1118 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1954 



coils. In normal operation, these relays are not energized continuously, 

 but operate only for short intervals while a talking circuit is established. 

 The design provides for replacement of a coil winding in the field, but 

 this is not expected to be necessary except in rare cases. 



Molded Wire Spring Subasseinhlies 



Wire spring subassemblies for a 30-contact relay are shown in Fig. 8. 

 The two single wire subassemblies differ only in their terminal arrange- 

 ment. The twin wire subassemblies are identical. Therefore only three 

 basic molded parts are required which supply all needs for all new produc- 

 tion relays. The wire spring sections are molded in continuous ladders^ 

 as in the general purpose relay. Spring bending, contact welding and 

 coining^ and terminal forming for solderless wrapped connections,^" 

 are performed in automatic tools developed by Western Electric Com- 

 pany engineers. A comparison of the wire spring parts used in two new 

 30 make relays and the corresponding parts of a 60-make flat spring 

 relay, is shown in Fig. 9. This illustrates the reduction in parts and 

 simplicity of wire springs compared with flat springs. Seven types of 

 subassemblies are used in the twelve layers required for an equivalent 

 flat spring relay. 



Terminals of the single wire subassemblies are formed for multiple 

 wiring, and therefore differ in length and configuration. An improved 



CORE 



I 



y 



ARMATURE 





ARMATURE 

 HEEL STOP 



Fig. 6 — Magnetic structure of the new relays. 



