. The Street railway journal . aker will operate on the current due to a December 31, 1904.] short-circuit. If some simple method can be devised for hastilybut reliably testing the adjustment of car breakers in place—daily if necessary—a step will have been taken toward removingthese safety devices from the list of electric railway combusti-bles. The import of the present article is to suggest a methodwhereby the adjustment of a car circuit breaker can be testedin from one to three minutes, and unless the test shows thatbreaker parts must be renewed, an adjustment will require butlittle longer
. The Street railway journal . aker will operate on the current due to a December 31, 1904.] short-circuit. If some simple method can be devised for hastilybut reliably testing the adjustment of car breakers in place—daily if necessary—a step will have been taken toward removingthese safety devices from the list of electric railway combusti-bles. The import of the present article is to suggest a methodwhereby the adjustment of a car circuit breaker can be testedin from one to three minutes, and unless the test shows thatbreaker parts must be renewed, an adjustment will require butlittle longer. The test does not involve the use of measuringinstruments, excepting initially for purposes of calibration, andthereafter occasionally as a factor of safety in checking adjust-ments, and can be conducted by any one to whom it may havebeen explained. In the accompanying diagram, TT is the house service trol-ley wire, and t a short length insulated from TT by linebreakers on both ends. Circuit breakers a, b, in series with. WIRING DIAGRAM FOR CHECKING CAR CIRCUIT BREAKERS each other, are also in series with switch c, fuse d and variableresistance r, which may be a water rheostat. There is on cir-cuit breaker a, a pair of contacts a, which, in connection witha blade carried on or operated by the moving member of thebreaker, closes the circuit at a immediately after the regularcircuit breaking contacts have been effective in opening thecircuit at a ; i. e., operation of breaker a momentarily opens thecircuit, then closes it immediately. The short section of trolleywire / cannot have connection with live trolley wire TT, ex-cept through test path T-a-b-c-d-r-t. When all breakers,switches and fuses of this path are closed, section t is alive;under this condition if the trolley wheel of a car bears upagainst t and one of its controllers is advanced to an operatingnotch, the car will take current through its normal workingcircuit, including car breakers j and k, and would tend to
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
