1288 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1954 

 5.0 



3.0 





2.0 



0.5 



0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 



COEFFICIENT OF FRICTION, /y 



Fig. 11 — Derivative of governor speed with respect to governor input torque 

 versus coefficient of friction. 



ditions: as received, governor case cleaned with acetone, damp atmos- 

 phere, and SAE 10 petroleum base oil in the case. Each of the governors 

 were initiallj' adjusted to 10 pulses per second with the governor cases in 

 the "as received" condition. The gov^ernors were then removed and the 

 cases and governor studs were cleaned with acetone. The governors were 

 then reassembled and the new speed recorded. During this procedure 

 extreme care was exercised so as not to disturb the governor spring ad- 

 justment. Speed was next recorded for the damp atmosphere condition, 

 and finally for the condition with one drop of SAE 10 oil in the governor 

 case. For these last two conditions the governors were not removed from 

 the dials. 



The average speeds recorded for the four conditions are plotted on the 

 theoretical speed curve of Fig. 12. The points were arbitrarily placed on 

 the theoretical curve. Xo attempt was made to determine the exact co- 

 efficient of friction values corresponding to the four conditions. In this 



