Who patented electric motor?
The first ELECTRIC MOTOR capable of practical application was patented by Thomas Davenport of Rutland. Vt. on 25 February 1837. Davenport put two 50 lb motors of his own dasign to work the same year, one for drilling holes up to + in diameter in iron and steel, the other for turning hardwood. Each incorporated an electromagnet and operated at a speed of 450 rpm. In 1839 he built a larger motor to drive a rotary printing-press, which he used to print the first electrical journal in the USA, The Electro-Magnet and Mechanics Intelligence, published 18 January 1840.
In Britain the first practical electric motors were built by Robert Davidson of Aberdeen in 1839. Prof. Forbes, also of Aberdeen, wrote an account of them in a letter to the Philosophical Magazine the same year:
… he has an arrangement by which with only two electro-magnets and less than on square foot of zinc surface, a lathe is driven with such velocity as to be capable of turning small articles, Second, he had another arrangement by which, with the same small extent of galvanic power, a small carriage is driven on which two persons were carried along a coarse wooden floor of a room.
The first use of electricity to provide mechanical power on a considerable scale for industrial purposes was made at the Paris factory of the Societe Gramme in, or shortly before, 1873. All the machinery was driven by a motor supplied with current from a Gramme dynamo.
The first miniature electric motors were made by Thomas Alva Edison at Menlo Park, N.J. in 1880 to drive an electric pen he had designed for producing punctured copying stencils. The motor measured 1 x 14- inch, and operated at approx. 4,000 rpm to drive a vibrating needle in the pen-holder that would pick out letters in punctured dots. It was powered by a minute two-cell battery. Edison’s electric pen provided a successful method of duplicating multiple copies of manuscripts before the typewriter stencil rendered it obsolete. Manufacture was undertaken by the Western Electric Co. and at least 60,000 miniature motors and pens were sold for use in banks and offices.
