Motor Rotates In The Opposite Direction; Speed Greatly Differs From The Setting; Acceleration/Deceleration Is Not Smooth - Mitsubishi Electric FR-A720-0.4K Instruction Manual

Check first when you have a trouble
5.5.5

Motor rotates in the opposite direction

Check
points
Main
Phase sequence of output terminals U, V and W is
Circuit incorrect.
The start signals (forward rotation, reverse rotation) are
connected improperly.
Input
The polarity of the frequency command is negative
signal
during the polarity reversible operation set by Pr. 73
Analog input selection.
Input
signal
Torque command is negative during torque control
Parameter under vector control.
setting
5.5.6

Speed greatly differs from the setting

Check
points
Frequency setting signal is incorrectly input.
Input
signal The input signal lines are affected by external EMI.
Pr. 1, Pr. 2, Pr. 18, calibration parameter C2 to C7 settings
Parameter
are improper.
Setting
Pr. 31 to Pr. 36 (frequency jump) settings are improper.
Load
Parameter
Stall prevention (torque limit) function is activated due to
Setting a heavy load.
Motor
5.5.7

Acceleration/deceleration is not smooth

Check
points
Acceleration/deceleration time is too short.
Torque boost (Pr. 0, Pr. 46, Pr. 112) setting is improper
under V/F control, so the stall prevention function is
activated.
Parameter
The base frequency setting and the motor characteristic
Setting
does not match.
Regeneration avoidance operation is performed
Load
Parameter
Stall prevention (torque limit) function is activated due to
Setting a heavy load.
Motor
422
Possible Cause
Possible Cause
Possible Cause
Countermeasures
Connect phase sequence of the output cables (terminal
U, V, W) to the motor correctly.
Check the wiring. (STF: forward rotation , STR: reverse
rotation)
Check the polarity of the frequency command.
Check the torque command value.
Countermeasures
Measure the input signal level.
Take countermeasures against EMI such as using
shielded wires for input signal lines.
Check the settings of Pr. 1 Maximum frequency, Pr. 2
Minimum frequency, Pr. 18 High speed maximum frequency.
Check the calibration parameter C2 to C7 settings.
Narrow down the range of frequency jump.
Reduce the load weight.
Set Pr. 22 Stall prevention operation level (Torque limit 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
Increase acceleration/deceleration time.
Increase/decrease Pr. 0 Torque boost setting value by
0.5% increments to the setting. Deactivate stall
prevention.
For V/F control, set Pr. 3 Base frequency, Pr. 47 Second V/F
(base frequency), and Pr.113 Third V/F (base frequency).
For vector control, set Pr.84 Rated motor frequency.
If the frequency becomes unstable during regeneration
avoidance operation, decrease the setting of Pr. 886
Regeneration avoidance voltage gain.
Reduce the load weight.
Set Pr. 22 Stall prevention operation level (Torque limit 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.
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