Inverter-Driven 400V Class Motor - Mitsubishi Electric FR-F740 EC Instruction Manual

Electromagnetic compatibility (EMC)
3.8.5

Inverter-driven 400V class motor

In the PWM type inverter, a surge voltage attributable to wiring constants is generated at the mo-
tor terminals. Especially for a 400V class motor, the surge voltage may deteriorate the insula-
tion. When the 400V class motor is driven by the inverter, consider the following measures:
● 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.
– Specify the "400V class inverter-driven insulation-enhanced motor".
– For the dedicated motor such as the constant-torque motor and low-vibration motor, use
the "inverter-driven, dedicated motor".
– Set Pr. 72 "PWM frequency selection" as indicated below according to the wiring length.
Parameter 72
Tab. 3-17: Setting of Pr. 72 according to the wiring length
● Limiting the voltage rise speed of the frequency inverter output voltage (dU/dT):
If the motor requires a rise speed of 500V/µs or less you must install a filter in the output of
the inverter. Please contact your Mitsubishi dealer for more details.
NOTE For details of Pr. 72 "PWM frequency selection", refer to section 6.14.
3 - 54
≤ 50m
≤ 15 (14.5kHz)
Wiring length
50m to 100m
≤ 9 (9kHz)
Wiring
≥ 100m
≤ 4 (4kHz)