Motor Generates Heat Abnormally; Motor Rotates In The Opposite Direction; Speed Greatly Differs From The Setting; Acceleration/Deceleration Is Not Smooth - Mitsubishi Electric 700 Series Instruction Manual

Check first when you have a trouble
6.5.4

Motor generates heat abnormally

Check
points
Motor fan is not working
Motor
(Dust is accumulated.)
Phase to phase insulation of the motor is insufficient.
Main
The inverter output voltage (U, V, W) are unbalanced.
Circuit
Parameter
The Pr. 71 Applied motor setting is wrong.
Setting
—
Motor current is large.
6.5.5

Motor rotates in the opposite direction

Check
points
Main
Phase sequence of output terminals U, V and W is
Circuit incorrect.
Parameter
Pr. 40 RUN key rotation direction selection setting is
Setting incorrect.
6.5.6

Speed greatly differs from the setting

Check
points
Parameter
Pr. 1, Pr. 2, Pr. 18 settings are improper.
Setting
Pr. 31 to Pr. 36 (frequency jump) settings are improper.
Load
Parameter
Stall prevention function is activated due to a heavy
Setting load.
Motor
6.5.7

Acceleration/deceleration is not smooth

Check
points
The base frequency does not match the motor
characteristics.
Stall prevention function is activated due to a heavy
Parameter
load.
Setting
Acceleration/deceleration time is too short.
Torque boost (Pr. 0, Pr. 46) setting is improper under V/F
control, so the stall prevention function is activated.
Regeneration avoidance operation is performed
206
Possible Cause
Possible Cause
Possible Cause
Possible Cause
Countermeasures
Clean the motor fan.
Improve the environment.
Check the insulation of the motor.
Check the output voltage of the inverter.
Check the insulation of the motor.
Check the Pr. 71 Applied motor setting.
Refer to "6.5.11 Motor current is too large"
Countermeasures
Connect phase sequence of the output cables (terminal
U, V, W) to the motor correctly
Check the Pr. 40 setting.
Countermeasures
Check the settings of Pr. 1 Maximum frequency, Pr. 2
Minimum frequency, Pr. 18 High speed maximum frequency.
Narrow down the range of frequency jump.
Reduce the load weight.
Set Pr. 22 Stall prevention operation level higher according
to the load. (Setting Pr. 22 too large may result in
frequent overcurrent trip (E.OC ).)
Check the capacities of the inverter and the motor.
Countermeasures
For V/F control, set Pr. 3 Base frequency and Pr. 47 Second
V/F (base frequency).
For Advanced magnetic flux vector control or General-
purpose magnetic flux vector control, set Pr. 84 Rated
motor frequency.
Reduce the load weight.
Set Pr. 22 Stall prevention operation level higher according
to the load. (Setting Pr. 22 too large may result in
frequent overcurrent trip (E.OC ).)
Check the capacities of the inverter and the motor.
Increase acceleration/deceleration time.
Increase/decrease Pr. 0 Torque boost setting value by
0.5% increments to the setting.
If the frequency becomes unstable during regeneration
avoidance operation, decrease the setting of Pr. 886
Regeneration avoidance voltage gain.
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