Acceleration/Deceleration Is Not Smooth - Mitsubishi Electric FR-D720S SC EC Instruction Manual

Troubleshooting
7.6.7

Acceleration/deceleration is not smooth

Check points Possible Cause
Parameter
Setting
FR-D700 SC EC
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.
The base frequency does not match the
motor characteristics.
Stall prevention function is activated due
to a heavy load.
Regeneration avoidance operation is per-
formed
Check first when you have troubles
Countermeasures
Increase acceleration/deceleration time.
Increase/decrease Pr. 0 "Torque boost"
setting value by 0.5% increments to the
setting.
For V/f control, set Pr. 3 "Base frequency"
and Pr. 47 "Second V/f (base frequency)".
For general-purpose magnetic flux vector
control, set Pr. 84 "Rated motor fre-
quency".
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.
If the frequency becomes unstable during
regeneration avoidance operation,
decrease the setting of Pr. 886 "Regene-
ration avoidance voltage gain".
Refer to
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