Table 2.6 Recommended Wire Sizes (Continued)
Recommended wire size (AWG ) *1
Main circuit
Main circuit power input
[L1/R, L2/S, L3/T]
[L1/L, L2/N]
Grounding [
G]
Power supply voltage
Nomi-
nal
applied
motor
(HP)
Inverter type
w/ DCR w/o DCR *2
Inverter
output
[U, V, W]
DCR
[P1, P (+)]
Braking
resistor
[P (+), DB]
Control
circuit
7.5
FRN0013C2S-4U
14/12
(13)
14/14
(13)
14/14
(13)
10
FRN0018C2S-4U
14/14
(13)
14/10
(11)
14/12
(13)
14/12
(13)
15
FRN0024C2S-4U
14/10
(11)
12 /8
(9)
14/10
(11)
12/10
(11)
Three-phase
400 V
20
FRN0030C2S-4U
12 /8
(9)
10/ 6
(7)
12/ 8
(9)
10 /6
(9)
14/14
(13)
20
16
DCR: DC reactor
*1 Use crimp terminals covered with an insulated sheath or insulating tube. Recommended wire sizes are
for HIV
/IV (PVC in the EU).
*2 Wire sizes are calculated on the basis of input RMS current under the condition that the power suppl
y
capacity and impedance are 500 kVA and 5%, respectively.
*3 Insert the DC reactor (DCR) in either of the primary power input lines. Refer to Chapter 10 for more
details.
2.3.5 Wiring for main circuit terminals and grounding terminals
Inverter output terminals, U, V, W and grounding terminal ( G)
1) Connect the three wires of the three-phase motor to terminals U, V, and W, aligning phases each other.
2) Connect the grounding wire of terminals U, V, and W to the grounding terminal (
G).
3) If the cable from the inverter to the motor is very long, a high-frequency current may be generated by stray
capacitance between the cables and result in an overcurrent trip of the inverter, an increase in leakage
current, or a reduction in current indication precision.
When a motor is driven by a PWM-type inverter, the motor terminals may be subject to surge voltage gen-
erated by inverter element switching. If the motor cable (with 460 V series motors, in particular) is particularly
long, surge voltage will deteriorate motor insulation. To prevent this, use the following guidelines:
Inverters of 7.5 HP or above
Motor Insulation Level 1000 V 1300 V 1600 V
460 VAC Input Voltage 66 ft (20 m) 328 ft (100 m) 1312 ft (400 m)*
230 VAC Input Voltage 1312 ft (400 m)* 1312 ft (400 m)* 1312 ft (400 m)*
Inverters of 5 HP or below
Motor Insulation Level 1000 V 1300 V 1600 V
460 VAC Input Voltage 66 ft (20 m) 165 ft (50 m) 165 ft (50 m)*
230 VAC Input Voltage 328 ft (400 m)* 328 ft (100 m)* 328 ft (100 m)*
* For this case the cable length is determined by secondary effects and not voltage spiking.
When a motor protective thermal O/L relay is inserted between the inverter and the motor, the
thermal O/L relay may malfunction (particularly in the 460 V series), even when the cable
length is 165 ft (50 m) or less. To correct, insert a filter or reduce the carrier frequency. (Use
function code F26 (Motor sound).)
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