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Mitsubishi Electric FR-A700 Series Installation Manuallines page 13

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(3) Applicable cable size
Select the recommended cable size to ensure that a voltage drop will be 2% max.
If the wiring distance is long between the inverter and motor, a main circuit cable voltage drop will cause the motor
torque to decrease especially at the output of a low frequency.
The following table indicates a selection example for the wiring length of 20m.
690V class
Terminal
Applicable
Screw Size
Inverter Model
*2
FR-A770-355K-79
M12(M10)
FR-A770-560K-79
M12(M10)
*1
The recommended cable size is that of the cable (LMFC (heat resistant flexible cross-linked polyethylene insulated cable) etc.) with continuous
maximum permissible temperature of 90°C. Assumes that the surrounding air temperature is 50°Cor less and wiring is performed in an
enclosure.
*2
The terminal screw size indicates the terminal size for R/L1, S/L2, T/L3, U, V, W, PR, PX, P/+, N/-, P1, and a screw for earthing (grounding).
The line voltage drop can be calculated by the following formula:
3 × wire resistance[mΩ/m] × wiring distance[m] × current[A]
Line voltage drop [V]=
Use a larger diameter cable when the wiring distance is long or when it is desired to decrease the voltage drop (torque
reduction) in the low speed range.
CAUTION
· Tighten the terminal screw to the specified torque.
A screw that has been tighten too loosely can cause a short circuit or malfunction.
A screw that has been tighten too tightly can cause a short circuit or malfunction due to the unit breakage.
· Use crimping terminals with insulation sleeve to wire the power supply and motor.
(4) Total wiring length
Connect one or more motors within a total wiring length of 500m.
(The wiring length should be 100m maximum for vector control.)
When driving a 690V 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 measure in this case.
Use a "690V class inverter-driven insulation-enhanced motor"
(5) 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
Tightening
R/L1,
Torque
S/L2,
N·m
T/L3
46
200-12
46
150-12
2
to 2mm
Crimping Terminal
Earth
U, V, W P/+, P1
(Ground)
Cable
200-12
325-12
150-10
150-12
200-12
200-10
1000
WIRING
2
Cable Size (mm
)
R/L1,
S/L2,
U, V, W P/+, P1
T/L3
200
200
250
2150
2150
2200
*1
Earth
(Ground)
Cable
150
200
10

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This manual is also suitable for:

Fr-a700-560k-79Fr-a700-355k-79