A GOVERNOK FOR TELEPHONE DIALS 



1277 



Table II 



Substituting these values in the general speed eciuation, 

 CO = g tanh { - -\- In \/Z ) 



gives the velocity of the dri\'e bar governor at any time t measured from 

 the moment the governor reaches the critical velocity, i.e., when the 

 friction studs first touch the inside of the governor case. (Table II.) 



For governor speeds from start of rotation up to the critical velocity, 

 it is assumed that the system rotates as a simple fly-wheel, therefore from 

 ecjuation (1) 



t' = 



~g7 



121.8(7.4) 



0.0668 seconds 



13,500 



This time of 0.0668 seconds determines the slope of the straight line 

 portion of the theoretical speed-time curve shown on Fig. 6. 



Fhj-Bar Governor 



The data given in Table III applies to the fly-bar governor shown 

 schematically in Fig. 7. Substituting the values given in this table in the 

 steady state speed eciuation for the fly-bar governor, 



(ji — q = 



-4 



G(d - nc) + Mmcoq^ 



coo = 118.5 radians/sec. 

 >nd from equations (7), (8) and (9): 



g = 0.609 h = 9,560 h/q = 76.4 



A = 36.35 



Substituting these values in the general speed equation gives the 

 velocity of the fly-bar governor at any time (t) measured from the 

 moment braking begins, Table IV. For this particular fly -bar design, the 



