Speed Greatly Differs From The Setting; Acceleration/Deceleration Is Not Smooth - Mitsubishi Electric FR-F820-00077 Instruction Manual

Check first when you have a trouble
6.6.6

Speed greatly differs from the setting

Check
points
Input
signal
Parameter
setting
Load
Parameter
setting
Motor
6.6.7

Acceleration/deceleration is not smooth

Check
points
Parameter
setting
Load
Parameter
setting
Motor
6 - 38
Possible cause
Frequency setting signal is incorrectly input. Measure the input signal level.
The input signal lines are affected by
external EMI.
Pr. 1 "Maximum frequency," Pr. 2 "Minimum
frequency", Pr. 18 "High speed maximum
frequency", and calibration parameters C2
to C7 settings are improper.
Pr. 31 to Pr. 36, Pr. 552 (frequency jump)
settings are improper.
Stall prevention function is
activated due to a heavy load.
Possible cause
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.
Regeneration avoidance operation is
performed
Stall prevention function is
activated due to a heavy load.
Countermeasure
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 parameters C2 to C7
settings.
Narrow down the range of frequency jump.
Reduce the load weight.
Set Pr. 22 "Stall prevention operation 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
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",
Pr. 47 "Second V/F (base frequency)",.
Under Advanced magnetic flux vector control
or PM motor 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"
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.
Protective functions
Refer to
page
⎯
3-6
5-176
5-266
5-178
⎯
5-180
⎯
Refer to
page
5-102
5-535
5-537
5-41
5-560
⎯
5-180
⎯