Check that stall prevention operation setting is correct.
Corrective action
y Reduce the load weight.
y For a constant-torque motor, set the constant-torque motor in Pr. 71 Applied motor.
y Check that stall prevention operation setting is correct. (Refer to Chapter 4 of the Instruction
Manual (Applied).)
Operation Panel
Indication
E.FIN
FR-PU04
FR-PU07
H/Sink O/Temp
Name
Heatsink overheat
Description
If the heatsink overheats, the temperature sensor is actuated to stop the inverter output.
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 any of Pr. 190 to Pr. 196 (output terminal function selection). (Refer to Chapter 4 of
the Instruction Manual (Applied))
Check point
y Check for too high surrounding air temperature.
y Check for heatsink clogging.
y Check that the cooling fan is stopped. (Check that is displayed on the operation panel.)
Corrective action
y Set the surrounding air temperature to within the specifications.
y Clean the heatsink.
y Replace the cooling fan.