The PARKER Hydraulic Motor is high quality! Parker s unique two-speed motor utilizes two separate IGR power elements on a common shaft. An integral selector valve shifts between high torque, low speed (parallel) operation and high speed, low torque (series) mode in a ration of 2:1. The use of two power elements eliminates the deficiencies of traditional, single power element designs. In the high torque mode, the motor delivers twice the torque and half the speed that it does in the high speed mode. The selector valve can be open or closed center and may be actuated by an external pilot or optional solenoid valve. The open center selector valve can be shifted on the fly while the motor shaft is rotating under load. The selector valve is spring loaded to return to its pilot-pressure-off position. Normal mode of operation is field changeable and can be selected as series or parallel. Pilot pressure must be 300 psi higher than motor case or outlet pressure and may be as high as typical hydraulic system operating pressure.