A GOVERXOR FOR TELEPHONE DIALS 1283 



each other. A minimum d is therefore fixed by interference of the parts 

 themselves. Inspection of the governor mechanism also shows that even 

 if the interference problem were not Hmiting, the weight turning angle 

 imposes a further restriction on the (/ value. The life of a governor is 

 considered to end when the friction material is worn to the point of 

 allowing the weight to touch the inside of the case. Because of this 

 initially large weight motion, little material is provided for wearing and 

 hence the possible life of the mechanism is reduced. In the design of the 

 drive-bar governor, the stud angle, a, was made as small as manufactur- 

 ing techniques would permit. The stud angle is 22° from the weight piA'ot 

 with a corresponding d = 0.390 cm. 



Since both governors under study were designed to operate in the 

 case of the same dial the terms shown in Tables I and III which apply 

 in the friction equations (11 and 12) are identical. This identity of terms 

 indicates that both type governors should exhibit identical frictional 

 characteristics. Fig. 8 represents a plot of the dw/dii for ^^arious governor 

 input torque values. One set of curv^es applies. The range of torciue values 

 covered by the curves is from zero to the forcing condition at fifteen 

 times normal motor spring torciue. Curves for coefficient of friction 

 values, 0.05, 0.10, 0.20, 0.35, are shown as encompassing the extremes in 

 operating range. 



Speed with Respect to Input Torque 



For the drive-bar governor, the partial derivative of speed with 

 respect to torcjue is determined as follows from the steady state speed 

 equation. 



G{d - ijlc) + Mmcoo^ - firjG/e 



CO — Q — ' ' 



Mil 



Taking the derivative of w with respect to G gives: 



^ = 1 

 dG 2 



G{d — iic) + ilZ/xwo" — nrjG/e 



and 



doi 1 {d — fjLC — fjLTJ/e) 



{d — ijlc — fJirjG/e) 



(13) 



dG 2 MfjLu 



where 



M = 2 ynrrob 

 For the fly-bar go\ernor the deri\-ative of co with respect to G can be 



