Automatic control by microcomputer (PC), with functions of start, stop, reverse, overload automatic reverse, feature return and over-loading returns automatism, with characteristics of big torque in low speed, low noise. Convenient to change blade by split bearing block. Suitable for crushing the big solid material like television, washing machine, shell of refrigerator, big size pipe, pipe fittings, forklift splint, tyres, packing barrel, aluminum, copper and steel less than 5mm.