Principles of naval engineering - Historic Naval Ships Association

Chapter 25. -NEW DEVELOPMENTS IN NAVAL ENGINEERING>—II-Ii-d»MP>— IFigure 25-23.— Block diagram of throttle control system.140.95motor to drive in a direction to open the throttlevalve. A negative input will close the throttlevalve. The SCR power package will be inhibitedby limit switches if the motor travel exceeds apredetermined point of travel.The pilot motor positions a pilot valve in thehydraulic actuator which ports oil in the properdirection to correctly position the throttle valve.A reference signal for throttle position, whichis controlled by the pilot motor, is fed back to thesumming junction. This section cancels the inputsignal when the desired valve opening is reached.During direct electrical control of the throttle,the contacts in the throttle location switchchange the circuitry eliminating the regulatedsignal and setting up the circuitry for signalsfrom the direct throttle switches.During manual operation, the manual clutch isengaged and the hydraulic actuator is inhibited. Inaddition, the hydraulic system is vented to preventa hydraulic lock and permit the movementof the handwheel for manual throttle control.A tachometer generator on the shaft producesan output signal that is fed back as the speed651