The YB-KBZ motor microcomputer comprehensive protection switch uses the PIC microcontroller produced by the internationally renowned Microchip company as its core component. The product is completely digitally controlled and detects current signals through a built-in high-precision current transformer; A mathematical model established based on the heating characteristics of electric motors can provide good protection for various AC motors that may experience faults such as phase failure starting, locked rotor, grounding, overcurrent, undercurrent, phase failure operation, and low-voltage three-phase imbalance caused by high-voltage side phase failure of power transformers; Multiple functions can be set (overcurrent, undercurrent, leakage current, three-phase imbalance, starting delay, overcurrent protection characteristics, etc.), with high setting accuracy, wide range, and simple operation; The digital display shows the operating current of the motor, without the need for an external current transformer. The current range includes 1-200A, and it can achieve motor reclosing (shaking and then tripping). And it has a 4-20mA transmission output port, which can also accumulate the total running time of the motor and achieve star delta conversion control. The product follows the installation structure of a thermal relay, and the main circuit adopts a perforated design to avoid contact and heat generation with the main circuit. The internal components are coordinated with circuit breakers and contactors to form a magnetic start protection system. The most suitable for small electromechanical complete sets of equipment, such as light industry, food, medicine, chemical machinery, small woodworking machine tools, kitchen machinery equipment, crushers, small (submersible) water pumps, aerators, water pumps, small fans, fans, small air compressors, small construction machinery, mixers, polishing machines, conveying equipment, centrifuges, rice mills, tea makers, small agricultural machinery and building power distribution, metallurgy, coal mines, petrochemicals, fire protection, railways and other direct starting system protection.