Harry Ward Leonard was born at Cincinnati, Ohio, the son of Ezra George Leonard, a merchant, and Henrietta Dana (Ward). He was a descendant of Solomon Leonard, a native of Monmouthshire, England, who emigrated to Leyden, Holland, and thence, not long after 1630, to Massachusetts, where he lived successively at Plymouth, Duxbury, and Bridgewater. General Artemas Ward was an ancestor.
Leonard attended grammar and high school at Cincinnati, and entered the Massachusetts Institute of Technology in 1879. He graduated in 1883 with the degree of electrical engineer.
In 1883 Leonard became associated with Thomas A. Edison as one of a staff of four employed by him to introduce the central-station system into the major cities of the country. When only twenty-six (1888), he became superintendent of the Western Electric Light Company at Chicago, and the next year was head of the firm of Leonard & Izard of that city, one of the first organizations in the United States to engage in central-station and electric-railway construction. In 1889 the firm was purchased by the Edison General Electric Company and Leonard became general manager for the United States and Canada of the light and power departments of the combined Edison interests. Resigning this position in 1894 he established a business of his own at Bronxville, New York, the Ward Leonard Electric Company, for the manufacture of electrical equipment, principally of his own invention.
In 1889 he patented the first electric train-lighting system (patents 405895, 405896, 405897), the elements of which are in use today. He had this system in operation on two trains between Chicago and Milwaukee in 1888. The best-known of his inventions is the Ward Leonard system of motor control (patent 463802, November 24, 1891, and many others), which provides a method of varying the speed of direct-current motors over a wide range without the use of a starting resistance, by applying a variable voltage to the motor armature. This system not only furnishes a very flexible and rapid control of heavy machinery, but also eliminates power loss in rheostats. It is estimated that fifteen percent, of the cost of rolling steel has been saved by replacing steam engines with electric motors equipped with the Ward Leonard system.
An electric elevator-control device (patent 468100, February 2, 1892) used by the Otis Elevator Company on the first electric elevators installed in the New York Athletic Club and the Times Building, New York City, the double-arm circuit breaker (patent 705102, July 22, 1902), a system of multiple voltage motor control (patent 478344, July 5, 1892), were important inventions of his and were incorporated by license rights in equipment manufactured by most of the leading electrical firms of the country. Other inventions of interest for which he was responsible are a system of regenerative braking for railroad trains and mine hoists, an incandescent-lamp socket, the "compound controller" for machine tool motors, and the fourspeed-change gear that was used on several of the higher-priced automobiles.
Leonard was interested also in the electric lighting and starting of automobiles, and designed one of the first of the simple and efficient systems of the modern type. He contributed many articles to the technical press, and papers and addresses of his appear in the Transactions of the American Institute of Electrical Engineers. He was a fellow, a vice-president (1893 - 1895), and a manager (1890 - 1893) of this Institute. He was president of the Inventor's Guild (1913 - 1914), which was one of his hobbies, as was also the development of the village of Bronxville, New York, of which he was president. He died suddenly while attending the annual dinner of the American Institute of Electrical Engineers in New York.
Leonard was best known for his invention, the Ward Leonard motor control system. Equipment based on this invention remained in service into the 21st century. He was the founder of the Ward Leonard Electric Company. He was granted patents for more than 100 inventions of electrical distribution and control systems and related equipment. In 1903 Leonard received the John Scott Medal award of the Franklin Institute for his contributions to electrical development.
Member of the American Institute of Electrical Engineers
In 1895 Leonard married Carolyn Good of New York; there were no children.
