Mitsubishi Electric FR-A800 Series Instruction Manual page 67

NOTE
• Tighten the terminal screw to the specified torque.
A screw that has been tightened too loosely can cause a short circuit or malfunction.
A screw that has been tightened too tightly can cause a short circuit or malfunction due to the unit breakage.
• Use crimp terminals with insulation sleeves to wire the power supply and motor.
 Total wiring length
 With induction motor
Connect one or more general-purpose motors within the total wiring length shown in the following table. (The wiring length
should be 100 m or shorter under Vector control.)
Pr.72 setting
(carrier frequency)
2 (2 kHz) or lower
3 (3 kHz) or higher
Total wiring length (FR-A820-00105(1.5K) or higher, FR-A840-00052(1.5K) or higher)
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.
Wiring length 50 m or
shorter
15 (14.5 kHz) or lower
• 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
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.
NOTE
• Especially for long-distance wiring, the inverter may be affected by a charging current caused by stray capacitance 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. (Refer to Pr.156 Stall prevention operation selection
on page
• A surge voltage suppression filter (FR-ASF-H/FR-BMF-H) can be used under V/F control and Advanced magnetic flux vector
control.
A sine wave filter (MT-BSL/BSC) can be used under V/F control. Do not use the filters under different control methods.
• For details on Pr.72 PWM frequency selection, refer to
• Refer to
• The carrier frequency is limited during PM sensorless vector control. (Refer to
66
2. INSTALLATION AND WIRING
2.5 Main circuit terminals
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FR-A820-00046(0.4K) FR-A820-00077(0.75K)
FR-A840-00023(0.4K) FR-A840-00038(0.75K)
300 m 500 m
200 m 300 m
500 m or less
Wiring length 50 to 100 m
9 (9 kHz) or lower
431.)
page 130 to drive a 400 V class motor by an inverter.
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FR-A820-00105(1.5K) or higher
FR-A840-00052(1.5K) or higher
500 m
500 m
300 m
300 m
300 m + 300 m = 600 m
Wiring length longer
than 100 m
4 (4 kHz) or lower
page 356.
page 356.)