Motor Or Machine Generates Abnormal Noise - Mitsubishi Electric FR-D720S SC EC Instruction Manual

Troubleshooting
7.6.2

Motor or machine generates abnormal noise

Check points Possible Cause
Input signal
Parameter
Setting
Parameter
Setting
Others
Motor
7.6.3 Inverter generates abnormal noise
Check points Possible Cause
Fan
FR-D700 SC EC
Disturbance due to EMI when frequency
command is given from analog input (ter-
minal 2, 4).
No carrier frequency noises (metallic
noises) are generated.
Resonance occurs. (output frequency)
Resonance occurs. (carrier frequency)
Auto tuning is not performed under Gen-
eral-purpose magnetic flux vector control.
Gain adjustment during PID control is
insufficient.
Mechanical looseness
Operating with output phase loss
Contact the motor manufacturer.
Fan cover was not correctly installed when
a cooling fan was replaced.
Check first when you have troubles
Countermeasures
Take countermeasures against EMI.
Increase the Pr. 74 "Input filter time con-
stant" if steady operation cannot be per-
formed 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 pro-
duces an effect on avoiding the resonance
frequency of a mechanical system or a
motor.
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.
Adjust machine/equipment so that there is
no mechanical looseness.
Check the motor wiring.
Countermeasures
Install a fan cover correctly.
Refer to
Page
3-44
6-152
6-144
6-42
6-144
6-74
6-242
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Refer to
Page
8-8
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