Occult and Mysterious Powers
February 25, 1837: First American Patent for Electric Motor
With his wife Emily, and a colleague Orange Smalley, Thomas Davenport received the first American patent on an electric motor in 1837, U. S. Patent No. 132.
Thomas Davenport became an apprentice to a blacksmith at age 14 and later set up his own shop in Brandon Vermont. He loved books and acquired all the books he could find on electricity and magnetism.
There goes the horse
At age 29 Davenport visited the Penfield Iron Works at Ironville, New York. He was fascinated and impressed by the powerful commercial electromagnets used to lift up to 750 pounds of iron separating different purity’s of iron. Davenport decided he needed one of those magnets of his own.
So… he sold his brother’s horse (thanks Bro) and used his savings to buy an electromagnet. Once he had the magnet he took it apart and studied its construction.
An electric motor is a device that uses electricity to create mechanical force. Joseph Henry, an American scientist, had created some simple devices that made motion from his electromagnets, but the devices were inefficient and viewed as more of a whirligig novelty.
Davenport, building off Henry’s foundation, used his improved electromagnet with silk from his wife’s wedding dress as an insulating material and built an apparatus that used four electromagnets. He mounted two electromagnets to a pivot, and two others on fixed poles. He then used a battery attached to a commutator (a switching device) to supply current to the system. When he threw the switch the device rotated and thus created the “first” electric motor.
Davenport exhibited his invention one year later in 1835 in Springfield, Massachusetts. He constructed a model electric train that used the track to conduct power.
Trouble getting the patent
Davenport attempted to patent his device but was refused. The patent office officials had never patented an electric device before. Davenport returned home and received letters of recommendation from academics and scientists. He visited Rensselaer Polytechnic Institute, the nation’s first engineering school and obtained support. He traveled to Princeton, NJ where he met Joseph Henry, he also traveled to the University of Pennsylvania where he met Benjamin Franklin Bache. In 1837 Davenport was able to patent his invention (Patent # 132). He used his motor to operate a small car, this perhaps being the first electric car in history.
Davenport’s invention attracted the attention of the media. The New York Herald wrote “The occult and mysterious principle of magnetism is being displayed in all of its magnificence and energy as Mr. Davenport runs his wheel.”
Davenport’s motor was used later on by innovators like Edison to develop more advanced devices. When ran backwards Davenport’s motor generated power, and was one of the earliest DC dynamos.
He visualized the future as being full of large electric motors working for man. He returned home to Vermont broke and decided to write a book about the role of the electric motor in the future. He never finished his book and unfortunately died young and broke. The impact of his inventions and visions make him a significant if unsung part of the history of electricity.
The Basics – How an Electric Motor Works