Motor Or Machine Is Making Abnormal Acoustic Noise; Inverter Generates Abnormal Noise; Motor Generates Heat Abnormally - Mitsubishi Electric FR-A720-0.4K Instruction Manual

5.5.2

Motor or machine is making abnormal acoustic noise

Even if the carrier frequency (Pr. 72) is set to a value higher than 3kHz for a 55K or lower capacity inverter, the carrier
frequency is automatically lowered to as low as 2kHz in an overloaded operation at a low speed (output frequency lower than
3Hz). Acoustic noise from the motor increases, but it is not a fault. (Refer to page 284 for Pr. 72)
Check
points
Input
signal
Disturbance due to EMI when frequency command is
Parameter given from analog input (terminal 1, 2, 4).
Setting
No carrier frequency noises (metallic noises) are
generated.
Resonance occurs. (output frequency)
Resonance occurs. (carrier frequency)
Parameter
Setting
Auto tuning is not performed under Advanced magnetic
flux vector control, Real sensorless vector control, or
vector control.
Gain adjustment during PID control is insufficient.
The gain is too high under Real sensorless vector
control or vector control.
Mechanical looseness
Others
Contact the motor manufacturer.
Motor
Operating with output phase loss
5.5.3

Inverter generates abnormal noise

Check
points
Fan cover was not correctly installed when a cooling fan
Fan
was replaced.
5.5.4

Motor generates heat abnormally

Check
points
Motor fan is not working
Motor
(Dust is accumulated.)
Phase to phase insulation of the motor is insufficient.
Main
The inverter output voltage (U, V, W) are unbalanced.
Circuit
Parameter
The Pr. 71 Applied motor setting is wrong.
Setting
—
Motor current is large.
Possible Cause
Possible Cause
Possible Cause
Check first when you have a trouble
Countermeasures
Take countermeasures against EMI.
Increase the Pr. 74 Input filter time constant if steady
operation cannot be performed due to EMI.
In the initial setting, Pr. 240 Soft-PWM operation selection is
enabled to change motor noise to an unoffending
complex tone. Therefore, no carrier frequency noises
(metallic noises) are generated.
Set Pr. 240 = "0" to disable this function.
Set Pr. 31 to Pr. 36 (Frequency jump).
When it is desired to avoid resonance attributable to the
natural frequency of a mechanical system, these
parameters allow resonant frequencies to be jumped.
Change Pr. 72 PWM frequency selection setting.
Changing the PWM carrier frequency produces an effect
on avoiding the resonance frequency of a mechanical
system or a motor.
Set a notch filter.
Perform offline auto tuning.
To stabilize the measured value, change the proportional
band (Pr. 129) to a larger value, the integral time (Pr. 130)
to a slightly longer time, and the differential time (Pr. 134)
to a slightly shorter time.
Check the calibration of set point and measured value.
During speed control, check the setting of Pr. 820 (Pr.
830) speed control P gain.
During torque control, check the setting of Pr. 824 (Pr.
834) torque control P gain.
Adjust machine/equipment so that there is no
mechanical looseness.
Check the motor wiring.
Countermeasures
Install the fan cover correctly.
Countermeasures
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 "5.5.11 Motor current is too large"
Refer
to
page
52
292
284
158
284
118
189
361
105
130
—
—
Refer
to
page
431
5
Refer
to
page
—
—
429
187
424
421