Power turbine speed control for turboprop engines

Claim 1

A GOVERNING SYSTEM FOR AN ENGINE COMPRISING A FUEL CONDUIT TO SAID ENGINE, A FUEL VALVE IN SAID CONDUIT, SERVOMOTOR MEANS FOR CONTROLLING THE POSITION OF SAID FUEL VALVE, AND MEANS FOR CONTROLLING SAID SERVOMOTOR MEANS INCLUDING A FLOATING LINK AND A PILOT VALVE ATTACHED TO SAID LINK, A PROPORTIONAL ALL-SPEED GOVERNOR ADAPTED TO EXERT A FORCE ON SAID LINK INCLUDING AN ADJUSTABLE SPEED RESPONSIVE DEVICE FOR PRODUCING A FORCE VARYING WITH THE SPEED OF SAID ENGINE AND SPEED SELECTING MEANS RESPONSIVE TO VARYING LOAD CONDITIONS FOR PRODUCING A FORCE IN OPPOSITION TO SAID SPEED FORCE, AND AN INTEGRATING ALL-SPEED GOVERNOR ADAPTED TO EXERT A FORCE ON SAID LINK INCLUDING A CAM IN CONTACT WITH SAID LINK, MEANS DRIVEN BY SAID ENGINE FOR PRODUCING A VOLTAGE WHOSE AMPLITUDE VARIES WITH THE SPEED OF SAID ENGINE, MEANS PRODUCING A VOLTAGE WHOSE AMPLITUDE IS PROPORTIONAL TO A DESIRED SPEED AND FOR COMPARING SAID VOLTAGES TO PRODUCE A SPEED ERROR SIGNAL, AMPLIFICATION MEANS FOR AMPLIFYING SAID SPEED ERROR SIGNAL, AND AN ELECTRIC MOTOR DRIVEN BY SAID AMPLIFICATION MEANS FOR POSITIONING SAID CAM.