With his wife (Emily Davenport), and a colleague (Orange Smalley), he invented the electric motor and electric locomotive circa 1834. Thomas Davenport received the first patent on an electric machine in 1837.
Further Reading Frank Wicks. "The Blacksmith's Motor. Electricity, magnetism, and motion: A self-taught Vermonter pointed the direction for lighting the world." Mechanical Engineering, July 1999. Patent 132. http://www.tecsoc.org/pubs/history/2002/feb25b.htm