Practical Dynamo Building: With Detail Drawings and Instructions for Winding

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Nixon-Jones printing Company, 1893 - 143 стор.
 

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Сторінка 118 - When pieces of charcoal about an inch long and onesixth of an inch in diameter, were brought near each other (within the thirtieth or fortieth part of an inch) a bright spark was produced, and more than half the volume of 'the charcoal became ignited to whiteness, and by withdrawing the points from each other a constant discharge took place through the heated air, in a space equal at least to...
Сторінка 98 - Flexible cord must not be used except for pendants, wiring of fixtures, portable lamps or motors, portable heating apparatus or other portable devices.
Сторінка 91 - ... c. Must be at least seven feet above the highest point of flat roofs, and at least one foot above the ridge of pitched roofs over which they pass or to which they are attached.
Сторінка 90 - ... station operates continuously. c. Data obtained from all tests must be preserved for examination by insurance inspectors. These rules on testing to be applied at such places as may be designated by the association having jurisdiction. MOTORS. 8. MOTORS:— a. Must be wired under the same precautions as with a current of the same volume and potential for lighting. The motor and resistance box must be protected by a double pole cut-out and controlled by a double pole switch, except in cases where...
Сторінка 109 - ... dangerous extent. Companies furnishing electricity from central stations must enter into an agreement with the New York Board of Fire Underwriters, binding themselves to test their lines for ground connections at least once every day (and preferable three times per day) , and to report the result of such tests to the Board weekly.
Сторінка 97 - All conductors for fixture work must have a waterproof insulation that is durable and not easily abraded, and must not in any case be smaller than No. 18 B. & S., No.
Сторінка 107 - ... cut-out where the wires enter the building, or where they leave the main line, on the pole or in the conduit. These switches should...
Сторінка 96 - Fuses should have contact surfaces or tips of harder metal, having perfect electrical connection with the fusible part of the strip. The use of the hard metal tip is to afford a strong mechanical bearing for the screws, clamps or other devices provided for holding the fuse. Fuses should be stamped with about 80 per cent of the maximum current they can carry indefinitely, thus allowing about 25 per cent overload before the fuse melts.
Сторінка 102 - ... Outside wires must be covered with at least two coatings, one of insulating material impervious to water, next to the wire, and the other of some substance fitted to resist abrasion or like mechanical injury, and must be firmly secured to substantial approved insulators, adequately supported. All " tye wires" or those used to secure the conductors to the "insulators" must be themselves covered with waterproof insulating and mechanically resistant material similar to that used on the conductors...
Сторінка 89 - For inside use, the light must be surrounded by a globe which must rest in a tight stand, so that no particles of melted copper or heated carbon can escape ; and when near combustible material, this globe must be protected by a wire netting. Broken or cracked globes must be replaced immediately. Unless a very high globe is used, which closes in as far as possible at the top, it must be covered by some protector reaching to a safe distance above the light.

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