Technical Paper Volume 265-280

Technical Paper Volume 265-280

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 edition. Excerpt: ...therefore their proper operation is essential to the safe and efficient conduct of the mine. Signal circuits, whether placed in shafts, slopes, or along haulage roads, should be so installed as to be free from the liability to mechanical injury or interruption to service, and should be supported on insulators or run in conduit. Where there is danger in accidental contact, the same precautions should he taken as for power circuits. Rules found in the Washington State code (see Table 5) follow: Electrical signaling: precautions.--All proper precautions shall be taken to prevent electrical signal and telephone wires from coming into contact with the other electric conductors, whether insulated or not. Character of equipment.--Bells, wires, insulators, contact makers, and other apparatus used in connection with electric signaling underground, shall be of suitable design, of substantial and reliable construction, and erected in such a manner as to reduce the liability of failure or false signals to a minimum. SIGNAL CIRCUITS FOB USE IN GASEOUS MINES. Even primary battery signal circuits used for operating bells might readily cause an ignition of gas, and signal-circuit operation from power circuits would be almost sure to cause an explosion were the wires to become short circuited and arcs or sparks to result at a point where inflammable gas had accumulated. Therefore, open wiring for signal circuits, whether insulated or not, should not be used in a gaseous section of a mine. The only specific references to signal circuits in gaseous mines or sections of a mine are found in the Washington and Pennsylvania (bituminous) codes, and are confined to the limitation of voltage of such circuits in gaseous portions of a mine. The quotation from more

Product details

  • Paperback
  • 189 x 246 x 10mm | 340g
  • United States
  • English
  • black & white illustrations
  • 1236766822
  • 9781236766823