618 



BELL SYSTEM TECHNICAL JOURNAL 



delivers an output voltage e proportional to its shaft angle d. Thus, the 

 ratio of e to is a transfer stiffness constant St . The synchro circuit con- 

 sists of a synchro generator connected to a control transformer, and delivers 

 an output voltage e proportional to 61 — 62, the angular difference between 



ELECTRICAL 



INDUCTANCE 



L 



4J 



e = L 



MECHANICAL 



INERTIA 



-T — J 



. de 

 dt 



FLYWHEEL 



COMPLIANCE 

 C 



L? 



T = r /edt 



SPRING 



RESISTANCE 



LTJ 



e=RL 



MECHANICAL 

 RESISTANCE 



R 

 0-VW--0 



Ll 



T=Re 



DASHPOT 



SERIES L-R-C 

 L R C 



"^'-dt^'^^^i^^ 



^-""df'"^*i/^^^ 



Fig. 1 — Electrical-mechanical analog}'. 



the two shafts. Thus the action of the synchro pair is that of a combined 

 transfer stiffness and differential. The tachometer is a generator which 

 produces an output voltage e proportional to 6, the angular speed of its 

 shaft. The ratio of e to is a transfer resistance constant Rt . 



