Today in History – April 24, 1877 – Brush patents first dynamo or electric generator. The dynamo was a concept that had been built earlier by Faraday, Henry and Pacinotti and Gramme and concurrently by Edison, but Brush’s more efficient dynamo got the U.S. patent. Brush’s dynamo eventually became the workhorse of the electric power generating industry. Charles Brush developed his first dynamo in the summer of 1876 while “vacationing” at his old home, Walnut Hills Farm. He used a horse-drawn treadmill to power the dynamo and generate electricity. On April 24, 1877 he was awarded U.S. Patent No. 189 997, “Improvement in Magneto-Electric Machines”.

In addition to its importance in electric power generation, the dynamo made commercial lighting viable by providing an economic and efficient source of electricity. Brush designed and developed the electric arc lighting system that was used extensively throughout the United States and abroad during the 1880’s for commercial and street lighting. The arc light preceded Edison’s incandescent light bulb. The Brush Electric company, headquartered in Cleveland, Ohio, was sold in 1889 and merged with Edison General Electric in 1892 to form the General Electric Company.

The dynamo also enabled the development of electric motors that are used today in everything from air conditioners to consumer electronics. The average new automobile in the U.S. has over 30 electric motors in it, to operate everything from the electric starter to the power windows. The energy consumed by electric motors represents the single largest use of power in the United States.

For more information see the Engineering Pathway’s educational resources on Charles Brush and on electric motors. For related curricular resources, visit the Electrical Engineering Education or the Mechanical Engineering Education disciplinary communities.