Westinghouse Electric & Mfg. Co. v. New England Granite Co.

103 F. 951, 1900 U.S. App. LEXIS 5353
CourtDistrict Court, D. Connecticut
DecidedAugust 29, 1900
DocketNo. 919
StatusPublished
Cited by8 cases

This text of 103 F. 951 (Westinghouse Electric & Mfg. Co. v. New England Granite Co.) is published on Counsel Stack Legal Research, covering District Court, D. Connecticut primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Westinghouse Electric & Mfg. Co. v. New England Granite Co., 103 F. 951, 1900 U.S. App. LEXIS 5353 (D. Conn. 1900).

Opinion

TOWNSEND, District Judge.

Final hearing on bill and-answer raising questions of patentability and infringement of complainant’s three patents granted to Nikola Tesla May 1, 1888, namely, Nos. 381,968, 382,280, and 382,279. No. 381,968 is for an electro-magnetic motor. No. 382,280 is for the electrical transmission of power by the method of operation described in No. 381,968. Patent No. 382,279 is for a specific construction of motor embodying the invention of the other two patents. It is not claimed that the defendant Batterson has infringed, and as to him the bill may be dismissed. The patents in suit relate to the art of electrical transmission of power by the use of mechanically generated alternating electric currents. It is, of course, understood that the real nature of electricity is still unknown, and that the nomenclature used herein, such as “currents,” “flowing,” etc., are merely convenient technical terms to indicate certain known results. The electric current induced by a mechanical generator — a dynamo — is necessarily alternating in character; that is, alternating in direction, so that the current, acting, on an armature, [952]*952first tends to actuate it in one direction and then reverses said effect, and neutralizes such actuation. _Such a current flows uninterruptedly and regularly, but rises in intensity from zero to maximum, and falls from maximum to zero, and then repeats said variations in the opposite direction. Its curve of increase or decrease of strength is indicated by a wave line or sine curve. Every mechanically generated current is naturally and originally an alternating current. Formerly it was not considered practicable to use mechanically generated currents until their alternations were straightened out by means of conmutators, which reversed the direction of the current so as to make it flow continuously through the conductors. A current which is periodically reversed by a commutator which thus breaks the current between the changes in direction and taires off the current in sections, is known as a “reversed” or “alternated” current. This distinction between an alternating and an alternated current should be carefully noted. An alternating current continues to act in opposite directions as originally generated. An alternated current has been so reversed that the whole flows in one direction, and is then known as a “continuous” current. When so reversed by commutators as to become continuous, the current loses certain characteristics essential to its highest efficiency. Prior to the Tesla inventions, only reversed or alternated electric currents were used for the transmission of power. The application of this system for the transmission of power was limited, for various reasons; among others, because a large current could, not be safely used at sufficiently high pressure for long distances. On the other hand, the pure alternating current was practically, unlimited in volume and pressure, and a change of pressure could be economically effected by the use of a transformer. Prior to Tesla’s inventions, however, these rapid alternations of the alternating current prevented the motor from starting its revolution, and interfered with its continuing in operation, except when in synchronism with the generator. It was, therefore, impracticable for varying loads.

The problem which was presented to Nikola Tesla, and which he successfully solved, was, how to overcome the difficulties attendant, upon the use of the alternating currents so that their inherent vitality and úntrammeled energy might be utilized for the unlimited transmission of power. In an electric motor the tendency of the armature is always towards the pole or point of maximum magnetic intensity. If a loosely-pivoted or freely-moving magnetic bar or armature be suspended midway between two coils of insulated wire wound in opposite directions on a soft iron bar, and one of the coils is electrically energized, north and south poles will be formed at the ends of the soft iron bar, their location depending upon which coil is energized; but, if both coils be equally energized, the two poles will neutralize each other, and cause a resultant north pole midway between the coils. If, now, the current in one coil be made weaker than in the other, said pole will move towards the coil of greater electrical energy. The magnetic bar or armature will follow the shifting position of the pole, and by thus gradually varying the energy in the coils the. armature may be alternately caused to move from the pole of one coil along towards the pole of the other coil. The alternating current generated [953]*953by an electrical machine, as before stated, constantly varies from maximum intensity to zero in one direction, and then from zero to maximum intensity in the opposite direction. In ihe invent ion of the patents in suit Tesla availed himself of this characteristic feature of alternating currents in the following way: In constructing a motor lie arranged on an annular soft iron core two pairs of magnetizing colls, each pair at right angles to the o fcher, — that is, one coil of one pair at the top, and one at the bottom,- — and one coil of the other pair at each opposite side of said core, and mounted an armature in the center. Then, connecting them with an alternating current generator, he caused a current from one pole of said generator to pass through one pair of coils and a current from the other to pass through the other pair. If the cycles of alternating currents he regarded as divided into 3(JO degrees, then, as shown in the Tesla illustrations, they will have a relative displacement of 90 degrees. In such position the lines of magnetic force traversing the two coils will be at maximum in one while at minimum in the other. This relative displacement marks The differing phase or time relation of the two currents. The effect of passing two- equal currents through said coils would be to cause tbe pole of maximum intensity to pass midway between the poles of the respective pairs of coils. But the effect of the ordinary operation of the generator, as before explained, was to cause the current in each pair of coils to vary from zero to maximum and to zero, and then to shift in the opposite direction; the intensity of the current flowing to one pair of coils being at maximum, while that of the other was at zero, and one increasing while the other decreased, and the result being to shift said poles so as to make them travel entirely around said core.

Fifteen days after the issue of the patents in suit Tesla read before the American Institute of Electrical Engineers a paper entitled “A. New System of Alternate Current Motors and Transformers,” in which, inter alia, he said:

"The transmission of power has been almost entirely confined to the use of continuous currents, and notwithstanding that many efforts have lieen made to utilize alternate currents for this purpose, they have, up to the present, at least as far as known, failed to Rive the result desired. * * The subject which I now have the pleasure of bringing to your notice is a novel system of electric distribution, and transmission of power by means of alternate currents, affording peculiar advantages, particularly in the way of motors, which I am confident will at once establish the superior adaptability of these currents to the transmission of power, and will show that many results heretofore unattainable can be reached by their use; results which are very much •desired in the practical operation of such systems, and which cannot be accomplished by means of such continuous currents. Before going into a.

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Bluebook (online)
103 F. 951, 1900 U.S. App. LEXIS 5353, Counsel Stack Legal Research, https://law.counselstack.com/opinion/westinghouse-electric-mfg-co-v-new-england-granite-co-ctd-1900.