Toshiba VF-AS1 instruction manual Inverters

!	E6581301!
In circuit configuration 1, the brake is turned on and off through MC2 and MC3. If the circuit is configured 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 OUT1 to turn on and off the brake. Turning the brake on and off with a
low-speed detection (OUT1 function) may be better in such applications as elevators. Please confer with your
Toshiba distributor before designing the system.
Measures to protect motors against surge voltages
In a system in which a 400V-class inverter is used to control the operation of a motor, very high surge voltages may
be produced. When applied to the motor coils repeatedly for a long time this can cause deterioration of their
insulation, depending on the wire length, wire routing and types of wires used. Here are some examples of		1
measures against surge voltages.

(1)Lower the inverter’s carrier frequency.

(2)Set the parameter ￿￿￿￿￿(Carrier frequency control mode selection) to ￿ or ￿.

(3)Use motors with a high dielectric strength.

(4)Insert an reactor or a surge voltage suppression filter between the inverter and the motor.

1.4.2Inverters

Protecting inverters from overcurrent

The inverter has an overcurrent protection function. The programmed current level is set to the inverter's maximum applicable motor. If the motor used has a small capacity, the stall prevention level, overcurrent level and the motor electronic thermal protection must be readjusted. If adjustment is necessary, refer to Section 5.14, 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 correction capacitor

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

U

Inverter

V

W

IM

Remove the power factor correction capacitor and surge absorber

Power factor correction

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.

Circuit interrupting when two or more inverters are used on the same power line.

!	! (Circuit interrupting fuse)
MCCB1	MCCB2
	INV1
	MCCB3
	INV2
	MCCBn
	INVn

Breaking of selected inverter

A-19