Nin\ MlL'l'ICOXlAcr IIKLAY 1113 



3. No contact chatt(M-. 



4. No false actuation due to armature rebound. 



5. No magnetic or xihrational inteit'erence. 



(■). 120-ohni and 27.")-olun coils, to work with e(iuipment ali-eady in use. 



Equipminl 



1 . Lower nianufacturing costs. 



2. [{educed mount in<>; s])a('e. 



3. Terminal ai'i'aniiement tor multiple wirinjj; same as at present, or 

 equivalent from a wiring; stand])oint. 



Maintenance 



1. Contact failures due to dirt or insulating films should lie sub- 

 stantially equal to and preferably less likely than in the present relay. 



2. No contact locking due to contact erosion. 



3. Contacts should be replaceable in the field. 



4. Coil winding should be replaceable in the field. 



5. Field adjustment should be reduced to a minimum. 



Replacement Relay 



The design objectives also included modification of the new relay, if 

 possible, to replace multicontact relays in existing crossbar ecjuipments. 



Design History 



During the early stages of this development, considerable effort was 

 directed toward improving the present flat spring multicontact relay. 

 Later, many experimental models were constructed, to investigate other 

 flat spring, and wire spring designs, and several contact actuating meth- 

 ods. The most favorable designs of flat and wire spring multicontact re- 

 lays were compared, and their differences were resolved by an analysis 

 of manufacturing tolerances and their effect on performance and cost. 

 Preliminary estimates of initial cost were only slightlj; in favor of the 

 wire spring design. However, the wire spring relay offered significant 

 advantages in (1) higher speed, longer life, less chatter, (2) better manu- 

 facturing control of tolerances, (3) less maintenance, and (4) possibilities 

 of future cost reductions as further improvements are made in mech- 

 anized methods of manufacture. 



DP^SCRIPTION OF THE NEW RELAY 



General 



Stationary single wire and moving twin wire spring subassemblies 

 are arranged in alternate layers attached to the core and mounting 



