This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1880 Excerpt: ... practice this cannot be done just as directed, because the freed armature, having the weight of the plate off it, would be instantly and powerfully attracted, and the current would have to be stopped to free it. The simplest way in which to lower the carbon plates for further consumption is to throw the coil at the ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1880 Excerpt: ... practice this cannot be done just as directed, because the freed armature, having the weight of the plate off it, would be instantly and powerfully attracted, and the current would have to be stopped to free it. The simplest way in which to lower the carbon plates for further consumption is to throw the coil at the required side out of circuit; and to do this it is only necessary to scrape the insulation of a little of the wire leading the current to the binding screw, and to give the bared wire a twist around the pinch screw at E. Thus the magnet will be powerless on that side, and the light will not be extinguished. The screw at E may then be slackened, and the plate tapped downwards a little. It is found that about-ji-th of an inch will suffice for 5 hours' work. In order to obviate the necessity to even thus far disturb the lamp, the pinch screw may be set "easy"--that is, not hard against the plate; and when it is required to lower the latter, a tap or two with any wooden handle will suffice. This lamp will burn without any attention, and quite steadily, for at the least 6 hours, and often for 12 hours. If it is looked to every 6 hours or thereabouts, and the plates tapped a little downwards, it will burn for periods ranging from 50 to 120 hours with plates of moderate size. It gives little resistance to the current, as the magnets are coiled with one layer of No. 10 wire only, and the size of the carbon plates permits of a very low resistance in that direction. There is, further, the advantage that the resistance of this lamp is almost constant, and does not vary, like Serrin's regulator, from perhaps 5 ohms to 10 ohms in a few hours. The resistance here is more constant than that obtained in Rapieffs lamp. There is no fear that the plates ...
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