Electrical news and engineering . r<rd: - /^artr _ /=our -Wiro C:trc:L//f overload feature of the circuit breakers at the sending endof the line,»shown at C and D Fig. 4. If the short circuit occurs as at SV Fig. 4, the selec-tive watt relay A immediately closes its contacts whilethe selective watt relays at 1! keep their contacts the current has reached a pre-determined value, the re-verse current relays on both A and B close their con-tacts, tripping out circuit breaker at A. The overloadfeatures at C trip out the sending end and so the defec-tive line is automatically disconnec
Electrical news and engineering . r<rd: - /^artr _ /=our -Wiro C:trc:L//f overload feature of the circuit breakers at the sending endof the line,»shown at C and D Fig. 4. If the short circuit occurs as at SV Fig. 4, the selec-tive watt relay A immediately closes its contacts whilethe selective watt relays at 1! keep their contacts the current has reached a pre-determined value, the re-verse current relays on both A and B close their con-tacts, tripping out circuit breaker at A. The overloadfeatures at C trip out the sending end and so the defec-tive line is automatically disconnected from the system, per-mitting service to continue over the good line. The reversecurrent relay which was developed before this combinationwas devised also has a selective action between current in the. r/G. e Cur\/e showing ODerrat/on o/ r-i^/a/ iv/fhcurrant and i/o/taaa- a^jpZ/efi:/- power direction and current in the reverse direction. Thisfeature is supplied by means of a shunt winding whichgives it somewhat the nature of a wattmeter. When the volt-age is normal, the operation of the reverse current relay isshown by Fig. 2, , s-uppose the upper index to be set at2: 1 ampere in the reverse direction will close the relaycontacts, while 7 ampcrcr are required in llu- pi>wer direc-tion to close the contacts. If a short circuit occurs close to the rebiys with con-sequently very little voltage at the relays, the reverse cur-
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Keywords: ., bo, bookcentury1800, bookdecade1890, bookidelectricalnewsen20donm
