Chapter 2 Installation and Wiring
15
2.4.2 Main Circuit Wiring Operation
When the motor is running, please make sure if it is in positive rotation while the motor
receives positive rotation command. If the motor is in reverse rotation, the rotation
direction of the motor can be changed by exchanging any two wires of output terminals
(U, V, and W) of the inverter. The rotation direction can also be changed by modifying
the function code P2.33 to change the phase sequence of the motor.
Do not mistakenly connect the input power cable to the output terminal; otherwise the
components in the inverter will be damaged. Output terminals are prohibited to be
grounded. The lines should not be collided with the enclosure, or short connected;
otherwise the inverter will be damaged. Be sure Earth terminal “PE” is connected to
earth. The earthing resistance of 380V-class should be below 10Ω. Be sure the earthing
not be shared with electric welding machines or other high-current electrical equipments.
Use ground wiring as mentioned in “Appendix 3 Main Circuit Output Cable Selection”
and keep the length as short as possible.
When two or more inverters are used at the same time,
do not loop the wires. The right
and wrong earthling connection methods are shown as Figure 2-9.
Inverter
InverterRight
Inverter
InverterInverter
Wrong
Inverter
Fig. 2-9 Earthing Connection Method
Attention: The neutral point of motor using Y connection can’t be connected to
earth.
Since the inverter output PWM wave, if a capacitance for improving power factor or a
lightning varistor is installed on the output side, which would cause tripping or damage
to parts, be sure to remove it.
If a contactor or other on-off part is needed to be installed between the output and the
motor, be sure the on-off operation is done when the inverter has no output, otherwise the
inverter would be damaged.
Countermeasures to conduction interference: To inhibit conduction interference of the
output, besides installing noise filter and using shielded motor cables, leading all the
output cables to earthing metal tube is also a method. Make the distance between the
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