POLYPHASE CURRENTS.

13

atively weaker poles n h in Fig. 4«. Tlie current in the coil C!

is of the same strength, but opposite direction. Its effect is,therefore, to produce upon the ring the poles n x as indicated,and a polarity, n s, results, the poles now being shifted three-eighths of the periphery of the ring.

In Fig. 5 one half of one revolution of the armature is com-

Fra. 5a.

pleted, and the resulting magnetic condition of the ring is indi-cated in Fig. 5 a. Now the current in coil o is nil, while the coilCj yields its maximum current, which is of the same direction aspreviously ; the magnetizing effect is, therefore, due to the coils,c, alone, and, referring to Fig. 5 a, it will be observed thatthe poles n s are shifted one half of the circumference of thering. During the next half revolution the operations are repeated,as represented in the Figs, (i to 8 a.

A reference to the diagrams will make it clear that during one

Fig. 6a.

revolution of the armature the poles of the ring are shifted oncearound its periphery, and, each revolution producing like effects,a rapid whirling of the poles in harmony with the rotation of thearmature is the result. If the connections of either one of thecircuits in the ring are reversed, the shifting of the poles is madeto progress in the opposite direction, but the operation is identi-