. Electrical world. so that the axle of the needle is in the direction of the wire. If thefrequency of the current in the wire is n (from which, of course,the slip of the motor can be easily determined, since n is the fre-quency corresponding to the slip), the magnet needle makes 60ttperiodic movements per minute, which may be counted. If themotor has a squirrel-cage armature this method can, of course, notbe used. In this case he applies the arrangement shown in Fig. FIG. 2. Connected to the shaft of the induction motor is the rod 6, gearedat its end to a disc, Z^, by which the revolution
. Electrical world. so that the axle of the needle is in the direction of the wire. If thefrequency of the current in the wire is n (from which, of course,the slip of the motor can be easily determined, since n is the fre-quency corresponding to the slip), the magnet needle makes 60ttperiodic movements per minute, which may be counted. If themotor has a squirrel-cage armature this method can, of course, notbe used. In this case he applies the arrangement shown in Fig. FIG. 2. Connected to the shaft of the induction motor is the rod 6, gearedat its end to a disc, Z^, by which the revolutions are counted. Thesame rod carries the commutator, U, consisting of a series of contactdiscs and two brushes, b and fr^. C^ is the dial which counts thenumber of impulses sent from the commutator, U, to the electro-magnet, E. There are three terminals, k, k^ and k^; k and k areused for voltages between 70 and 125, while k and k^ are used be-tween 125 and 200 volts. In the case of a high-voltage motor a smallauxiliary transformer is made use of. The commutator, U. servesfor sending periodic currents to the electromagnet. U consists ofseven contact discs, the first of which has an uninterrupted metallicSurface on which the brush, b. slides. The other contact discs have different numbers of insulating pieces inserted on therr surface, andthe brush, 6^, is connected to that contact disc which correspondsto the number of poles of the motor. The electromagnet, E, hasfou
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
