This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 edition. Excerpt: ...The method of determining the magnetic leakage coefficient of a dynamo having a single magnetic circuit is as follows: The armature of the machine is fixed so that it cannot turn and a temporary coil, A, Fig. 17, of insulated wire is wound lengthwise over the armature so as to enclose all of the flux that passes through the armature. Another coil, B, having the same number of turns as coil A, is wrapped around the field coil of the dynamo as near to the yoke as possible. A low reading voltmeter is arranged so as to be connected to coil A or coil B at will, by means of a double-pole double-throw switch. The field winding of the dynamo is connected through a suitable rheostat and switch to supply mains. The throw of the voltmeter is observed upon breaking the field circuit of the dynamo, first with the voltmeter connected to coil A and then with the voltmeter connected to coil B. These throws are proportional to Ia and Ie respectively, and therefore the ratio of the throws is equal to the magnetic leakage coefficient. Apparatus.--Any type of dynamo may be used in this experiment. Figure iya shows the two coils A and B properly placed upon a bipolar dynamo, and Fig. I "jb shows the arrangement of the two coils on a multipolar dynamo. Wind the two coils A and B and connect the voltmeter as specified above. It is well to connect a resistance box in circuit with the voltmeter so that by varying the resistance the voltmeter throw may be reduced to a readable value. Thq field winding is connected as specified above. Work to be done.--1. Determine the leakage coefficient of a machine having a single magnetic circuit: (a) for a field current about 50 per cent. above normal; (b) for normal field current; and (c) for 50 per cent. of normal field...