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Installing a Moulded-case Circuit Breaker
When connecting the power input terminals (R/L1, S/L2, and T/L3) to the power supply using a moulded-case
circuit breaker (MCCB) observe that the circuit breaker is suitable for the Inverter.
• Choose an MCCB with a capacity of 1.5 to 2 times of the inverter's rated current.
• For the MCCB's time characteristics, be sure to consider the inverter's overload protection (one minute at
150% of the rated output current).
Installing an Earth Leakage Breaker
Inverter outputs use high-speed switching, so high-frequency leakage current is generated. If an earth leakage
breaker should be used, select one that detects only the leakage current which is in the frequency range that is
hazardous to humans but not high-frequency leakage currents.
• For a special-purpose earth leakage breaker for Inverters, choose one with a sensitivity amperage of at
least 30 mA per Inverter.
• When using a general earth leakage breaker, choose one with a sensitivity amperage of 200 mA or more
per Inverter and with an operating time of 0.1 s or more.
Installing a Magnetic Contactor
If the power supply for the main circuit is to be shut off by a control circuit, a magnetic contactor can be used.
The following things should be considered:
• The Inverter can be started and stopped by opening and closing the magnetic contactor on the primary side.
Frequently opening and closing the magnetic contactor, however, may cause the Inverter to break down.
Do not exceed one power upper hour.
• When the Inverter is operated with the Digital Operator, automatic operation cannot be performed after
recovery from a power interruption.
Connecting Input Power Supply to the Terminal Block
Input power supply can be connected to any terminal R, S or T on the terminal block; the phase sequence of
input power supply is irrelevant to the output phase sequence.
Installing an AC Reactor
If the Inverter is connected to a large-capacity power transformer (600 kW or more) or a phase advancing
capacitor is switched, an excessive peak current may flow through the input power circuit, causing the inverter
unit to break down.
To prevent this, install an optional AC Reactor on the input side of the Inverter or a DC reactor to the DC reac-
tor connection terminals.
This also improves the power factor on the power supply side.
Installing a Surge Absorber
Always use a surge absorber or diode for inductive loads near the Inverter. These inductive loads include mag-
netic contactors, electromagnetic relays, solenoid valves, solenoids, and magnetic brakes.
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