Introduction to Electric Motors
– An electric motor converts electrical energy into mechanical energy.
– Electric motors operate through the interaction between the motor’s magnetic field and electric current in a wire winding.
– Electric generators are mechanically identical to electric motors but operate in reverse, converting mechanical energy into electrical energy.
– Electric motors can be powered by direct current (DC) or alternating current (AC) sources.
– They can be classified based on power source type, construction, application, and type of motion output.
Applications and History of Electric Motors
– Electric motors are used in industrial fans, blowers, pumps, machine tools, household appliances, power tools, vehicles, and disk drives.
– Small motors can be found in electric watches.
– Electric motors can be used in reverse as generators to recover energy in applications like regenerative braking.
– They are used for ship propulsion, pipeline compression, and pumped-storage applications, with output exceeding 100 megawatts.
– Electric motors produce linear or rotary force (torque) to propel external mechanisms.
– Experimental electrostatic motors were investigated before modern electromagnetic motors.
– The invention of the electrochemical battery by Alessandro Volta in 1799 made persistent electric currents possible.
– Hans Christian Ørsted discovered the relationship between electric current and magnetic fields in 1820.
– Michael Faraday demonstrated the first rotary motion effect of electric current and magnetic field interaction in 1821.
– Ányos Jedlik demonstrated the first practical DC motor in 1828, containing the stator, rotor, and commutator.
– The first commutator DC electric motor capable of turning machinery was invented by William Sturgeon in 1832.
– Thomas Davenport built a commutator-type DC motor in 1837, but it was commercially unsuccessful.
– Moritz von Jacobi created the first real rotating electric motor in 1834, which set a world record.
– Antonio Pacinotti described the ring armature in 1864, leading to commercially successful DC motors.
– Zénobe Gramme reinvented Pacinotti’s design in 1871, leading to further advancements in DC motors.
– The reversibility of electric machines was discovered by Werner Siemens and announced in 1867.
– Gramme accidentally demonstrated the reversibility of electric machines at the 1873 Vienna World’s Fair.
– Advancements in electric motor technology led to the development of more powerful and efficient motors.
Advancements in Electric Motors
– Modern electric motors incorporate technologies like brushless designs, axial or radial flux configurations, and air or liquid cooling.
– Ongoing research and development aim to improve the performance and efficiency of electric motors.
DC Motors
– Friedrich von Hefner-Alteneck of Siemens & Halske introduced the drum rotor in 1872, improving machine efficiency.
– Siemens & Halske introduced the laminated rotor in 1873, reducing iron losses and increasing induced voltages.
– Jonas Wenström further increased efficiency by providing slots for the rotor winding in 1880.
– Frank Julian Sprague invented the first practical DC motor in 1886, revolutionizing industry.
AC Motors
– French physicist François Arago formulated the existence of rotating magnetic fields in 1824.
– Galileo Ferraris invented the first AC induction motor in 1885.
– Nikola Tesla independently invented his induction motor in 1887 and obtained a patent in 1888.
– George Westinghouse acquired rights to Ferraris’ and Tesla’s patents and developed practical AC induction motors.
– Mikhail Dolivo-Dobrovolsky invented the three-phase induction motor in 1889, which became widely used.
– Electric motor sales were estimated to be 800 million units in 2022, increasing by 10% annually.
– Electric motors consume approximately 50% of the world’s electricity.
– Electric motors have become essential in various industries and applications.
– Electric motors play a crucial role in the transition towards sustainable energy solutions. Source: https://en.wikipedia.org/wiki/Electric_motor
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An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor's shaft. An electric generator is mechanically identical to an electric motor, but operates in reverse, converting mechanical energy into electrical energy.
Electric motors can be powered by direct current (DC) sources, such as from batteries or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators.
Electric motors may be classified by considerations such as power source type, construction, application and type of motion output. They can be brushed or brushless, single-phase, two-phase, or three-phase, axial or radial flux, and may be air-cooled or liquid-cooled.
Standardized motors provide power for industrial use. The largest are used for ship propulsion, pipeline compression and pumped-storage applications, with output exceeding 100 megawatts.
Applications include industrial fans, blowers and pumps, machine tools, household appliances, power tools, vehicles, and disk drives. Small motors may be found in electric watches. In certain applications, such as in regenerative braking with traction motors, electric motors can be used in reverse as generators to recover energy that might otherwise be lost as heat and friction.
Electric motors produce linear or rotary force (torque) intended to propel some external mechanism. They are generally designed for continuous rotation, or for linear movement over a significant distance compared to its size. Solenoids also convert electrical power to mechanical motion, but over only a limited distance.
