. Electric railway journal . ism aspossible. The motor relay will continue to revolve if No. 36 isnot closed. Contact 7C will drop out No. 8; contact IDwill not cause any action because interlocking relay is open. After No. 36 closes, the next time that con-tacts 1A and IB are made No. 19 will close which inturn will close the running switch No. 11. The master relay panel is shown in one of the illus-trations; the mounting of the motor relays on brack-ets behind the panel are shown in another. The alter-nating-current switches are mounted on a third panelwhich may be located in the positi
. Electric railway journal . ism aspossible. The motor relay will continue to revolve if No. 36 isnot closed. Contact 7C will drop out No. 8; contact IDwill not cause any action because interlocking relay is open. After No. 36 closes, the next time that con-tacts 1A and IB are made No. 19 will close which inturn will close the running switch No. 11. The master relay panel is shown in one of the illus-trations; the mounting of the motor relays on brack-ets behind the panel are shown in another. The alter-nating-current switches are mounted on a third panelwhich may be located in the position most economicalwith respect to use of cable. The Direct-Current Control IsVery Simple The converter is connected to the line through a seriesof cushioning resistors which are short-circuited inthree sets. The closing of the main contactors is gov-erned by current-limit relays which prevent the cuttingout of the resistors in case the current demand is inexcess of the current rating. The assembly of contact-ors and current-. THE POLARIZED MOTOR RELAY(NO. 7) limit relays isshown in stillanother illustra-tion. The sta-tion is held onthe line bymeans of a cur-rent relay () which is setto operate atabout 15 percent of normalfull load. In itsde-energized po-sition this relaycloses a circuitthr o u g h the time relay No. 27. No. 27 consists of a smallshunt-wound direct current motor with a magneticclutch driven through reduction gearing having aratio of 19,800 to 1. The clutch drives an armwhich closes the contact at the end of the stroke, short-circuiting the coil of No. 3 and thus shutting down thestation. If the load demand comes on while the time relay isoperating then No. 13 picks up, opening the circuit tothe time relay and de-energizing the clutch. Thus themoving arm is allowed to return to its back stop. Thisclutch action provides an instantaneous reset whichprevents the time relay from having a cumulative char-acteristic. Safeguarding the Substation Apparatus An automa
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyorkmcgrawhillp
