ISBN: 9781130418286

RareBooksClub. Paperback. New. This item is printed on demand. Paperback. 504 pages. Dimensions: 9.7in. x 7.4in. x 1.0in.This historic book may have numerous typos and missing text. Pur… Plus…

RareBooksClub. Paperback. New. This item is printed on demand. Paperback. 504 pages. Dimensions: 9.7in. x 7.4in. x 1.0in.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. 1915 Excerpt: . . . within a reasonably short length of time will be of sufficient length and require sufficient air to load the motor to capacity. Electric motors are designed to operate at full load and under this condition they show the best performance in efficiency, power factor (in alternating-current motors), speed regulation, commutation (in direct-current motors), etc. Where a large number of motors are installed the cumulative effect of improper selection will be very noticeable, as the power bill will show. When the installation is alternating-current and the power is WAGNER SINGLE-PHASE MOTOR BELTED TO A SANITARY REFRIGERATING MACHINE J25-HORSEPOWER WESTINGHOUSE MOTORS DRIVING 65-TON WOLF AMMONIA COMPRESSORS IN AN ICE PLANT generated at the plant, it is especially desirable that all motors operate, as nearly as possible, at full load continuously. On fractional loads the power factor of induction motors decreases rapidly and causes the equipment to draw a wattless current from the generators, producing no work and dissipated in magnetizing the windings of the motor. This so-called wattless current may amount to 15 to 40 per cent or more of the total current generated, depending on the load, and it can thus be readily seen what effect the generation of an excessive amount of wattless current will have on the cost of power at the switchboard. In direct-current motor applications the effect of over-motoring is evidenced in the low operating efficiency of the equipment. Over-motoring may be likened to the use of several engines to haul a train of cars when one is amply sufficient. It represents an installation that is inefficient and that is an economic waste. Every dollar spent in unneeded motor capacity has to be paid for just the . . . This item ships from La Vergne,TN., RareBooksClub<