The MPCB serves as the main power switch and provides overcurrent and short-circuit protection. The contactor controls the motor's power supply. When the selector switch is activated, the contactor coil is energized, closing the contactor and supplying power to the motor. So we CNC Electric just offers the full and comprehensive electrical solutions with various electrical appliances included. Welcome to be our distributors and agents for mutual benefit. More info about us: https://www.cncele.co