. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. rbons aredrawn apart. The electro-magnet is covered with more convolutions at the base than at the top,so that when the current becomes weakened by the separation of the carbon points, it may have itsmagnetic effect still powerfully maintained. Fig. 1166 is a section of one of the Brush lamps ; A is a helix of insulated wire, A an insulatedplate, C an iron core, B a rod, D a brass ring, F F carbons, G lower carbon holder. The Brushlamp contains no clockwork or similar mechanism, and the movement of the upp
. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. rbons aredrawn apart. The electro-magnet is covered with more convolutions at the base than at the top,so that when the current becomes weakened by the separation of the carbon points, it may have itsmagnetic effect still powerfully maintained. Fig. 1166 is a section of one of the Brush lamps ; A is a helix of insulated wire, A an insulatedplate, C an iron core, B a rod, D a brass ring, F F carbons, G lower carbon holder. The Brushlamp contains no clockwork or similar mechanism, and the movement of the upper carbon,actuated by gravity, is controlled by an annular clamp, which surrounds the rod carrying thecarbon. When the lamp is in operation, one side of this clamp is lifted by magnetic action ;this causes it to grasp and raise the rod, and thus separate the carbons. As the carbons burn away,the magnetic action <liminishes, and the clamp and rod move gradually downward, maintainingonly a proper separation of the carbons ; but when the tilted clamp touches the supporting floor from. 1 570 ELECTRICAL ENGINEERING. which it started, any farther downward movement releases the rod, and allows it to slide throughthe clamp, until tlie latter is again brought into action by the increased magnetism due to theshortened arc between the carbons. In continued operation, the normal position of the clamp is incontact with its lower support, the office of the controlling magnet being to regulate the sliding ofthe rod through it. If, however, the rod accidentally slides too far, it will automatically be raisedagain, and the carbon points maintained in proper relation. Each magnet helix is first wound witha few layers of coarse wire, through which the main portion of the current passes. Over this coarsewire is wound a very much greater length of fine wire, not shown, having its ends connected withthe terminals of the lamp, but in such a manner that the electric current shall pass through it, i
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectenginee, bookyear1879
