2-3 Wiring „ Wiring the Main Circuit Terminals (Input Side) Installing a Molded-case Circuit Breaker (MCCB) •Always connect the Inverter and power supply via a molded-case circuit breaker (MCCB) to protect the Inverter from damage that may result from short-circuiting. •Always connect the power input terminals (R/L1, S/L2, and T/L3) and power supply via an MCCB, according to the Inverter capacity. •Install one MCCB per Inverter. •Choose an appropriate MCCB capacity according to the fuse size on page 2-15. •When choosing an MCCB's time characteristics, be sure to consider the Inverter's overload protection (1 minute at 150% of the rated output current).
•By programming the sequence as illustrated below, you can turn off the power via the relay outputs (MA, MB, and MC) for the 3G3MX Series. 2 Design Molded case circuit-breaker (MCCB) MC X1 R/L1 (L1) Inverter 3G3MX S/L2 (L2) T/L3 (N/L3) Power supply X1 X2 X2 MA MC (30 V DC, 50 mA max.) OFF ON X1 DC (24 V) relay * Terminal symbols for 3G3MX-AE ††† are indicated in parentheses ( ). Installing a Ground Fault Interrupter •The Inverter's output uses high-speed switching, and so generates high-frequency current leakage. (Generally, if the power cable is 1 m, the leakage current is approx. 100 mA per Inverter, and approx.
5 mA is added per additional meter.) •At the power supply input part, install a special-purpose ground fault interrupter for Inverters that exclude high-frequency leakage current and detect only the leakage current within a frequency range that is hazardous to humans. (Choose a ground fault interrupter with a sensitivity current of at least 10 mA per Inverter.) •Alternatively, use a general ground fault interrupter with a sensitivity current of 200 mA or more per Inverter, and with an operating time of 0.1 s or more. Installing a Magnetic Contactor (MC) •If the power supply of the main circuit is shut off due to sequencing, a magnetic contactor (MC) can be used.
(When forcibly stopping the load with an MC on the primary side of the main circuit, however, the regenerative braking does not work and the load coasts to a stop (free run).) •Frequently opening and closing the magnetic contactor (MC) to start and stop a load may cause the Inverter to break down. To extend the life of the Inverter's internal electrolytic capacitor, limit the frequency to no more than once every 30 minutes. Connection Sequence to the Terminal Block •Input power supply can be connected to any terminal because the phase sequence of the input power supply is irrelevant to that of the terminal block (R/L1, S/L2, and T/L3). 2-18