POLYPHASE CURRENTS.

39

supplies the current that maintains the field of force. In theusual construction of these machines the armature-conductor l iscarried by a suitable frame, so as to be rotated in face of themagnets j j, or between these magnets and another similar setin front of them. The magnets are energized so as to be of al"ternately opposite polarity throughout the series, so that as theconductor c is rotated the current impulses combine or areadded to one another, those produced by the conductor in anygiven position being all in the same direction. To adapt sucha machine to his system, Mr. Tesla adds a second set of inducedconductors m, in all respects similar to the first, but so placedin reference to it that the currents produced in each will differby a quarter-phase. "With such relations it is evident that as thecurrent decreases in conductor l it increases in conductor m, aridconversely, and that any of the forms of Tesla motor inventedfor use in this system may be operated by such a generator.

Fig. 31 is intended to show a motor corresponding to the ma-chine in Fig. 30. The construction of the motor is identical withthat of the generator, and if coupled thereto it will run syn-chronously therewith, j' j' are the field-magnets, and k' thecoils thereon, i/ is one of the armature-conductors and m' theother. .

Fig. 32 shows in diagram other forms of machine. The gene-rator n in this case is shown as consisting of a stationary ring o,wound with twenty-four coils p p', alternate coils being connectedin series in two circuits. Within this ring is a disc or drum q,with projections q' wound with energizing-coils included in cir-cuit. with a generator k. By driving this disc or cylinder alter-nating currents are produced in the coils p and p', which arecarried off to run the several motors.

The motors are composed of a ring or annular field-magnet s,wound with two sets of energizing-coils t t', and armatures u,having projections u' wound with coils v, all connected in seriesin a closed circuit or each closed independently on itself.

Suppose the twelve generator-coils p are wound alternately inopposite directions, so that any two adjacent coils of the same settend to produce a free pole in the ring o between them and thetwelve coils p' to be similarly wound. A single revolution ofthe disc or cylinder q, the twelve polar projections of which areof opposite polarity, will therefore produce twelve current im-pulses in each of the circuits w w'. Hence the motor x, which