1286 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1954 



0.2 [ 0.4 0.6 0.8 1.0 1 1.2 1.4 1.6 1.8 2.0 2.2 



C IN CENTIMETERS 



L. 



U- 



_FLY-BAR ARM LENGT 

 (0.920 CM) 



-J 



Fig. 10 — Design diagram for drive-bar type governor. 



tion for these particular friction values. The point A on the d and c 

 circle denotes the d and c values which result from the stud being at 

 a. = 22°. The off-set appears because stud-to-case contact is not made 

 on the center line of the stud. The points 1, 2 and 3 are all below the 

 point, A, established by the minimum pennissible angle, a = 22°. This 

 indicates that the fly-bar governor has its dw/dG equal to zero at some 

 coefficient of friction value higher than /x = 0.425. As previously deter- 

 mined in this value is ju = 1.08. 



Fig. 10 represents the design diagram for the new drive-bar governor. 

 Here again, the large semi-circle is a plot of all d and c values which con- 

 form to the geometry of this governor mechanism. Point A is determined 

 by the stud angle a = 22°. The straight lines represent the limiting equa- 

 tions for jLi = 0.425, 0.25 and 0.05 and are shown intersecting the d and c 

 circle at 1, 2 and 3 respectively. For this particular governor, the line 

 representing ju = 0.425, 



d - 0.425 (c 4- rjfe) = 



intersects the d and c circle at the point A . This is possible by making the 

 term (nrj/e) equal to 0.238. The intersection of this curve at A indicates 

 that there will be zero change in speed for a given change in input torque 

 to the governor when the stud-to-case coefficient of friction value is 

 0.425. 



