HSD2 series intelligent motor protector (hereinafter referred to as protector) has ?protection function of overload,phase failure,unbalance,under load, grounding protection , stall ,blocking, starting overtime, temperature (PTC), over voltage, under voltage, under power ??and has starting method of direct start, bidirectional start, star delta start, self coupling transformer step-down start and has ?measurement function of three phase current, three phase voltage, active power ?and has ?communication function ?of ?RS485 interface, MODBUS-RTU communication protocol. The protection device adopts the modular product design structure, including the main module (protection control function), mutual inductor detection module, field bus communication module. ?According to the need to select the protection function module or accessories and contactors and other electrical components can constitute the motor protection control unit which has the functions of direct control, panel indication, signal alarm and field bus communication and ?is suitable for the fields of coal mine, petrochemical industry, metallurgy, electric power, shipbuilding, civil engineering, etc.