Profile: Great Wall Energy International Limited provides high performance downhole mud motors, shock tools, drilling jars, casing packers, fishing tools, and accessory equipment for the oil & gas drilling industry. Hydraulic motor is a mechanical actuator that converts hydraulic pressure & flow into torque and angular displacement (rotation). The hydraulic motor is the rotary counterpart of the hydraulic cylinder. Conceptually, a hydraulic motor should be interchangeable with a hydraulic pump, because it performs the opposite function - much as the conceptual DC electric motor is interchangeable with a DC electrical generator.