3.5 Countermeasures against deterioration of the 400 V class motor insulation 1 In the PWM type inverter, a surge voltage attributable to wiring constants is generated at the motor terminals. Especially in a 2 400 V class motor, the surge voltage may deteriorate the insulation. When the 400 V class motor is driven by the inverter, consider the following countermeasures: Countermeasures (with induction motor) 3 It is recommended to take one of the following countermeasures: Rectifying the motor insulation and limiting the PWM carrier frequency according to the wiring length 5 For the 400 V class motor, use an insulation-enhanced motor.
Specifically, 5 • Order a "400 V class inverter-driven insulation-enhanced motor". • For the dedicated motor such as the constant-torque motor and low-vibration motor, use an "inverter-driven dedicated motor". 6 • Set Pr.72 PWM frequency selection as indicated below according to the wiring length. 7 Suppressing the surge voltage on the inverter side • Connect the surge voltage suppression filter (FR-ASF-H/FR-BMF-H) to the output side. 8 • For the details of the surge voltage suppression filter (FR-ASF-H/FR-BMF-H), refer to the Instruction Manual of each option. 9 10 59 3.
PRECAUTIONS FOR USE OF THE INVERTER 3.5 Countermeasures against deterioration of the 400 V class motor insulation Wiring length Shorter than 50 m 50 to 100 m Pr.72 PWM frequency selection Any setting 8 (8 kHz) or lower NOTE