Справочник Пользователя для Mitsubishi Electronics A800
Countermeasures against deterioration of the 400 V class motor insulation
72
NOTE
• Before wiring or inspection for a PM motor, confirm that the PM motor is stopped. In an application, such as fan and blower,
where the motor is driven by the load, a low-voltage manual contactor must be connected at the inverter's output side, and
wiring and inspection must be performed while the contactor is open. Otherwise you may get an electric shock.
wiring and inspection must be performed while the contactor is open. Otherwise you may get an electric shock.
• Do not open or close the contactor while the inverter is running (outputting).
3.5
Countermeasures against deterioration of
the 400 V class motor insulation
In the PWM type inverter, a surge voltage attributable to wiring constants is generated at the motor terminals. Especially in a
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:
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)
It is recommended to take one of the following countermeasures:
(With induction motor)
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
For the 400 V class motor, use an insulation-enhanced motor.
Specifically,
- 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
Specifically,
- 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".
- Set Pr.72 PWM frequency selection as indicated below according to the wiring length.
• Suppressing the surge voltage on the inverter side
- If the motor capacity is 280 kW or lower, connect the sine wave filter (MT-BSL/BSC) to the output side.
(With PM motor)
• When the wiring length exceeds 50 m, set "9" (6 kHz) or less in Pr.72 PWM frequency selection.
• When the wiring length exceeds 50 m, set "9" (6 kHz) or less in Pr.72 PWM frequency selection.
NOTE
• When using the optional sine wave filter (MT-BSL/BSC), set Pr.72="25" (2.5 kHz).
• For the details of the sine wave filter (MT-BSL/BSC), refer to the Instruction Manual of each option.
• A sine wave filter (MT-BSL/BSC) can be used under V/F control. Do not use the filters under different control methods.
• The carrier frequency is limited during PM sensorless vector control. (Refer to the FR-A800 Instruction Manual (Detailed))
• For the details of the sine wave filter (MT-BSL/BSC), refer to the Instruction Manual of each option.
• A sine wave filter (MT-BSL/BSC) can be used under V/F control. Do not use the filters under different control methods.
• The carrier frequency is limited during PM sensorless vector control. (Refer to the FR-A800 Instruction Manual (Detailed))
Wiring length
100 m or shorter
Longer than 100 m
Pr.72 PWM frequency selection
6 (6 kHz) or lower
4 (4 kHz) or lower