Motor Or Machine Is Making Abnormal Acoustic Noise; Inverter Generates Abnormal Noise; Motor Generates Heat Abnormally - Mitsubishi Electric FR-F720P-0.75K Instruction Manual

Fr-f700p series
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Check first when you have a trouble
6.6.2

Motor or machine is making abnormal acoustic noise

When operating the inverter with the carrier frequency of 3kHz (6kHz during IPM motor control) 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 on page 150. This may cause the motor noise to increase. But it is not a fault.
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)
Parameter
Setting
Resonance occurs. (carrier frequency)
Gain adjustment during PID control is insufficient.
Mechanical looseness
Others
Contact the motor manufacturer.
Motor
Operating with output phase loss
6.6.3

Inverter generates abnormal noise

Check
points
Fan cover was not correctly installed when a cooling fan
Fan
was replaced.
6.6.4

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. (V/F control,
Setting
Simple magnetic flux vector control)
Motor current is large.
136
Possible Cause
Possible Cause
Possible Cause
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.
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.
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. (V/F control,
Simple magnetic flux vector control)
Refer to "6.6.11 Motor current is too large"
Refer
to
page
97
96
92
96
100
Refer
to
page
146
Refer
to
page
142
95
139

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