174
Motor noise, EMI measures, mechanical resonance
4.16 Motor noise, EMI measures, mechanical resonance
4.16.1 PWM carrier frequency and soft-PWM control (Pr. 72, Pr. 240)
(1) PWM carrier frequency changing
(Pr. 72)
You can change the PWM carrier frequency of the inverter.
Changing the PWM carrier frequency produces an effect on avoiding the resonance frequency of a mechanical system or
motor or on EMI measures or on leakage current reduction caused by the PWM switching.
(2) Soft-PWM control
(Pr. 240)
Soft-PWM control is a control method that changes the motor noise from a metallic tone into an unoffending complex tone.
Purpose of Use
Parameter that should be Set
Refer to Page
Reduction of the motor noise
Measures against EMI and leakage
currents
Carrier frequency and
Soft-PWM selection
Pr. 72, Pr. 240
Reduce mechanical resonance
Speed smoothing control
Pr. 653
You can change the motor sound.
Parameter
Number
Name
Initial Value
Setting Range
Description
72
PWM frequency selection
1
0 to 15
You can change the PWM carrier frequency.
The setting is in [kHz].
Note that 0 indicates 0.7kHz and 15
indicates 14.5kHz.
240
Soft-PWM operation
selection
1
0
Soft-PWM is invalid
1
When
Pr. 72
= "0 to 5", soft-PWM is valid.
The above parameters can be set when
Pr.160 User group read selection
= "0".
The above parameters allow their settings to be changed during operation even if "0" (initial value) is set in
Pr. 77 Parameter write selection
.
NOTE
Decreasing the PWM carrier frequency effect on EMI measures and on leakage current reduction, but increases
motor noise.
When PWM carrier frequency is set to 1kHz or less (
Pr.72
≤
1), fast response current limit may function prior to stall
prevention operation due to increase in ripple currents, resulting in insufficient torque. In such case, set fast-
response current limit operation invalid using
Pr. 156 Stall prevention operation selection
.
When setting 2kHz or more in
Pr. 72
to perform operation in the place where the surrounding air temperature
exceeding 40
°
C, caution should be taken as the rated inverter current should be reduced.
Parameters referred to
Pr. 156 Stall prevention operation selection
Содержание FR-E710W-0.1K
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Страница 335: ...335 APPENDIX This chapter provides the APPENDIX of this product Always read the instructions before using the equipment ...
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