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ELECTRIC MOTOR AND ITS IMPACT
Electric Motor and Its Impact
Jimmy Cisneros-Acosta
Columbus High School
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Abstract
The first commutator DC electric motor capable of turning machinery was invented by the
British scientist William Sturgeon in 1832. Even though, William Sturgeon was the first to make
the electric motor capable of moving machinery, the credit does not only belong to him. Brilliant
minds like Michael Faraday, Andrew Gordon, and André-Marie Ampère are also used in the
discovery of the electric motor. This derives from Ampere’s force law, which was a theoretical
principle behind the conversion of mechanical force by the interactions of an electric current and
a magnetic field. It was Faraday, who demonstrated this conversion of electrical energy into
mechanical energy by using a free-hanging wire dipped in a pool of mercury, on which a
permanent magnet was placed. This showed the current passing through the wire making it rotate
around the magnet. Most of the electrical appliances present today have some sort of electrical
motor. This discovery has opened a doorway to the production of most of our products today.
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Since the 1800’s, society has shown much improvement with technology. One of the key
components to many of our electronic appliances comes from the motor. There are countless
appliances that use the motor like cars, computers, clocks, washing machines, DVD players, and
so much more. The credit for the construction of the electric motor does not belong to one
person. It took a collection of great minds to come up with what we have today as a necessity in
our electronic devices. The motor itself is broken into two different types: the direct current (DC
motor) and the alternating current (AC Motor). Both motors have different utilities and uses.
In 1820, Andre-Marie Ampere discovered the Ampere’s force law – the principle that
explained mechanical force production by interactions of magnetic field and electric current. The
idea of a force coming outside of the wire instead of just through it came from Michael Faraday.
In 1821, he was able to demonstrate electromagnetic forces with a wire rotating around a
permanent magnet in a pool of mercury. Passing current through the wire, it rotated around
magnet demonstrating that the passing current raised circular magnetic field around wire (Verma
2014). From the experiments of Faraday, William Sturgeon invents the electromagnet, which are
coil of wires with an iron core to enhance the magnetic field. Ten years later, in 1831, Michael
Faraday discovers and investigates electromagnetic induction, which is the generation of an
electric current due to a varying magnetic field. Michael Faraday lays the foundation for the
development of the electric generator (Doppelbauer 2014). However, it is in 1832, that William
Sturgeon the first ever commutator DC electric motor. Throughout the centuries, the
development of the electric motor continued until its present day form. However, real electric
motors are much more complex than just the concept behind the magnetic force acting on a
current to produce torque. Still, understanding the basic principles behind the function of the
motor can help with calculations in torque.
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The function of an electric motor is to convert electrical energy to mechanical energy.
This involves rotating coils of wire which are driven by the magnetic force exerted by a magnetic
field on an electric current. If the current-carrying wire is bent into a loop, then the two sides of
the loop which are at right angles to the magnetic field will feel opposite forces. These opposite
forces acting on each other cause the coil to rotate which causes torque. There are key parts with
the electric motor such as the commutator, rotor, air gap, stator, and windings.
The concept of the DC motor is understood through polarity and how north and south
poles react to each other. Opposites attract, like North and South, while the same poles repel, like
North and North. When electric current is supplied from the commutator through the coil in a
magnetic field, the force acting upon it causes the production of torque which turns the DC
motor. The North on the coil attracts to the South of the external magnetic field and the same
applies to the South on the coil and the North of the external magnetic field. DC electric motors
work for conditions controlling the speed is essential. It is due to the factor that DC motors have
a steady and constant current. In order to have constant current and controlled speed, the
commutator reverses the current each half revolution. Since the force acting on the wire is
perpendicular to the magnetic field and the wire, the equation to find force would be: F=ILB.
The force would be equal to the current that is passing through the wire times the length of the
side of the wire facing the magnetic field times the magnetic field. Finding the torque for the DC
motor would be force times the lever arm. The concepts of the DC motor are carried somewhat
to the AC motor.
Similar to the DC motor, the AC motor uses the concept of electrical current passing
through a coil to generate torque. Since the current is alternating, the motor will run smoothly
only at the frequency of the sine wave. It is called a synchronous motor. More common is the
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induction motor, where electric current is induced in the rotating coils rather than supplied to
them directly. The drawback of using this kind of AC motor is that there has to be a high current
flowing through the rotating contacts. This can lead to sparking and heating that can shorten the
lifespan of the motor. Like the AC motor, the DC motor has its advantages and disadvantages.
For example, the DC electric motors are incapable of producing power over long periods of time.
Each motor works differently according to what the job is. AC motors are effective for systems
that are hard to start because they need a lot of power for this purpose. The three phase AC
motors, also called polyphase, are commonly found in industrial sector. The AC motors have a
high starting power built to transmit lower levels of overall power (Bandurkar 2007). Both
motors have different uses depending on the type of job.
The impact of the discovery of the electrical motor has been enormous. Almost every
electrical appliance, ranging from clocks to cars, uses a type of motor. Like the discovery of the
light bulb, the process of the electric motor has opened up the doorway to many inventions in
today’s society.
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References
Bandurkar, D. (2007, September 29). Understanding Electric Motors.Articlesbase.com.
Retrieved March 1, 2014, from http://www.articlesbase.com/technologyarticles/understanding-electric-motors-223036.htm
Doppelbauer, M. (n.d.). The invention of the electric motor 1800-1854. History -. Retrieved
March 1, 2014, from http://www.eti.kit.edu/english/1376.php
Electric Motors. (n.d.). Electric Motors. Retrieved March 1, 2014, from http://hyperphysics.phyastr.gsu.edu/hbase/magnetic/elemot.html
Electric motors and generators. (n.d.).Electric motors and generators. Retrieved March 1, 2014,
from http://www.animations.physics.unsw.edu.a
Verma, S. (n.d.). Invention Story of Electric Motor. EngineersGarage. Retrieved March 1, 2014,
from http://www.engineersgarage.com/invention-stories/electric-motor-history