Mitsubishi Electric FR-A800, Instruction Manual

Page: 910 / 1042

Causes and corrective actions Protective functions
6 - 22
Operation panel
indication
E.THT FR-LU-08 Inv. overload trip
Name
Inverter overload trip
Description
When the temperature of the output transistor element exceeds the protection level while a
current flows at the rated output current level or higher without causing an overcurrent trip
(E.OC
첸
), the inverter output is stopped.(Permissible overload capacity 150% 60 s)
Check point
앫
Check that acceleration/deceleration time is not too short.
앫
Check that torque boost setting is not too large (small).
앫
Check that load pattern selection setting is appropriate for the load pattern of the using
machine.
앫
Check the motor for the use under overload.
앫
Check that the encoder wiring and the specifications (encoder power supply, resolution,
differential/complementary) are correct. Check also that the motor wiring (U, V, W) is correct
(under vector control).
Corrective action
앫
Set the acceleration/deceleration time longer.
앫
Adjust the torque boost setting.
앫
Set the load pattern selection setting according to the load pattern of the using machine.
앫
Reduce the load.
앫
Check the wiring and specifications of the encoder and the motor. Perform the setting
according to the specifications of the encoder and the motor (under vector control).
(Refer to page 2-61.)
Resetting the inverter initializes the internal cumulative heat value of the electronic thermal O/L relay function.
Operation panel
indication
E.THM FR-LU-08 Motor overload trip
Name
Motor overload trip
Description
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.
Check point
앫
Check the motor for the use under overload.
앫
Check that the setting of Pr. 71 "Applied motor" for motor selection is correct.
(Refer to page 5-434.)
앫
Check that the stall prevention operation setting is correct.
Corrective action
앫
Reduce the load.
앫
For a constant-torque motor, set the constant-torque motor in Pr. 71.
앫
Set the stall prevention operation level accordingly. (Refer to page 5-84.)
Resetting the inverter initializes the internal cumulative heat value of the electronic thermal O/L relay function.
Operation panel
indication
E.FIN FR-LU-08 Heatsink overheat
Name Heatsink overheat
Description
When the heatsink overheats, the temperature sensor activates, 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)" from Pr. 190 to Pr. 196 (output terminal function selection).
(Refer to page 5-361.)
Check point
앫
Check for too high surrounding air temperature.
앫
Check for heatsink clogging.
앫
Check that the cooling fan is not stopped.
(Check that "FN" is not displayed on the operation panel.)
Corrective action
앫
Set the surrounding air temperature to within the specifications.
앫
Clean the heatsink.
앫
Replace the cooling fan.