15
Peripheral Equipment
Caution in Selecting Peripheral Equipment
Wiring and connection
1. Be sure to connect the power supply to RST (input terminals) and the motor to U, V, W (output terminals).
2. Be sure to connect the grounding terminal. (
mark)
Inverters generate high frequency, increasing leakage current. Be sure to ground the inverter and motor.
Wiring
between
inverter and
motor
Electromagnetic
contactor
When using an electromagnetic contactor between the inverter and motor, do not turn the contactor ON or OFF during inverter
operation.
Thermal relay
Install a thermal relay that matches the motor in the following cases:
*Install a thermal relay for each motor when operating more than one motor with one inverter.
*Set the current of the thermal relay at the rated motor current x 1.1. When the wiring length is long (more than 10 m), the
thermal relay may be activated too quickly. Install an AC reactor or current sensor on the output side.
*When motors are to be operated with the rated current exceeding the adjustable level of the built-in electronic thermal relay.
Earth leakage breaker
Install an earth leakage breaker on the input side for protection of the inverter wiring and operators.
Conventional earth leakage breakers may malfunction because of high harmonics from the inverter; therefore use an earth
leakage breaker that is applicable to the inverter. The leakage current differs according to the cable length. Refer to p.14.
Wiring distance
The wiring distance between the inverter and operation panel should be less than 30m. If it exceeds 30m, use a current/voltage
converter, etc. Use shielded cable for wiring.
When the wiring distance between the motor and inverter is long, the leakage current from high harmonics may cause the
protective function of the inverter and peripheral equipment to be activated.
The situation will be improved by an AC reactor installed on the output side of the inverter.
Select appropriate cable to prevent voltage drop. (Large voltage drop lowers the torque.)
Phase-advanced capacitor
Do not use a phase-advanced capacitor.
When a power factor improving capacitor is connected between the inverter and motor, the capacitor may be heated or broken
by the higher harmonics in the inverter output.
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