1-4
Storage environment
The storage environment in which the inverter is stored after purchase is different from the operation environment.
For details, refer to the EQ7 DRIVE User's Manual, Chapter 2.
Wiring precautions
(1) Route the wiring of the control circuit terminals as far from the wiring of the main circuit as possible. Otherwise
electric noise may cause malfunctions.
(2) Place the control circuit wires inside the inverter to keep them away from the live parts of the main circuit (such as
the terminal block of the main circuit).
(3) If more than one motor is to be connected to a single inverter, the wiring length should be the sum of the length of
the wires to the motors.
(4) Drive output terminals (U, V, W)
1) Connect these terminals to a 3-phase motor in the correct phase sequence. If the direction of motor rotation is
incorrect, exchange any two of the U, V, and W phases.
2) Do not connect a power factor correction capacitor or surge suppressor to the inverter output.
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:
Inverter 7.5 HP and larger
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)*
Inverter 5 HP and smaller
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 (100 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".)
• For the vector control mode, wiring length is 328 ft (100 m) or less.
(5)
When an output circuit filter is inserted in the secondary circuit or the wiring between the inverter and the
motor is long, a voltage loss occurs due to reactance of the filter or wiring so that the insufficient voltage may cause
output current oscillation or a lack of motor output torque. To avoid it, select the constant torque load by setting the
function code F37 (Load Selection/Auto Torque Boost/Auto Energy Saving Operation 1) to "1" and keep the inverter
output voltage at a higher level by configuring H50/H52 (Non-linear V/f Pattern, Frequency) and H51/H53 (Non-linear
V/f Pattern, Voltage).