CHAPTER III.

The Tesla Rotating Magnetic Field.—Motors with ClosedConductors.—Synchronizing Motors.—Rotating FieldTransformers.

The best description that can be given of what he attempted,and succeeded in doing, with the rotating magnetic field, is to befound in Mr. Tesla’s brief paper explanatory of his rotary cur-rent, polyphase system, read before the American Institute ofElectrical Engineers, in Mew York, in May, 1888, under thetitle “ A Mew System of Alternate Current Motors and Trans-formers.” As a matter of fact, which a perusal of the paperwill establish, Mr. Tesla made no attempt in that paper to de-scribe all his work. It dealt iu reality with the few topics enu-merated in the caption of this chapter. Mr. Tesla’s reticencewas no doubt due largely to the fact that his action was gov-erned by the wishes of others with whom be was associated, butit may be worth mention that the compiler of this volume—whohad seen the motors running, and who was then chairman of theInstitute Committee on Papers and Meetings—had great diffi-culty iu inducing Mr. Tesla to give the Institute any paper at all.Mr. Tesla was overworked and ill, and manifested the greatestreluctance to an exhibition of his motors, but his objections wereat last overcome. The paper was written the night previous tothe meeting, in pencil, very hastily, and under the pressurejust mentioned.

In this paper casual reference was made to two special formsof motors not within the group to be considered. These twoforms were: 1. A motor with one of its circuits in series with atransformer, and the other in the secondary of the transformer.2. A motor having its armature circuit connected to the gener-ator, and the field coils closed upon themselves. The paper inits essence is as follows, dealing with a few leading features ofthe Tesla system, namely, the rotating magnetic field, motors