186 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1954 



analytical presentation, as noted in Part I, of fast release time data is 

 not now as advanced as the operate time data. 



The material presented here describes the present state of the art. 

 For slow releasing relays, the performance can be predicted with ac- 

 curacy. For fast relays, while the general pattern is known, accurate 

 means for estimating variations have not been developed. The present 

 engineering of releasing relay circuits therefore, depends upon specific 

 measured data in chart form, for each condition. 



ACKNOWLEDGMENTS 



The analyses leading to the forms of data presentation for the several 

 types of relay timing information are the results of contributions from 

 many people. In particular, the early nomograms for load controlled 

 operation were developed by P. W. Swenson. The node method for 

 separation of series releasing relays shunted by an RC network was 

 developed by R. H. Gumley. The graphical method for design of opti- 

 mum series windings was developed by Mrs. K. R. Randall. To her, I 

 am also indebted for preparation of all the charts of measurements. 



REFERENCES 



1. H. N. Wagar, Economics of Telephone Relay Applications, page 218 of this 



issue. 



2. M. A. Logan, Dynamic Measurements on Electromagnetic Devices, B.S.T.J., 



31, pp. 1413-1466, Nov., 1953. 



3. R. L. Peek, Principles of Slow Release Relay Design, page 187 of this issue. 



4. R. L. Peek and H. N. Wagar, Magnetic Design of Relays, page 23 of this 



issue. 



