. Journal of electricity, power, and gas . thin town limits. The oldmethod of attaining this result was either by the useof large knife blade switches, manually operated, orof third rail shoes manually lowered. Both of thesesystems are cumbersome and inconvenient. An auto-matic device known as a change-over switch was,therefore, developed for this service. This change-over switch, an exterior view of whichis shown by Fig. 6, consists briefly of a pair unit ofelectro-pneumatic valves operating pneumatically ablock contact held in guides, and operated therein,wiping fingers in contact giving the
. Journal of electricity, power, and gas . thin town limits. The oldmethod of attaining this result was either by the useof large knife blade switches, manually operated, orof third rail shoes manually lowered. Both of thesesystems are cumbersome and inconvenient. An auto-matic device known as a change-over switch was,therefore, developed for this service. This change-over switch, an exterior view of whichis shown by Fig. 6, consists briefly of a pair unit ofelectro-pneumatic valves operating pneumatically ablock contact held in guides, and operated therein,wiping fingers in contact giving the desired changes inconnections to either trolley or third rail circuits. Thisapparatus is entirely automatic and is operated andprotected by two interlocking relays respectively con- April 23. 1910] JOURNAL OF ELECTRICITY, POWER AND GAS 381 nected to trolley circuits and third rail circuits. Thedetail of these connections is shown in the Dias;ram whole being: substantially protected by cast iron capbolted to the main switch and plate. 1°. Temperature test on . L Pneumatic Unit Switch! H - - -n-rt: One inch cbntact - -I- March 20.^ ?, L 50 m 200 300 Pounds pressure on contact 460 JJ3 Pig. 5. of Connection of Main and Control Wiring with UnitSwitch Control, as shown on page 384. Line Switch. Shown by Fig. 7 closed and by Fig 8 with coversremoved. Current from the trolley or third rail connectionsafter passing through the change-over switch passesthen through the line switch. The line switch is asingle unit of identical construction with the switchgroup. It is an independent circuit-breaker providedwith automatic overload trip, the trip consisting of a
Size: 1599px × 1562px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookidjo, booksubjectelectricity
