Mitsubishi Electric FR-D720-0.2K-G, Instruction Manual

Page: 262 / 302

259
5
TROUBLES
HOOTING
Causes and corrective actions

Resetting the drive unit initializes the internal accumulated heat value of the electronic thermal relay function.

Resetting the drive unit initializes the internal accumulated heat value of the electronic thermal relay function.
Operation panel
indication
E.THT FR-PU07 Inv. Overload
Name Drive unit overload trip (electronic thermal O/L relay function)

Description
If the temperature of the output transistor element exceeds the protection level under the condition that a current not
less than the drive unit rated current flows and overcurrent trip does not occur (200% or less), the electronic thermal
relay activates to stop the drive unit output. (Overload capacity 150% 60s, 200% 0.5s)
Check point
 Check that acceleration/deceleration time is not too short.
 Check the motor for use under overload.
 Check for too high surrounding air temperature.
Corrective action
 Increase acceleration/deceleration time.
 Adjust the
Pr. 785 PM control torque boost
and
Pr. 795 DC brake torque boost
settings.
 Reduce the load weight.
 Set the surrounding air temperature to within the specifications.
Operation panel
indication
E.THM
FR-PU07 Motor Ovrload
Name
Motor overload trip

(electronic thermal O/L relay function)

Description
The electronic thermal relay function in the drive unit detects motor overheat due to overload or reduced cooling
capability during low-speed operation, and pre-alarm (TH display) is output when the integrated value reaches 85%
of the
Pr. 9 Electronic thermal O/L relay
setting, and the protection circuit is activated to stop the drive unit output when
the integrated value reaches the specified value.
Check point
 Check the motor for use under overload.
 Check that stall prevention operation setting is correct.
Corrective action
 Reduce the load weight.
 Adjust the Pr. 785 PM control torque boost and Pr. 795 DC brake torque boost settings.
 Check that stall prevention operation setting is correct. (Refer to page 83.)
Operation panel
indication
E.FIN FR-PU07 H/Sink O/Temp
Name
Heatsink overheat
Description
If the heatsink overheats, the temperature sensor is actuated and the drive unit trips.
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 or Pr. 192 (output terminal function selection) . (Refer to page 123.)
Check point
 Check for too high surrounding air temperature.
 Check for heatsink clogging.
 Check that the cooling fan is not stopped (Check that is not displayed on the operation panel).
Corrective action
 Set the surrounding air temperature to within the specifications.
 Clean the heatsink.
 Replace the cooling fan.