William Stanley, Jr. designed a practical induction coil system that varied alternating current (AC) voltage. His coil became the prototype for all future transformers and made practical the transmitting of electricity for consumer uses such as lighting.
Born in Brooklyn, New York, William Stanley attended private schools before enrolling at Yale University. He began to study law at age 21 but less than a semester later left school to look for a job in the emerging field of electricity. “Have had enough of this,” wrote the 21-year-old Yale freshman in 1879.
“Am going to New York.” With these words, William Stanley abandoned the career pattern that his father had laid out for him – college, law school, and membership in the family law firm – and set out instead on the more risky and exciting path of electrical invention. The decision marked the beginning of a productive career whose highlights included the invention of the modern type of transformer, and the creation of the business enterprise that was to become General Electric’s Pittsfield Works.
Stanley’s first job was as an electrician with one of the early manufacturers of telegraph keys and fire alarms. He then worked in a metal-plating establishment before joining Hiram Maxim, inventor of the machine gun and already a pioneer in the electrical industry. As Maxim’s assistant, Stanley directed one of the country’s first electrical installations, in a store on New York’s Fifth Avenue.
Stanley gave early evidence of his ability and enthusiasm. As his first employer, inventor Hiram S. Maxim described him: “Mr. Stanley was very young. He was also very tall and thin, but what he lacked in bulk, he made up for in activity. He was boiling over with enthusiasm. Nothing went fast enough for him.” This dynamism helped him gain an outstanding reputation in the early electrical industry.
In the 1880s every system for distributing electricity used direct current (DC). But DC transmission over long distances was impractical. Transmitting at low voltage required thick wires. Transmitting at high voltage was dangerous and could not be reduced for consumer uses such as lighting. It was known that alternating current (AC) voltage could be varied by use of induction coils, but no practical coil system had been invented.
Inventor and industrialist George Westinghouse learned of Stanley’s accomplishments and hired him as his chief engineer at his Pittsburgh factory. It was during this time that Stanley began work on the transformer. Actually the first practical AC transformer was developed by Frenchman Lucien Gaulard and Englishman John Gibbs; improvements were made at the Ganz company in Budapest. Westinghouse instructed Stanley and his assistants, Schmid and Shallenberger, to make tests to determine the commercial value of the Gaulard and Gibbs system.
He also arranged to have a number of the transformers and a Siemens alternating-current generator forwarded from England to Pittsburgh. Stanley, working under the direction of Westinghouse, devised a further improvement, which consisted in securing the enclosure of the coils by making the core of E-shaped plates, the central projections of each successive plate being alternately inserted through prewound coils from opposite sides, thus permitting separate winding and consequently the better insulation of the coils. This form was further improved by Albert Schmid, who extended the ends of the arms of the E to meet the central projection. When inserting these plates the extensions were temporarily bent upward, and upon being released each plate formed a closed magnetic circuit about the sides of the coils.
In 1885, ill health almost cut short his career – some say he worked himself too hard. But it proved a disguised blessing, because it necessitated a move to his family home, Great Barrington, Massachusetts. In those peaceful surroundings, he was able to develop some ideas he had suggested two years earlier to his employer, George Westinghouse (who helped finance Stanley’s lab) for a new type of transformer. This work resulted, on March 20, 1886, in the demonstration of a prototype system of high voltage transmission employing Stanley’s parallel connected transformer. This system was used by him to provide lighting for offices and stores on the town’s Main Street.
Stanley recieved a patent on his transformer: “Induction-Coil”, Patent No. 349,611. These various inventions and discoveries led up within a year to commercial production of transformers of high efficiency and excellent regulating qualities. The development was a fine engineering performance in speed and in quality. The most important single contribution was by Stanley.
He brought out the parallel connection in which the transformers are connected in parallel, across the constant-potential alternating-current system, instead of being arranged in series, as in the Gaulard and Gibbs connection. He obtained patents on the method, involving the construction of transformers in which the counter electromotive force generated in the primary coil of the transformer was practically equal to the electromotive force of the supply circuit.
This is obvious now, but in 1886, when the principles and characteristics of the alternating current were practically unknown, it was a wonderful invention, and revolutionary in character. On this invention Stanley’s fame largely rests. Of course Stanley did not discover or invent a theory of counter electromotive force before any one else had thought of it.
Such fundamental things seldom happen in invention. His claim to great and original merit rests on the discovery of a theory which was new to him and the use of it in making a structure of immense importance in the affairs of men. Briefly, all transformers now made are built upon practically the same principles as those that were developed in these early products of the Westinghouse Company.
Assisted by William Stanley, Westinghouse worked to refine the transformer design and build a practical AC power network. In 1886, Westinghouse and Stanley installed the first multiple-voltage AC power system in Great Barrington, Massachusetts. The network was driven by a hydropower generator that produced 500 volts AC. The voltage was stepped up to 3,000 volts for transmission, and then stepped back down to 100 volts to power electric lights.
In 1890 Stanley established the Stanley Electric Manufacturing Company in Pittsfield, Massachusetts, to make transformers and auxiliary electrical equipment as well as electrical appliances. To organize it, he joined forces with two talented associates: John J. Kelley, an outstanding designer of motors: and a former Stanley laboratory worker, Cummings C. Chesney.
The company was purchased by General Electric in 1903. Stanley also developed the alternating-current watt-hour meter, making it possible to measure electricity use with a high level of accuracy. Stanley with E. P. Thomson had also invented an incandescent lamp with a filament of carbonized silk. During his lifetime he was granted 129 patents covering a wide range of electric devices. William Stanley died on May 14, 1916.