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2 Design
High-function General-purpose Inverter 3G3RX-V1 User’s Manual (I578-E1)
2-3 Wiring
2
2-3-4 Wiring for Main Circuit Terminals
Installing earth leakage breaker
When selecting the earth leakage breaker to use between the power supply and the main power
supply input terminals (R/L1, S/L2, T/L3), consider the following two points.
High-frequency leakage current from inverter
The inverter produces a high-frequency leakage current due to its high-speed output switching.
In general, a leakage current of approximately 100 mA will flow for the power cable length of 1 m per
inverter. Moreover, an additional leakage current of approximately 5 mA will flow with the increasing
length by 1 m.
Therefore, an earth leakage breaker to use in the power input section must be dedicated for the
inverter, which removes high-frequency leakage current and detects only the leakage current in a
frequency range that is dangerous to the human body.
• Select a special earth leakage breaker for the inverter with a sensitivity current rating of 10 mA or
higher per inverter.
• If you use a general earth leakage breaker (which detects high-frequency leakage current), select
one with a sensitivity current rating of 200 mA or higher per inverter and an operation time of 0.1 s
or longer.
Leakage current from EMC noise filter
The EMC noise filter is designed to comply with European CE standards.
Specifically, it is designed to meet the neutral-point grounding requirement of the European power
supply specifications.
Therefore, using the EMC noise filter with the phase S grounding causes an increase of leakage
current.
For use with the phase S grounding, it is recommended to use the Input Noise Filter (Model:
3G3AX-NFI).
• Check the maximum leakage current value in the standard built-in EMC filter specifications for
3G3RX Series.
• Check also the maximum leakage current value in the optional external EMC noise filter
specifications.
Installing magnetic contactor
To shut off the main circuit power supply with a sequence, you can use a magnetic contactor (MC)
on the inverter side closer than a molded case circuit-breaker (MCCB).
However, do not run or stop the inverter by turning ON/OFF a magnetic contactor.
Use the RUN command signal (FW/RV) via the control circuit terminal of the inverter.
• Construct a sequence that turns OFF the power supply via the alarm output signal of the inverter.
• To use one or more braking resistors/regenerative braking units, construct a sequence that turns
OFF a magnetic contactor via a thermal relay contact in each unit.
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