Mitsubishi Electric FR-A800, Instruction Manual

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Main circuit terminals Installation and wiring
2 - 32
Total wiring length
●
With induction motor
Connect one or more induction motors within the total wiring length shown in the following table.
(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 measures.
– Use a "400 V class inverter-driven insulation-enhanced motor" and set Pr. 72 "PWM frequency
selection" according to the wiring length.
– For the FR-A840-01800(55K) or lower, connect a surge voltage suppression filter (FR-ASF-H/FR-
BMF-H) at the output side of the inverter. For the FR-A840-02160(75K) or higher, connect a sine
wave filter (MT-BSL/BSC) at the output side of the inverter.
●
With PM motor
The wiring length should be 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 sensor-
less vector control, set "9" (6 kHz)
or less in Pr. 72 "PWM frequency selection".
Pr. 72 setting
(carrier frequency)
FR-A820-00046(0.4K)
FR-A840-00023(0.4K) FR-A820-00077(0.75K)
FR-A840-00038(0.75K)
FR-A820-00105(1.5K)
or higher
FR-A840-00052(1.5K)
or higher
2 (2 kHz) or lower 300 m 500 m 500 m
3 (3 kHz) or higher 200 m 300 m 500 m
Tab. 2-11: Total wiring length
I002368E
Fig. 2-20: Total wiring length (FR-A820-00105(1.5K) or higher, FR-A840-00052(1.5K) or higher)
Wiring length
50 m 50 m–100 m 100 m
Pr. 72 setting 15 (14.5 kHz) 9 (9 kHz) 4 (4 kHz)
Tab. 2-12: PWM frequency
≤
500 m
300 m
300 m
300 m + 300 m = 600 m