Electro-hydraulic control system for governors

摘要

The governor of the invention consists of an output solenoid having a plunger operatively connected to the mechanism to be controlled. The output solenoid is a "bang-bang" type such that full power or no power is delivered to the solenoid even for small errors between the desired operating condition and actual condition of the mechanism to be controlled. The output solenoid is connected in a hydraulic circuit with a control solenoid having a control valve such that the movement of the fluid through this circuit is regulated by the control solenoid. The control solenoid is of the proportional type such that the control valve's position is directly related to the difference between the actual operating condition and the desired operating condition of the mechanism to be controlled. A position sensor is provided on the output plunger to provide feedback to the controller such that as the output plunger approaches the desired position the control valve will gradually begin to close to thereby decrease the speed of movement of the output plunger to avoid overshoot of the desired position. Once the output plunger is in the desired position and the control valve is closed the output plunger is locked in position such that the power delivered to the coil of the output solenoid can be maintained at an intermediate level.