Mitsubishi Electric FR-D720S SC EC Instruction Manual page 44

Main circuit connection
Cables and wiring length
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 tables indicate a selection example for the wiring length of 20m.
200V class (when input power supply is 220V)
Terminal
Applicable Inverter
Screw
Type
Size
FR-D720S-008SC to
M3,5
042SC
FR-D720S-070SC M4
FR-D720S-100SC M4
Tab. 3-5: Cable size
400V class (when input power supply is 440V)
Terminal
Applicable Inverter
Screw
Type
Size
FR-D740-012SC to
M4
080SC
FR-D740-120SC M4
FR-D740-160SC M4
Tab. 3-6: Cable size
The recommended cable size is that of the HIV cable (600V class 2 vinyl-insulated cable)
with continuous maximum permissible temperature of 75°C. Assumes that the ambient
temperature is 50°C or less and the wiring distance is 20m or less.
The recommended cable size is that of the THHW cable with continuous maximum
permissible temperature of 75°C. Assumes that the ambient temperature is 40°C or less
and the wiring distance is 20m or less.
(Selection example for use mainly in the United States.)
The recommended cable size is that of the PVC cable with continuous maximum permissible
temperature of 70°C. Assumes that the ambient temperature is 40°C or less and the wiring
distance is 20m or less.
(Selection example for use mainly in Europe.)
The terminal screw size indicates the terminal size for R/L1, S/L2, T/L3, U, V, W, PR, P/+,
N/–, P1 and a screw for earthing. (For single-phase power input, the terminal screw size
indicates the size of terminal screw for L1, N, U, V, W, PR, +, – and P1 and a screw for
earthing (grounding).)
The line voltage drop can be calculated by the following expression:
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.
3 - 8
Crimping
Tighten-
Terminal
ing
Torque
L1, N,
[Nm]
U, V, W
P1, +
1,2 2-3,5 2-3,5
1,5 2-4 2-4
1,5 5,5-4 2-4
Crimping
Tighten-
Terminal
ing
Torque
L1, L2,
[Nm]
L3, P1, U, V, W
P/+
1,5 2-4 2-4
1,5 5,5-4 2-4
1,5 5,5-4 5,5-4
× wire resistance [mΩ/m ]
3
---------------------------------------------------------------------------------------------------------------------------------------------------------------------- -
HIV etc. [mm²]
Earth
L1, N, L1, N,
U, V, W Cable
P1, + P1, +
Gauge
2 2 2
2 2 2
3,5 2 3,5
HIV etc. [mm²]
L1, L2, Earth L1, L2,
L3, P1, U, V, W Cable L3, P1,
P/+ Gauge
2 2 2
3,5 2 3,5
3,5 3,5 3,5
×
wiring distance [m]
1000
Cable Size
AWG PVC [mm²]
L1, N,
U, V, W U, V, W
P1, +
14 14 2,5 2,5
14 14 2,5 2,5
12 14 4 2,5
Cable Size
AWG PVC [mm²]
L1, L2,
U, V, W L3, P1, U, V, W
P/+ P/+
14 14 2,5 2,5
12 14 4 2,5
12 12 4 4
×
current [A]
Wiring
Earth
Cable
Gauge
2,5
2,5
4
Earth
Cable
Gauge
2,5
4
4