Mitsubishi Electric FR-A720-0.4K Instruction Manual page 33

Main circuit terminal specifications
(3) Total wiring length
The overall wiring length for connection of a single motor or multiple motors should be within the value in the table below.
(The wiring length should be 100m maximum for vector control.)
Pr. 72 setting (carrier frequency)
2 (2kHz) or lower
3 (3kHz) or higher
Total wiring length (1.5K or higher)
When driving a 400V class motor by the inverter, surge voltages attributable to the wiring constants may occur at the
motor terminals, deteriorating the insulation of the motor.
Refer to page 62 for measures against deteriorated insulation.
CAUTION
· Especially for long-distance wiring, the inverter may be affected by a charging current caused by the stray capacitances of the
wiring, leading to a malfunction of the overcurrent protective function or fast response current limit function or a malfunction or fault
of the equipment connected on the inverter output side. If fast response current limit function malfunctions, disable this function.
(For Pr. 156 Stall prevention operation selection, refer to page 152 .)
· For details of Pr. 72 PWM frequency selection , refer to page 284.
(4) Cable size of the control circuit power supply (terminal R1/L11, S1/L21)
· Terminal screw size: M4
2
· Cable size: 0.75mm
· Tightening torque: 1.5N·m
22
500m or less
2
to 2mm
0.4K 0.75K
300m 500m
200m 300m
300m
300m
300m + 300m = 600m
1.5K or higher
500m
500m