Speed Greatly Differs From The Setting; Acceleration/Deceleration Is Not Smooth - Mitsubishi Electric FR-CS84-012 Instruction Manual

6.6.5

Speed greatly differs from the setting

Check Possible cause
point
The frequency setting signal is incorrect.
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 calibration parameters
Paramete
C2 to C7 settings are not appropriate.
r setting
Pr.31 to Pr.36 (frequency jump) settings
are not appropriate.
Load
Paramete The stall prevention function is activated
due to a heavy load.
r setting
Motor
6.6.6

Acceleration/deceleration is not smooth

Check Possible cause
point
The acceleration/deceleration time is too
short.
Torque boost (Pr.0) setting is improper
under the V/F control, so the stall
prevention function is activated.
Paramete
The base frequency does not match the
r setting
motor characteristics.
Regeneration avoidance operation is
performed.
Load
Paramete The stall prevention function is activated
due to a heavy load.
r setting
Motor
Countermeasure
Measure the input signal level.
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 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
Set the acceleration/deceleration time longer.
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.
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 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.
Refer to
page
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50
117
134
118
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119
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Refer to
page
93
193
194
199
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119
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6. PROTECTIVE FUNCTIONS
6.6 Check first when you have a trouble
1
2
3
5
6
7
8
9
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