Microcontroller based. Sensing voltage, current and temperature. Protecting against Phase Failure, Unbalance, Phase sequence, Under/over voltage, overloading, winding over temperature, Over current/Short circuit, locked rotor, Auto/Manual resetting, Adjustable trip settings for UV/OV, UC/OC, O/L, Locked rotor & earth fault. On delay & start-up delay adjustable, 2x1CO output relays and serial communication port.