Motor Rotates In The Opposite Direction; Speed Greatly Differs From The Setting; Acceleration/Deceleration Is Not Smooth - Mitsubishi Electric 800 Series Instruction Manual

2.6.5

Motor rotates in the opposite direction

Check
point
Main The phase sequence of output terminals U, V
circuit and W is incorrect.
The start signals (STF and STR signals) are
connected improperly.
Input
The polarity of the frequency command is
signal
negative during the polarity reversible
operation set by Pr.73 Analog input
selection.
2.6.6

Speed greatly differs from the setting

Check
point
The frequency setting signal is incorrect. Measure the input signal level.
Input
The input signal lines are affected by
signal
external EMI.
Pr.1 Maximum frequency, Pr.2
Minimum frequency, Pr.18 High speed
maximum frequency, and the
Parameter
calibration parameter C2 to C7 settings
setting
are not appropriate.
Pr.31 to Pr.36 (frequency jump) settings
are not appropriate.
Load
Parameter The stall prevention (torque limit) function
setting is activated due to a heavy load.
Motor
2.6.7

Acceleration/deceleration is not smooth

Check
point
The acceleration/deceleration time is too
short.
The torque boost (Pr.0, Pr.46) setting is
not appropriate under V/F control, so the
Parameter
stall prevention function is activated.
setting
The base frequency does not match the
motor characteristics.
Regeneration avoidance operation is
performed.
Load
Parameter The stall prevention (torque limit) function
setting is activated due to a heavy load.
Motor
35
2. Protective Functions
2.6 Check first when you have a trouble
Possible cause
Possible cause
Possible cause
Connect the output side terminals (terminals U, V, and W) correctly.
Check the connection. (STF/DI0: forward rotation, STR/DI1: reverse rotation)
Check the polarity of the frequency command.
Take countermeasures against EMI, such as using shielded wires for input signal
lines.
Check the settings of Pr.1, Pr.2, and Pr.18.
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. (If Pr.22 is set too high, an overcurrent trip (E.OC[]) is likely to occur.)
Check the capacities of the inverter and the motor.
Increase the acceleration/deceleration time.
Increase/decrease the Pr.0 Torque boost setting value by 0.5% increments so that
stall prevention does not occur.
Under V/F control, set Pr.3 Base frequency and Pr.47 Second V/F (base
frequency).
If the frequency becomes unstable during regeneration avoidance operation,
decrease the setting of Pr.886 Regeneration avoidance voltage gain.
Reduce the load.
Set Pr.22 Stall prevention operation level (Torque limit level) higher according
to the load. (If Pr.22 is set too high, an overcurrent trip (E.OC[]) is likely to occur.)
Check the capacities of the inverter and the motor.
Countermeasure
Countermeasure
Countermeasure