1046 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1952 



to the operated position, and back again. This is measured at the center- 

 h'ne of the card and hence is also the card motion. In the unoperated 

 position the armature rests against a backstop, which is part of the core 

 plate. In the operated position it rests against 0.006-inch thick non- 

 magnetic separators which prevent the armature from touching the core. 

 The ordinate shows the spring load, which opposes the armature motion 



0.01 0.02 0.03 0.04 | 0.05 



armature travel in inches 



released position 

 (against backstop) 



Fig. 17 — Typical load and pull characteristics of a wire spring relay with twelve 

 early break-make transfer contacts. 



