Total wiring length
With induction motor
Connect one or more general-purpose motors within the total wiring length 500 m. (The wiring length should be 100 m or shorter
under Vector control.)
When driving a 400 V class motor by the inverter, surge voltages attributable to the wiring constants may occur at the motor
terminals, deteriorating the insulation of the motor. In this case, take one of the following measure.
• Use a "400 V class inverter-driven insulation-enhanced motor" and set Pr.72 PWM frequency selection according to the
Wiring length 100 m or shorter
6 (6 kHz) or lower
• If the motor capacity is 280 kW or lower, connect the sine wave filter (MT-BSL/BSC) to the output side.
With PM motor
Use the wiring length of 100 m or shorter when connecting a PM motor.
Use one PM motor for one inverter. Multiple PM motors cannot be connected to an inverter.
When the wiring length exceeds 50 m for a 400 V class motor driven by an inverter under PM sensorless vector control, set "9"
(6 kHz) or less in Pr.72 PWM frequency selection.
• Especially for long-distance wiring, the inverter may be affected by a charging current caused by stray capacitances of the
wiring, leading to an activation of the overcurrent protection, malfunction of the fast-response current limit operation, or even
to an inverter failure. It may also cause a malfunction or fault of the equipment connected ON the inverter output side. If the
fast-response current limit function malfunctions, disable the function. (For the details of Pr.156 Stall prevention operation
selection, refer to the FR-A800 Instruction Manual (Detailed).)
• A sine wave filter (MT-BSL/BSC) can be used under V/F control. Do not use the filters under different control methods.
• For the details of Pr.72 PWM frequency selection, refer to the Instruction Manual (Detailed).
• Refer to
• The carrier frequency is limited during PM sensorless vector control. (Refer to the Instruction Manual (Detailed).)
2. INSTALLATION AND WIRING
2.5 Main circuit terminals
Total wiring length
500 m or less
4 (4 kHz) or lower
to drive a 400 V class motor by an inverter.
300 m+300 m=600 m
Wiring length longer than 100 m