Mitsubishi Electric FR-E740 SC EC Series User Manual

Parameter Motor noise, EMI measures, mechanical resonance
FR-E700SC EC 6 - 173
6.15 Motor noise, EMI measures, mechanical resonance
6.15.1 PWM carrier frequency and soft-PWM control (Pr. 72, Pr. 240)
You can change the motor sound.
The above parameters can be set when Pr. 160 "User group read selection" = 0.

The above parameters allow its setting to be changed during operation in any operation mode
even if "0" (initial value) is set in Pr. 77 "Parameter write selection".
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 reducing noise or leakage current generated from the inverter.
Soft-PWM control (Pr. 240)
Soft-PWM control is a control system that changes the motor noise from a metallic tone into an un-
offending complex tone.
Purpose Parameters that must be set
Refer to
Section
Reduction of the motor noise
Measures against EMI and leakage cur-
rents
Carrier frequency and Soft-PWM selection Pr. 72, Pr. 240 6.15.1
Reduce mechanical resonance Speed smoothing control Pr. 653 6.15.2
Pr. No. Name Initial Value Setting Range Description Parameters referred to
Refer to
Section
72
PWM frequency
selection

1
0–15
(integral value)
PWM carrier frequency can be changed. The
setting displayed is in [kHz]. The settings indi-
cate the following frequencies:
0.......................0.7kHz
Settings between 1–14 correspond directly to
the frequency values.
15...................14.5kHz
156 Stall prevention
operation selection
6.3.5
240
Soft-PWM operation
selection

1
0 Soft-PWM is invalid
1 When Pr. 72 = 0 to 5, Soft-PWM is valid.
NOTES
Decreasing the PWM carrier frequency reduces inverter-generated noise and leakage current, but
increases motor noise.
When PWM carrier frequency is set to 1kHz or less (Pr. 72 ≤ 1), fast response current limit may func-
tion 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 preven-
tion operation selection".
When setting 2kHz or more in Pr. 72 to perform operation in the place where the ambient temper-
ature exceeding 40°C, caution should be taken as the rated inverter current should be reduced.
(Refer to appendix A-1.)

Mitsubishi Electric FR-E740 SC EC Series Specifications

General

Brand	Mitsubishi Electric
Model	FR-E740 SC EC Series
Category	Inverter
Language	English