1272 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1954 



The comparative design shown in Fig. 5 is a conventional fly-bar type 

 governor consisting of two weights each pivoted at the end of a fly -bar 

 which is fixed to a shaft. As the shaft accelerates during run-down, the 

 weights move outward under the influence of centrifugal force and are 

 restrained in their motion by the tension of the go\Trnor spring. At a 

 certain speed the friction studs contact the inner surface of the governor 

 case. The governor gradually decelerates until the input torc[ue to the 

 governor is balanced by the stud-to-case frictional loss and the governor 

 shaft and dial theoretically rotate at constant speed. It will be noted in 

 this configuration that only the torque produced by the stud-to-case 



GOVERNOR 

 ,^ CASE 



RUN-DO\WN 



Fig. 4 — Schematic of drive-bar governor. 



F — Force applied by torque on governor weights 

 Fn — Normal force of case acting on studs 

 F s — Force exerted by spring when studs touch case 

 Fm — Centrifugal force acting at center of gravity of weight 

 /x — ■ Coefficient of friction 



/o — Moment of inertia of the governor about center shaft 

 CO — Angular velocity of governor 



wo — Critical angular velocity at which studs just touch the case 

 in — Mass of each weight 



?'o — Radius to the center of gravitj^ of each weight 

 r — Radius of governor case 

 a — Stud angle 

 Neg. Rotation — Run down of governor 



