Nowadays, full of technologies and constant innovations, it is even difficult to imagine life away from electric motors and all the facilities they have brought, from the domestic daily to the industries. But if today it all seems as simple as having a blender, know that reaching this stage was a slow and gradual process. Continue reading to learn the history of the electric motor!
In 1600 the English scientist William Gilbert published a work describing the force of magnetic attraction. The first electrostatic machine was built in 1663, by the German Otto Guericke, and perfected in 1774 by the Swiss Martin Planta.
The Italian medical professor Aloiso Galvani noticed, in 1786, that when he touched the frogs’ thighs that were hanging on an iron grid with a scalpel, they presented a contraction, which he called “animal electricity”. Another Italian, Alessandro Volta, discovered that between two different metals, immersed in conductive liquid, an electrical tension arose.
In 1799 he developed a source of energy that he called the “Volta column”, which could supply electrical current. The Danish physicist Hans Christian Oersted, in 1820, found by chance that the magnetic needle of a compass was deflected from its north-south position when it passed close to a conductor in which electric current circulated. This observation was the first step towards the development of the electric motor.
The physicist and mathematician André-Marie Ampère, based on these and other studies and findings, built the first electromagnet. This device was fundamental for the invention of several devices, such as the telephone, the microphone, the loudspeaker and the telegraph. Then, Englishman Michael Faraday discovered, in 1831, electromagnetic induction.
In 1832 the Italian scientist S. Dal Negro built the first reciprocating alternating current machine. The following year, the Englishman W. Ritchie invented the commutator, building a small electric motor in which the coiled iron core revolved around a permanent magnet. To give a complete rotation, the polarity of the electromagnet was alternated every half turn, through the switch.
The first electric motor
German professor Moritz Hermann von Jacobi, in 1838, developed an electric motor and applied it to a motorboat. The practical application of electrical energy in mechanical work was thus proven. However, all the energy came from batteries, which were expensive and restricted in use. The concern, then, turned to the generation of low-cost electricity.
The Siemens era
In 1856, the electrical engineer Werner Siemens reported the success achieved in the construction of a magnetic current generator, with a double induced T. But this device could not generate enough energy to power domestic industries and equipment. The permanent magnets were restricted in action.
Only ten years later Siemens built a generator without a permanent magnet, proving that the voltage required for magnetism could be removed from the rotor winding itself, that is, that the machine could self-excite itself.
In 1879 Siemens & Halske presented the first electric locomotive, with a power of 2 kW. But the machine was costly and vulnerable in service, requiring the development of a cheaper, more robust and lower-maintenance engine.
1885: the Italian electrical engineer Galileu Ferraris built a two-phase alternating current motor.
1887: Yugoslavian Nicola Tesla presented a small prototype of a two-phase induction motor with a short-circuit rotor.
1889: the Russian electrical engineer Michael von Dolivo Dobrowolsky, from the AEG company in Berlin, persisting in the research of the alternating current motor, applied for a patent for a three-phase motor with a cage rotor. It was simple, quiet, had less maintenance and high security in operation.
We can see that scientists, physicists and other professionals not always connected to science contributed to the discovery of the electric motor, which accelerated global industrialization and radically transformed people’s way of life.
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