Motor Generates Heat Abnormally; Motor Rotates In The Opposite Direction; Speed Greatly Differs From The Setting - Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual

6.6.4

Motor generates heat abnormally

Check
Possible cause
point
The motor fan is not working.
(Dust is accumulated.)
Motor
Phase to phase insulation of the motor is
insufficient.
Main The inverter output voltage (U, V, W) are
Circuit unbalanced.
Parameter The Pr.71 Applied motor setting is
setting incorrect.
— Motor current is too large
6.6.5

Motor rotates in the opposite direction

Check
Possible cause
point
Main The phase sequence of output terminals U,
Circuit V 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.
Input
signal, The torque command is negative during
parameter torque control under Vector control.
setting
6.6.6

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 the calibration parameter
Parameter
C2 to C7 settings are not appropriate.
setting
Pr.31 to Pr.36, and Pr.552 (frequency
jump) settings are not appropriate.
Load
Parameter The stall prevention (torque limit) function is
setting activated due to a heavy load.
Motor
Countermeasure
Clean the motor fan.
Improve the environment.
Check the insulation of the motor.
Check the output voltage of the inverter.
Check the insulation of the motor.
Check the Pr.71 Applied motor setting.
Refer to "6.6.11 Motor current is too large".
Countermeasure
Connect the output side terminals (terminals U, V, and W) correctly.
Check the connection. (STF: forward rotation, STR: reverse
rotation)
Check the polarity of the frequency command.
Check the torque command value.
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 (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.
Refer to
—
—
784
505
772
Refer to
55
68,
473
270
Refer to
—
116
407
482
408
—
235,
—
6. PROTECTIVE FUNCTIONS
6.6 Check first when you have a trouble
1
page
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502
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