The Electrician Volume 3-4 (Paperback)

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. 1884 Excerpt: ...allows a reduction of interest on 25 per cent, of the cost of conductors, and 50 per cent, of the running expenses due to heat waste, or a total of 75 per cent, of the interest on cost of conductors, a gain of 12.5 per cent. A further advantage to be derived from the reduction of the conductors to only half their original size, as compared with the reduction to one-fourth, is the lower temperature to which they will be exposed. With conductors reduced one-half in sectional area, the energy expended upon them, and therefore the heat developed, are only half the amount involved in either of the other arrangements; the thermal capacity of the wire being also half as great as in the two-wire system, the rise of temperature will be just the same. But if the conductors are reduced to one-fourth their original dimensions, while the quantity of heat generated in them remains the same, the rise of temperature will be four times as great as the two-wire plan. We submit the question then, whether Mr. Edison has not sacrificed a portion of the advantage legitimately belonging to his device by attempting too great a saving in the cost of conductors." In reply to the criticism of Professor Carhart, the author of the original article4, while admitting the justice of his correction, suggests that Professor Carhart has not reached the most economical result "for the reason that we have the interest on n conductors, but heat developed in only 2 of them." He proceeds to develop the solution of the problem mathematically, by assuming the size of the conductors in the 2-wire system to be such that the interest on their cost equals the cost of the heatenergy developed in them, from which he deduces the following table of comparative results: --In conclusion he says...