Nikola Tesla

“ The motor coils are generally of fine wire and the generator coils of coarser wire so as to produce a current of greater quantity and lower potential than the line current which is of relatively high potential to avoid loss in long transmission. A similar arrangement is to wind coils corresponding to those described on a ring or similar core and by means of a commutator of suitable kind to direct the current through the inducing coils successively so as to maintain a movement of the poles of the core and of the lines of force which set up the currents in the induced coils. ”

“ Without enumerating the objections to these systems in detail, it will suffice to say that the theory or the principle of the action or operation of these devices has aparently been so little understood that their proper construction and use has, up to the present time, been attended with various difficulties and great expense. Transformers are very liable to be injured and burnt out, and the means resorted to for curing this and other defects have invariably been at the expense of efficiency. ”

“ To divide the current from a single source whereby a number of lamps, motors or other translating devices may be independently controlled and operated by the same source or current, and in some cases to reduce a current of high potential in the main circuit to one of greater quantity and lower potential in the independent consumption circuit or circuits. ”

“ The combination with independent electric transmission circuits, of transformers consisting of annular or similar cores wound with primary and secondary coils, the opposite primary coil of each transformer being connected to one of the transmission circuits, an alternating current generator with independent induced or armature coils connected with the transmission circuit whereby alternating currents may be directed through the primary coils of the transformers in the order and manner herein described. ”

“ In lieu of these devices various forms of electro-dynamic induction machines, including the combined motors and generators, have been devised. For instance, a motor is constructed in accordance with well understood principles and on the same armature are wound induced coils which constitute the generator. ”

“ The Figure being a diagram of the converter and the generator with their proper electrical connections.
A is a core which is closed upon itself, that is to say, it is of an annular, cylindrical or equivalent form; and as the efficiency of the apparatus is largely increased by the subdivision of this core it is made of thin strips plates or wires of soft iron electrically insulated from one another as far as practicable. ”