1. The start, stop or emergency stop button of the oil pump of the hydraulic shear is damaged;

　　2. Overload protection thermal relay is damaged;

　　3. The AC contactor coil of the hydraulic shear is open or damaged;

　　4. Loose or damaged terminal of three-wire AC circuit;

　　5. The oil pump motor of the hydraulic shear is damaged or the connector is loose.