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Chapter 2 MOUNTING AND WIRING OF THE INVERTER
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
generated 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).)
Chapter 5 FUNCTION CODES
5.1 Function Code Tables
In the ROM version 0800 or later, the factory default of function code H27 (Thermistor for motor,
Level) is changed from 0.16 to 1.6.
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