Mitsubishi Electric 700 Series, Instruction Manual

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52
Inverter-driven 400V class motor
3.4 Inverter-driven 400V class motor
In the PWM type inverter, a surge voltage attributable to wiring constants is generated at the motor terminals.
Especially for a 400V class motor, the surge voltage may deteriorate the insulation. When the 400V class motor is
driven by the inverter, consider the following measures:
z
Measures
It is recommended to take either of the following measures:
(1) Rectifying the motor insulation and limiting the PWM carrier frequency according to the wiring length
For the 400V class motor, use an insulation-enhanced motor.
Specifically,
1)Specify the "400V class inverter-driven insulation-enhanced motor".
2)For the dedicated motor such as the constant-torque motor and low-vibration motor, use the "inverter-driven,
dedicated motor".
3)Set Pr. 72 PWM frequency selection as indicated below according to the wiring length
(2) Suppressing the surge voltage on the inverter side
Connect the surge voltage suppression filter (FR-ASF-H) to the FR-F720-02330 (FR-F740-01160) or less and the
sine wave filter (MT-BSL/BSC) to the FR-F720-03160 (FR-F740-01800) or more on the inverter output side.
Wiring Length
50m or less 50m to 100m exceeding 100m
Pr. 72 PWM frequency selection 15(14.5kHz) or less 9(9kHz) or less 4(4kHz) or less
CAUTION
· For details of Pr. 72 PWM frequency selection , refer to page 169 . (When using an optional sine wave filter (MT-BSL/BSC) for the or
more, set "25" in Pr.72 (2.5kHz).)
· For explanation of surge voltage suppression filter (FR-ASF-H) and sine wave filter (MT-BSL/BSC), refer to the manual of each
option.