MITSUBISHI ELECTRIC FR-S520E - Manual (Page 117)

107
Operation selection function parameters
2
F
UNCT
IO
NS
2.10.2 PWM carrier frequency and long wiring mode (Pr. 70
, Pr. 72 )
• By parameter setting, you can set whether to exercise Soft-PWM control that
changes the motor tone or select with or without long wiring mode.
• Soft-PWM control is a control system that changes the motor noise from a metallic tone into an
unoffending complex tone.
• Surge voltage is suppressed regardless of wiring length in the long wiring mode. (When
operating the 400V motor with wiring length of 40m or longer, select the long wiring mode.)
Refer to (page 73).
You can change the motor sound.
Parameter Name
Factory
Setting
Setting
Range
Remarks
70 Soft-PWM setting 1 0, 1, 10, 11 Setting is enabled when
Pr. 30 = "1" 72 PWM frequency selection 1 0 to 15
Pr.70
Setting
Description
Soft-PWM Long wiring mode Remarks
0 Invalid Invalid 
1
Valid
(When Pr. 72 setting
= any of "0" to "5")
Invalid 
10 Invalid Valid
•When Pr. 72 "PWM frequency
selection" = 1 or more, the PWM
carrier frequency is constant at
1kHz. (When "0" is set, the PWM
carrier frequency is constant at
0.7kHz.)
11 Valid Valid
CAUTION
1.The output voltage at the rated frequency drops by a maximum of 5V.
2.For the 400V class, use an insulation-enhanced motor.
Refer to page 24 for an inverter-driven 400V class motor.
Pr.72 Setting Description
0 to 15
PWM carrier frequency can be changed.
The setting displayed is in [kHz].
Note that 0 indicates 0.7kHz and 15 indicates 14.5kHz.
REMARKS
•An increased PWM frequency will decrease the motor sound but increase noise and leakage
currents. Therefore, perform the reduction techniques. (Refer to page 18.)
•Metallic sound may be generated from the motor at sudden deceleration but it is not a fault.