Patent ID: 8269360

Claim:
A hydraulic system comprising: a variable displacement hydraulic pump drivably connectable to a primary power source, the pump having an inlet for receiving fluid, an outlet for discharging fluid under pressure, and a pump displacement input; a hydraulic motor having an inlet for receiving fluid under pressure and an outlet for discharging spent fluid; a fluid circuit including a supply conduit for conducting fluid discharged by the pump to the motor and a return conduit for returning fluid discharged by the motor to the pump; a pump displacement control cooperating with the pump displacement input in order to vary the displacement of the pump; and a control circuit in communication with the pump displacement control for controlling the pump output such that the motor is driven at a constant rotational speed to thereby drive an auxiliary power source drivably connected to the motor at a constant rotational speed despite fluctuations in rotational speed of the primary power source.