Motor Generates Abnormal Noise; Motor Generates Heat Abnormally; Motor Rotates In Opposite Direction; Speed Greatly Differs From The Setting - Mitsubishi Electric FR-A700 Instruction Manual

Check first when you have troubles
7.6.2

Motor generates abnormal noise

● No carrier frequency noises (metallic noises) are generated.
– Soft-PWM operation to change the motor tone into an unoffending complex tone is
factory-set to valid by the Pr. 72 "PWM frequency selection".
Adjust Pr. 72 "PWM frequency selection" to change the motor tone.
(When operating the inverter with the carrier frequency of 3kHz or more set in Pr. 72, the
carrier frequency will automatically decrease if the output current of the inverter exceeds
the value in parenthesis of the rated output current in appendix A. This may cause the
motor noise to increase. But it is not a fault.)
– Check for any mechanical looseness.
– Contact the motor manufacturer.
7.6.3

Motor generates heat abnormally

● Is the fan for the motor is running? (Check for accumulated dust.)
● Check that the load is not too heavy. Lighten the load.
● Check that the inverter output voltages (U, V, W) balanced.
● Check that the Pr.0 "Torque boost" setting is correct.
● Was the motor type set? Check the setting of Pr. 71 "Applied motor".
● When using any other manufacturer's motor, perform offline auto tuning. (Please refer to
section 6.12.3)
7.6.4

Motor rotates in opposite direction

● Check that the phase sequence of output terminals U, V and W is correct.
● Check that the start signals (forward rotation, reverse rotation) are connected properly.
(Refer to section 6.14.4.)
7.6.5

Speed greatly differs from the setting

● Check that the frequency setting signal is correct. (Measure the input signal level.)
● Check that Pr. 1, Pr. 2, Pr.19 and the calibration parameters C2 to C7 settings are correct.
● Check that the input signal lines are not affected by external noise. (Use shielded cables.)
● Check that the load is not too heavy. (The motor current can be read out by the operation
panel FR-DU07 .)
● Check that the Pr. 31 to Pr. 36 (frequency jump) settings are correct.
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Troubleshooting