Read Online Wizard: The Life and Times of Nikola Tesla by Marc Seifer - Free Book Online
Authors: Marc Seifer
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in Italy, where they met Ferraris. 50 Purchased by George Westinghouse for $50,000, the system was installed in Great Barrington, Massachusetts, the following year by William Stanley, Westinghouse’s head engineer. The Gaulard-Gibbs invention, however, did not do away with the commutator, which was the express purpose of Tesla’s design.
In Ferraris’s published treatise on his independent discovery of a rotating magnetic field, he wrote, “This principle cannot be of any commercial importance as a motor.” After learning of Tesla’s work, Ferraris stated, “Tesla developed it much further than [I]…did.” 51
Bradley filed for a patent for an AC polyphase device on May 8, 1887 (no. 390,439) after nine Tesla AC patents had been granted. Haselwander, in the same year, utilized slip rings in place of commutators on DC Thomson-Houston equipment and also designed two- and three-phase windings on DC armatures. 52
The question of priority concerning Tesla’s invention was discussed by Silvanus P. Thompson, a physics professor in London, in his 1897 comprehensive text on AC motors. Thompson (no relationship to Elihu Thomson), considered at the time to be “perhaps the best known writer on electrical subjects now living,” said that Tesla’s work separated itself clearly from predecessors and contemporaries in his “discovery of a new method of electrical transmission of power [emphasis added].” 53
A question that remains unanswered was whether or not Tesla knew of Baily’s work. It is quite possible that he had read Baily’s paper, although no one at the time, including Baily, comprehended the importance of the research or understood how to turn it into a practical invention. 54 Tesla stated in the early 1890s, “I am aware that it is not new to produce the rotations of a motor by intermittently changing the poles of one of its elements…In such cases, however, I imply true alternating currents; and my invention consists in the discovery of the mode or method of utilizing such currents.” 55
A few years later, in a well-publicized case involving patent priorities on what came to be known as the “Tesla Alternating Current Polyphase System,” Judge Townsend of the U.S. Circuit Court of Connecticut noted that before Tesla’s invention and lecture to the American Institute of Electrical Engineers (AIEE) in 1888, there had been no AC motors; furthermore, no one attending the lecture recognized any priorities. Whereas Baily had dealt with “impractical abstractions, Tesla had created a workable product which initiated a revolution in the art.” 56 The Tesla patents were also sustained against individual cases involving Charles Bradley, Mons. Cabanellas and Dumesnil, William Stanley, and Elihu Thomson. 57
In citing a previous case on a similar issue, Judge Townsend responded to what today is called the “doctrine of obviousness”:
The apparent simplicity of a new device often leads an inexperienced person to think that it would have occurred to anyone familiar with the subject, but the decisive answer is that with dozens and perhaps hundreds of others laboring in the samefield, it had never occurred to anyone before [ Potta v. Creager, 155 U.S. 597]…Baily and the others [e.g., Bradley, Ferraris, Stanley] did not discover the Tesla invention; they were discussing electric light machines with commutators…Eminent electricians united in the view that by reason of reversals of direction and rapidity of alternations, an alternating current motor was impracticable, and the future belonged to the commutated continuous current…
It remained for the genius of Tesla to…transform the toy of Arago into an engine of power. 58
The discovery of how to effectively harness the rotating magnetic field was really only a fraction of Tesla’s creation. Before his invention, electricity could be pumped approximately one mile, and then only for illuminating dwellings. After Tesla, electrical power could be transmitted
In Ferraris’s published treatise on his independent discovery of a rotating magnetic field, he wrote, “This principle cannot be of any commercial importance as a motor.” After learning of Tesla’s work, Ferraris stated, “Tesla developed it much further than [I]…did.” 51
Bradley filed for a patent for an AC polyphase device on May 8, 1887 (no. 390,439) after nine Tesla AC patents had been granted. Haselwander, in the same year, utilized slip rings in place of commutators on DC Thomson-Houston equipment and also designed two- and three-phase windings on DC armatures. 52
The question of priority concerning Tesla’s invention was discussed by Silvanus P. Thompson, a physics professor in London, in his 1897 comprehensive text on AC motors. Thompson (no relationship to Elihu Thomson), considered at the time to be “perhaps the best known writer on electrical subjects now living,” said that Tesla’s work separated itself clearly from predecessors and contemporaries in his “discovery of a new method of electrical transmission of power [emphasis added].” 53
A question that remains unanswered was whether or not Tesla knew of Baily’s work. It is quite possible that he had read Baily’s paper, although no one at the time, including Baily, comprehended the importance of the research or understood how to turn it into a practical invention. 54 Tesla stated in the early 1890s, “I am aware that it is not new to produce the rotations of a motor by intermittently changing the poles of one of its elements…In such cases, however, I imply true alternating currents; and my invention consists in the discovery of the mode or method of utilizing such currents.” 55
A few years later, in a well-publicized case involving patent priorities on what came to be known as the “Tesla Alternating Current Polyphase System,” Judge Townsend of the U.S. Circuit Court of Connecticut noted that before Tesla’s invention and lecture to the American Institute of Electrical Engineers (AIEE) in 1888, there had been no AC motors; furthermore, no one attending the lecture recognized any priorities. Whereas Baily had dealt with “impractical abstractions, Tesla had created a workable product which initiated a revolution in the art.” 56 The Tesla patents were also sustained against individual cases involving Charles Bradley, Mons. Cabanellas and Dumesnil, William Stanley, and Elihu Thomson. 57
In citing a previous case on a similar issue, Judge Townsend responded to what today is called the “doctrine of obviousness”:
The apparent simplicity of a new device often leads an inexperienced person to think that it would have occurred to anyone familiar with the subject, but the decisive answer is that with dozens and perhaps hundreds of others laboring in the samefield, it had never occurred to anyone before [ Potta v. Creager, 155 U.S. 597]…Baily and the others [e.g., Bradley, Ferraris, Stanley] did not discover the Tesla invention; they were discussing electric light machines with commutators…Eminent electricians united in the view that by reason of reversals of direction and rapidity of alternations, an alternating current motor was impracticable, and the future belonged to the commutated continuous current…
It remained for the genius of Tesla to…transform the toy of Arago into an engine of power. 58
The discovery of how to effectively harness the rotating magnetic field was really only a fraction of Tesla’s creation. Before his invention, electricity could be pumped approximately one mile, and then only for illuminating dwellings. After Tesla, electrical power could be transmitted
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