Mitsubishi Electric FR-A720-0.4K Instruction Manual page 23

Wiring
(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.
Take the following measures (1) or (2) in this case.
(1) Use a "400V class inverter-driven insulation-enhanced motor" and set frequency in Pr. 72 PWM frequency selection
according to wiring length
Carrier frequency
(2) Connect the surge voltage suppression filter (FR-ASF-H/FR-BMF-H) to the 55K or lower and the sine wave filter (MT-
BSL/BSC) to the 75K or higher on the inverter output side.
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 Chapter 4 of
· For details of Pr. 72 PWM frequency selection , refer to Chapter 4 of
filter (MT-BSL/BSC) for the 75K or higher, set "25" (2.5kHz) in Pr. 72.)
For explanation of surge voltage suppression filter (FR-ASF-H/FR-BMF-H) and sine wave filter (MT-BSL/BSC), refer to the
manual of each option.
· The surge voltage suppression filter (FR-ASF-H/FR-BMF-H) can be used under V/F control and under Advanced magnetic flux
vector control. The sine wave filter (MT-BSL/BSC) can be used under V/F control.
(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
16
500m or less
50m or less
14.5kHz or less
2
to 2mm
0.4K 0.75K
300m 500m
200m 300m
300m
300m
300m + 300m = 600m
Wiring Length
50m to 100m
9kHz or less
the Instruction Manual (Applied).)
the Instruction Manual (Applied). (When using an option sine wave
1.5K or higher
500m
500m
exceeding 100m
4kHz or less