‹ Input and Output Wiring in the Main Circuit This section describes wiring connections for the main circuit inputs and outputs. „ Wiring Main Circuit Inputs Observe the following precautions when wiring inputs for the main circuit power supply. Installing a Molded-Case Circuit Breaker Always connect the power input terminals (R, S, and T) and power supply via a molded-case circuit breaker (MCCB) suitable for the MxC. • Choose an MCCB with a capacity of 1.5 to 2 times larger than the rated current of the MxC. • The MCCB operation time should reflect the overload protection time of the MxC.
• If the same MCCB is to be used for more than one MxC or in other devices, set up a sequence so that the power supply will be turned off by a fault output, as shown in Fig 2.7 . Power supply MxC 25P5 to 2022: 3-phase, 200 to 220 VAC, 50/60 Hz 45P5 to 4022: 3-phase, 380 to 480 VAC, 50/60 Hz MC MCCB R/L1 S/L2 T/L3 MC MB off on MC Fault output (NC) MC * For 400 V class MxCs, connect a 400/200 V transformer. Fig 2.7 MCCB Installation Installing a Ground Fault Interrupter MxC outputs use high-speed switching, causing high-frequency leakage current to be generated.
A ground fault interrupter is therefore needed on the primary side of the MxC in order to detect any hazardous leakage current within the frequency, and to exclude that high-frequency leakage current. • When deciding to use a special-purpose ground fault interrupter for the MxC, choose a ground fault inter- rupter with a sensitivity amperage of at least 30 mA per MxC. • When using a general ground fault interrupter, choose a ground fault interrupter with a sensitivity amper- age of 200 mA or more per MxC and with an operating time of 0.1 s or more. 2 -10 SA