GE C11, AF-300 manual Harmonic component, Noise, Leakage current, Others

2-4 Others

2-4-1 Harmonic component

A harmonic component which may influence the phase-advance capacitor and generator is included in the drive input current. If necessary , connect a power-factor correcting DC reactor (DCR) (option) for the drive.

2-4-2 Noise

When noise generated from the drive may affect peripheral equipment, and noise generated from pe- ripheral equipment may malfunction the drive, the following basic countermeasures should be taken.

1.When noise affects other devices via power and ground wires

·Separate the ground of the drive and that of the affected device.

·Connect a noise filter to the drive power wire.

·Use an isolation transformer to separate the power supply of the drive and that of the affected device.

2)When another device is affected by induction or radiation

·Separate the main circuit wiring of the drive from the control wiring and wiring of the affected de- vice.

·Encase the drive main circuit wiring in a metal tube and ground the metal tube near the drive.

·Encase the drive in a metal rack and ground the rack.

·Connect a noise filter to the drive power wire.

3)When noise generated from peripheral equipment affects the drive

·Use twisted or twisted-pair shielded wires for the drive control wiring. Ground the shields.

·Connect a surge absorber in parallel to the coil of the magnetic contactor and solenoid .

·If the power supply includes much distortion of the waveform or surge, connect an impedance matching AC reactor for coordination of power supply.

2-4-3 Leakage current

Leakage current flows through the drive I-O wiring and motor stray capacitance when the drive transistor is turned on and off. Table 2-3-3 lists the countermeasures for the problems caused by the leakage current.

Table 2-3-3 Countermeasures for leakage current

	Problem	Countermeasures
1	Trip of earth leakage circuit breaker	Set the carrier frequency lower.
		Shorten the wiring between the drive and motor.
	on main power supply side
		Increase the ELCB/RCD sensitivity current.
		Replace the ELCB/RCD with an ELCB/RCD that is de-
		signed for high frequencies.
2	Trip of external thermal O/L relay	Set the carrier frequency lower.
		Increase the thermal O/L relay set value.
		Use the drive electronic thermal O/L relay.

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