Nikola Tesla

“ Motors constructed and operated upon this principle maintain almost absolutely the same speed for all loads within their normal working limits, and in practice it will be observed that if the motor is suddenly overloaded to such an extent as to check its speed, the speed of the generator, if its motive power be not too great, is diminished synchronously with that of the motor. ”

“ It is obvious that a proper progressive shifting, or movement of the lines of force may be utilized to set up a movement or rotation of either element of the motor, the armature or the field magnet, and that if the currents directed through the several circuits of the motor are in the proper direction no commutator for the motor will be required. So, to avoid all the usual commutating appliances in the system, the motor circuits are connected directly with those of a suitable alternating current generator. ”

“ This invention comprises a new method and apparatus for effecting the transmission of power by electrical agency whereby many of the present objections are overcome and great economy and efficiency secured.
In the practice of this invention a motor is employed in which there are two or more independent energizing circuits through which are passed, in the manner hereinafter described, alternating, currents, which effect a progressive shifting of the magnetism or of the "lines of force" which, in accordance with well known theories, produces the action of the motor. ”

“ Such a solution primarily demands a uniformity of speed in the motor, irrespective of its load within its normal working limits. On the other hand, it is necessary to attain a greater economy of conversion than has heretofore existed, to construct cheaper, more reliable and simple apparatus, and such that all danger and disadvantages from the use of currents of high tension, which are necessary to an economical transmission, may be avoided. ”

“ Assuming the armature to be rotating in a certain direction following the movement of the shifting poles, then let the direction of the shifting be reversed which may be done by reversing the connections of one of the two energizing circuits. If it be borne in mind that in a dynamo-electric machine the energy developed is very nearly proportionate to the cube of the speed, it is evident that at such moment an extraordinary power is brought to play in reversing the motor. ”

“ By producing an alternating current each impulse of which involves a rise and fall of potential, the exact conditions of the generator are reproduced in the motor, and by such currents and the consequent production of resultant poles the progression of the poles will be continuous and not intermittent. ”

“ It is not new to produce the rotation of a motor by intermittently shifting the poles of one of its elements. This has been done by passing through independent energizing coils on one of the elements, the current from a battery or other source of direct or continuous currents, reversing such currents by suitable mechanical appliances so that they are directed through the coils in alternately opposite directions. ”

“ This plan is a very advantageous one, but it is characteristic of a motor so operated that if the field magnet be strongly energized by its coils and the circuits through the armature coils closed, assuming the generator to be running at a certain speed, the motor will not start but if the field be but slightly energized or in general in such condition that the magnetic influence of the armature preponderates in determining its magnetic condition, the motor will start and with sufficient current, will reach its normal or maximum speed. ”

“ It will be found if the fields of both the generator and motor be strongly energized, that starting the generator starts the motor, and that the speed of the motor is increased in synchronism with the generator. ”

“ Figure 15 is a diagramatic representation of a modified disposition of the invention. Figure 16 is a horizontal cross section of the motor. In this case a disk D, of magnetic metal preferably cut away at opposite edges as shown in dotted lines in the Figure, is mounted so as to turn freely inside two stationary coils N' N" placed at right angles to one another. The coils are preferably wound on a frame O of insulating material and their ends are connected to the fixed terminals T T T' T'. ”

“ The practical results of such a system, its economical advantages, and the mode of its construction and operation will be described more in detail by reference to the accompanying drawings and diagrams. ”