Operating At Other Than Rated Voltage; Selective Circuit Breaking When Two Or More Inverters Are Used On The Same Power Line; If Power Supply Distortion Is Not Negligible; If Multiple Inverters Are Connected With Common Dc Bus Link - Toshiba TOSVERT VF-AS3 Instruction Manual

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■ 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.
■ Selective circuit breaking when two or more inverters are used on the same
power line
There is no fuse in the inverter's power circuit. Thus, as the diagram below shows, when more than
one inverter is used on the same power line, you must select interrupting characteristics so that only
MCCB (MCCB2 to MCCBn+1 in the diagram) install in each inverter will trip and the common MCCB
(MCCB1 in the diagram) will not trip when a short occurs in one inverter.
When you cannot select the proper characteristics, install a circuit interrupting fuse on the second-
ary side of MCCB2 to MCCBn+1.
9
* MCCB : Molded-case circuit breaker

■ If power supply distortion is not negligible

If the power supply distortion is not negligible because the inverter shares a power distribution line
with other systems causing distorted waves, such as systems with thyristors or large-capacity invert-
ers, install an input reactor to improve the input power factor, to reduce higher harmonics, or to sup-
press external surges.
For details, refer to [10. 3. 1].

■ If multiple inverters are connected with common DC bus link

When inverters are fed by AC power supply and connected with common DC bus link, step-out is
generated and ground fault trip may occur. In this case, set <F636: Ground fault trip> = "0: Dis-
abled".
2. Installation and wiring
U/T1
Inverter
V/T2
W/T3
Power factor correction capacitor
MCCB1 MCCB2
MCCB3
MCCBn 1
Selective circuit breaking of inverters
M
Remove power factor correction
capacitors and surge absorber.
(Circuit breaking fuse)
Inverter 1
Inverter 2
Inverter n
2-56
E6582062