Toshiba VF-S9 manual Inverters, Protecting inverters from overcurrent, Inverter capacity

E6580757

		ured in some other way, the overcurrent trip may be activated because of the locked rotor current when
		the brake goes into operation. Circuit configuration 2 uses low-speed signal RY to turn on and off the
		brake. Turning the brake on and off with a low-speed signal may be better in such applications as ele-
		vators. Please confer with us before designing the system.
	1.4.2	Inverters
1	Protecting inverters from overcurrent

The inverter has an overcurrent protection function. However because the programmed current level is set to the inverter's maximum applicable motor, if the motor is one of small capacity and it is in opera- tion, the overcurrent level and the electronic thermal protection must be readjusted. If adjustment is necessary, see 5-14 in Chapter 5, and make adjustments as directed.

Inverter capacity

Do not operate a large capacity motor with a small capacity (kVA) inverter even with light loads. Current ripple will raise the output peak current making it easier to set off the overcurrent trip.

Power factor improving capacitors

Power factor improving capacitors cannot be installed on the output side of the inverter. When a motor is run that has a power factor improving capacitor attached to it, remove the capacitors. This can cause inverter malfunction trips and capacitor destruction.

Inverter

Remove the power factor improving capacitor and surge absorber

Power factor improving capacitor

Operating at other than rated voltage

Connections to voltages other than the rated voltage described in the rating label cannot be made. If a connection must be made to a power supply other than one with rated voltage, use a transformer to raise or lower the voltage to the rated voltage.

A-12