Pwm Carrier Frequency (Pr. 72, Pr. 240) - Mitsubishi Electric FR-A520-0.4K Instruction Manual

4.2.29 PWM carrier frequency (Pr. 72, Pr. 240)

Pr. 72 "PWM frequency selection"
Pr. 240 "Soft-PWM setting"
You can change the motor tone.
• By parameter setting, you can set whether to exercise the 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 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 long wiring mode.)
Parameter Factory Setting Setting Range
72 2
240 1
<Setting>
• Refer to the following list and set the parameters:
Pr. 72 Setting
PWM carrier frequency can be changed.
0 to 15
The setting displayed is in [kHz]. Note that 0 indicates 0.7kHz and 15 indicates 14.5kHz.
Note: A decreased PWM carrier frequency will decrease noise and leakage currents from the inverter but
increase the motor sound. Therefore, perform the reduction techniques. (Refer to page 38.)
Pr. 240
Setting
Soft-PWM
0 Invalid
Valid
1
when Pr. 72="0 to 5"
10(Note) Invalid
11(Note) Valid
Note: 1. Output voltage at the rated frequency decreases by 5V maximum.
2. If you copied parameters to the previous version inverter (Pr. 240="10 or 11" is not available), set
Pr. 240 again.
3. Under vector control mode with the option (FR-A5AP), the long wiring mode is not activated even
if it is selected.
4. For the 400V class, use an inverter duty motor. (Using other motors may result in insulation
deterioration of motors due to surge voltage independently of the Pr. 240 setting.)
5. Values exceed 120Hz can not be written to Pr. 1 (Pr. 18) when Pr. 240="10 or 11". Similarly, "10
or 11" can not be written to Pr. 240 when the value set in Pr. 1 (Pr. 18) exceeds 120Hz.
0 to 15
15 : 14.5kHz
0, 1, 10, 11
Description
Description
Long wiring mode
Invalid
Invalid
Valid • When Pr. 72"PWM frequency
selection"="0 or 1", PWM carrier
frequency is 0.7kHz constant.
• When Pr. 72"PWM frequency
Valid
selection"="2 or more", PWM
carrier frequency is 2kHz constant.
106
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Remarks
0 : 0.7kHz
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Remarks
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PARAMETERS