. The Bell System technical journal . CROSSBAR DIAL TELEPHONE SWITCHING SYSTEM 87 Multi-Contact Relay The multi-contact relay used in the crossbar system is shown inFie:. 5. It resembles in design the vertical unit of a crossbar switch. %. Fig. 5—Multi-contact relay. The relay is provided in four sizes in respect to the number of contacts,namely, in 30, 40, 50 and 60 sets of individually insulated contacts,all of which are of the normally open type which are closed when themagnets of the relay are operated. Each relay is provided with twoseparate magnets, armatures and associated groups of spr
. The Bell System technical journal . CROSSBAR DIAL TELEPHONE SWITCHING SYSTEM 87 Multi-Contact Relay The multi-contact relay used in the crossbar system is shown inFie:. 5. It resembles in design the vertical unit of a crossbar switch. %. Fig. 5—Multi-contact relay. The relay is provided in four sizes in respect to the number of contacts,namely, in 30, 40, 50 and 60 sets of individually insulated contacts,all of which are of the normally open type which are closed when themagnets of the relay are operated. Each relay is provided with twoseparate magnets, armatures and associated groups of springs, andboth magnets are energized in parallel in order to close all of thecontacts. By operating the two magnets independently the structurescan be used as two separate relays, each equipped with 15, 20, 25 or30 sets of contacts. The relay occupies a mounting space approxi-mately 2 X 11 and is provided with a cover. All contact springs are equipped with twin contacting surfacessimilar to the contacts used on the crossbar switch except that theyare composed of solid bars of precious metal due to the heavy dutyrequirements. To facilitate wiring, these relays are manufacturedwith two types of wiring terminals. In one type the mova
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
