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Frank J. Sprague
Frank Julian Sprague (July 25, 1857 – October 25, 1934) was an American inventor who contributed to the development of the electric motor, electric railways, and electric elevators. His contributions were especially important in promoting urban development by increasing the size cities could reasonably attain (through better transportation) and by allowing greater concentration of business in commercial sections (through use of electric elevators in skyscrapers). He became known as the "father of electric traction". Demonstrating an aptitude for science and mathematics, Sprague secured an appointment to the U.S. Naval Academy in 1874 and, after graduation in 1878 and 2 years at sea, resigned to pursue his career in electrical engineering.
Sprague was born in Milford, Connecticut, in 1857 to David Cummings Sprague and Frances Julia King Sprague, a school teacher His mother died when he was ten, and was sent by his father to live with an aunt in New York. He attended Drury High School in North Adams, Massachusetts, and excelled in mathematics. After graduating high school, Sprague went to Springfield, Massachusetts, to take an entrance exam for West Point, but somehow unexpectedly was taking the four day entrance exam for the United States Naval Academy in Annapolis, Maryland. He got the highest score (twelve others took the exam), and to go to the school he needed to borrow money. A local contractor and a bank loaned him four thousand dollars, and he travelled to Maryland. There, he graduated seventh (out of thirty-six) in the class of 1878.
He was commissioned as an ensign in the United States Navy. During his ensuing naval service, he first served on the USS Richmond, then the USS Minnesota. While in Asia, Sprague wrote stories he filed for the Boston Herald.[page needed] While his ship was in Newport, Rhode Island, in 1881, Sprague invented the inverted type of dynamo. After he was transferred to the USS Lancaster, the flagship of the European Squadron, he installed the first electric call-bell system on a United States Navy ship. Sprague took leave to attend the International Exposition of Electricity of 1881 in Paris and the Crystal Palace Exhibition in Sydenham, England, in 1882, where he was on the jury of awards for gas engines, dynamos and lamps.
In 1883, Edward H. Johnson, a business associate of Thomas Edison, persuaded Sprague to resign his naval commission to work for Edison. Sprague, who began at a salary of $2,500, was neither happy with his salary nor his assignments. Sprague wanted to focus on motors, while motors bored Edison, who was consumed in making his incandescent lighting work. Edison sent Sprague to run the construction departments where Edison had built central power stations for his lighting systems in Sunbury, Pennsylvania, and Brockton, Massachusetts.
Sprague did important work for Edison, including correcting Edison's system of mains and feeders for central station distribution.
In 1884, he decided his interests in the exploitation of electricity lay elsewhere, and he left Edison to found the Sprague Electric Railway & Motor Company.
By 1886, Sprague's company had introduced two important inventions: a constant-speed, non-sparking motor with fixed brushes, and regenerative braking, a method of braking that uses the drive motor to return power to the main supply system. His motor was the first to maintain constant speed under varying load. It was immediately popular and was endorsed by Edison as the only practical electric motor available. His regenerative braking system was important in the development of the electric train and the electric elevator.
Sprague's inventions included several improvements to designs for systems of electric streetcars collecting electricity from overhead lines. He improved designs for a spring-loaded trolley pole that had been developed in 1885 by Charles Van Depoele, devised a greatly improved mounting for streetcar motors and better gear designs, and proved that regenerative braking was practical. After testing his trolley system in late 1887 and early 1888, Sprague installed the first successful large electric street railway system – the Richmond Union Passenger Railway in Richmond, Virginia, which began passenger operation on February 2, 1888. Long a transportation obstacle, the hills of Richmond included grades of over 10%, and were an excellent proving ground for acceptance of his new technology in other cities, in contrast to the cable cars which climbed the steepest grades of Nob Hill in San Francisco at the time.
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Frank J. Sprague
Frank Julian Sprague (July 25, 1857 – October 25, 1934) was an American inventor who contributed to the development of the electric motor, electric railways, and electric elevators. His contributions were especially important in promoting urban development by increasing the size cities could reasonably attain (through better transportation) and by allowing greater concentration of business in commercial sections (through use of electric elevators in skyscrapers). He became known as the "father of electric traction". Demonstrating an aptitude for science and mathematics, Sprague secured an appointment to the U.S. Naval Academy in 1874 and, after graduation in 1878 and 2 years at sea, resigned to pursue his career in electrical engineering.
Sprague was born in Milford, Connecticut, in 1857 to David Cummings Sprague and Frances Julia King Sprague, a school teacher His mother died when he was ten, and was sent by his father to live with an aunt in New York. He attended Drury High School in North Adams, Massachusetts, and excelled in mathematics. After graduating high school, Sprague went to Springfield, Massachusetts, to take an entrance exam for West Point, but somehow unexpectedly was taking the four day entrance exam for the United States Naval Academy in Annapolis, Maryland. He got the highest score (twelve others took the exam), and to go to the school he needed to borrow money. A local contractor and a bank loaned him four thousand dollars, and he travelled to Maryland. There, he graduated seventh (out of thirty-six) in the class of 1878.
He was commissioned as an ensign in the United States Navy. During his ensuing naval service, he first served on the USS Richmond, then the USS Minnesota. While in Asia, Sprague wrote stories he filed for the Boston Herald.[page needed] While his ship was in Newport, Rhode Island, in 1881, Sprague invented the inverted type of dynamo. After he was transferred to the USS Lancaster, the flagship of the European Squadron, he installed the first electric call-bell system on a United States Navy ship. Sprague took leave to attend the International Exposition of Electricity of 1881 in Paris and the Crystal Palace Exhibition in Sydenham, England, in 1882, where he was on the jury of awards for gas engines, dynamos and lamps.
In 1883, Edward H. Johnson, a business associate of Thomas Edison, persuaded Sprague to resign his naval commission to work for Edison. Sprague, who began at a salary of $2,500, was neither happy with his salary nor his assignments. Sprague wanted to focus on motors, while motors bored Edison, who was consumed in making his incandescent lighting work. Edison sent Sprague to run the construction departments where Edison had built central power stations for his lighting systems in Sunbury, Pennsylvania, and Brockton, Massachusetts.
Sprague did important work for Edison, including correcting Edison's system of mains and feeders for central station distribution.
In 1884, he decided his interests in the exploitation of electricity lay elsewhere, and he left Edison to found the Sprague Electric Railway & Motor Company.
By 1886, Sprague's company had introduced two important inventions: a constant-speed, non-sparking motor with fixed brushes, and regenerative braking, a method of braking that uses the drive motor to return power to the main supply system. His motor was the first to maintain constant speed under varying load. It was immediately popular and was endorsed by Edison as the only practical electric motor available. His regenerative braking system was important in the development of the electric train and the electric elevator.
Sprague's inventions included several improvements to designs for systems of electric streetcars collecting electricity from overhead lines. He improved designs for a spring-loaded trolley pole that had been developed in 1885 by Charles Van Depoele, devised a greatly improved mounting for streetcar motors and better gear designs, and proved that regenerative braking was practical. After testing his trolley system in late 1887 and early 1888, Sprague installed the first successful large electric street railway system – the Richmond Union Passenger Railway in Richmond, Virginia, which began passenger operation on February 2, 1888. Long a transportation obstacle, the hills of Richmond included grades of over 10%, and were an excellent proving ground for acceptance of his new technology in other cities, in contrast to the cable cars which climbed the steepest grades of Nob Hill in San Francisco at the time.