The invention of the electric motor 1800-1854

Michael Faraday, the recipient of the letter on 26 July 1832. publishes it immediately. For the first time a rotating electric machine is described in public.

The device is presented publicly in September 1832 at a meeting of the Académie des Sciences. His description is printed already in the July issue of the Annales de Chimie.

Pixii improved his device in the same year by adding a switching device. He can now produce a pulsating direct current.

Ritchie is therefore generally regarded as the inventor of the commutator.

At the end of his article Ritchie describes how he was able to rotate an electric magnet by utilization of the magnetic field of the earth. He could raise a weight of several ounces (50-100 grams). The commutation was performed by two wire ends, which ran into two semicircular troughs of mercury.

Heinrich Friedrich Emil Lenz (German) found the "law of reciprocity of the magneto-electric and electromagnetic phenomena", i.e. the reversibility of electric generator and motor.

His scientific text is recited at the end of 1833 at the St. Petersburg Academy of Sciences and published in 1834 in Poggendorff's Annalen der Physik und Chemie. His ideas are slowly becoming commonplace, especially in 1838 after several reports of successful reversal experiments.

Sometimes it is claimed that the reversal principle was discovered in 1861 by the Italian Pacinotti or even only in 1873 by chance at the Vienna World Exhibition. Both claims are false. Emil Lenz widely reported already in 1838 in Poggendorff's Annalen der Physik und Chemie how he used a Pixii generator as a motor.

His device corresponds to a metronome (similar to Henry's and Dal Negro's constructions), acting on the pendulum with two electromagnets. Rotary motion is generated via a piston rod.

A replica of the device is now on display in the Museo Galileo in Florence.

He turns to the construction of an electric motor, which he completes in May 1834. His motor lifts a weight of 10 to 12 pounds with a speed of one foot per second, which is equivalent to about 15 watts of mechanical power.
In November 1834, he sends a report to the Academy of Sciences in Paris and publishes a detailed scientific memoir in the spring of 1835. This paper later earns him an honorary doctorate from the Faculty of the University of Königsberg. His text is divided into 23 sections and was expanded in 1837 with a further 15 sections.

Jacobi expressly claimed in the memorandum of 1835 that he was not the sole inventor of the electromagnetic motor. He indicates the priority of the inventions of Botto and Dal Negro.

However, Jacobi is undoubtedly the first to create a usable rotating electric motor.

A fully functional replica of his engine is displayed at the Institute of Electric Engineering (ETI) of the Karlsruhe Institute of Technology (KIT) in the Engelbert-Arnold-Strasse 5 (Building 11.10) in Karlsruhe, Germany.

In July 1834 the two men create their first rotary machine. They improve the device in several steps before they publicly demonstrate it in December 1834 for the first time.

In the following year Davenport separates from Smalley. 

In the summer of 1835 Davenport travels to Washington, D.C., to demonstrate his machine before the patent office and have it registered. Due to lack of money, however, he has to return home without success.

He admits to being inspired by the electro-magnetic machine (generator) by Joseph Saxton, which is on display in a public gallery in London since August 1833.

Watkins can be counted among the first who understood the principle of reversal of motor and generator.

Stratingh and Becker publish a report of their success in the same year. Stratingh knew the work of Jacobi and wanted to build a real electric car in 1840, which he never succeeded.

Wagner holds his construction a secret and so there are reports on the demonstration, but no drawings of the machine. In subsequent years, Wagner developes his engine further and publicly demonstrates improved versions.

His model motor is now on display in the Smithsonian Institute in Washington, DC.

Davenport's patented design uses four rotating electromagnets that are switched by a commutator, and ring-shaped fixed permanent magnets made of soft iron.

An improved motor, which he presents in August 1837, has 6 ​​inches in diameter, rotates at about 1,000 revolutions per minute and can lift a 200 pound weight one foot in one minute. This corresponds to a power of 4.5 W.

Davenport continuously improved his designs in the following years.

Together with Edwin Williams of New York and his partner Ransom Cook, Davenport forms a joint capital stock association on March 3, 1837. However, Williams fails to sell enough of the stocks and the whole undertaking collapses just one year later.

On 13 September 1838, Jacobi demonstrates for the first time on the river Neva an about 8 m long, electrically powered boat with paddle wheels.

The zinc batteries have 320 pairs of plates and weighed 200 kg. They are placed along the two side walls of the vessel. The motor produces between 1/5 and 1/4 hp power (300 W), the boat travels with 2,5 km / h over a 7.5 km long route. It can carry more than a dozen passengers. Jacobi drives around for days on the river Neva. Contemporary newspaper articles state that after two to three months of operation the zinc consumption was 24 pounds.

Over the next 20 years, Page is researching to find better, more powerful machines. His engines were sold via catalog in the U.S. and reached a high level of public awareness.

In early years, many inventors of electric motors mimic steam engines with an oscillating (reciprocating) piston. Page also builds such a machine (see right), but then turns to rotating devices.

In October 1841 Jacobi demonstrates once again a further improved motor, which, however, is only slightly superior to the model from 1839. This is the last electric motor Jacobi ever builds. He now turns to the theory of electric motors and later moves on to other electric phenomena.

In 1839 Davidson manages the construction of the first electrically powered car.

In September 1842, he makes trial runs with a 5-ton, 4.8 m long locomotive on the railway line from Edinburgh to Glasgow. Its engine makes about 1 hp (0.74 kW) and reaches a speed of 4 mph (6.4 km / h).