Electro-Pneumatic Interlocking

Electro-Pneumatic Interlocking

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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. 1914 edition. Excerpt: ...subjected to neither high electric stresses by working currents, nor to high temperatures resulting from excessive currents due to short circuits that occasionally occur accidentally at terminals of magnets and like exposed conductors during repairs or inspection. Electro-magnets employed for the operation of the pin valves of switch and signal movements are wound to a resistance of 400 ohms each. Many of these remain upon closed circuit for long periods, one magReasrtance net for each switch always, and one for each signal during its display of proceed. Electro-magnets adapted to the control of lever movements at the machine are wound to 130 ohms each because of their heavier duty, but these are energized for very brief periods only so that the greater currents thus employed by them do not materially affect the total economy of current. The 400 ohm magnets of switches and signals may, obviously, be operated from the interlocking machine through conductors having a total of 40 ohms resistance with but 10% drop, an allowance usually permitted in the general transmission of electric energy. Assuming the switch or signal to be 1000 feet from the tower (an excessive average distance) its operation, with but 10% drop in its external circuit, would be possible with a copper conductor Conductor, of No. 23, B. & S. gauge. Consideration of mechanical strength, however, prohibits the use of such a wire in this service, and larger wires are employed in practice which practically eliminate all losses in external circuits. This is in marked contrast with the losses that occur in the circuits of the motors of switches operated directly from the levers of electric interlocking machines, where during the very times when the full e. m. f. of the...show more

Product details

  • Paperback | 28 pages
  • 189 x 246 x 2mm | 68g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236925734
  • 9781236925732