Electric motors are a kind of machine that serves
the purpose of converting electrical energy into mechanical energy (such
that can be used in a mechanical machine to turn cogs or levers etc).
Electric motors normally operate through the interaction of
magnetic fields and conductors carrying currents in order to generate force, while some others use alternate methods of action such as electrostatic forces. The opposite use - of creating electrical energy from mechanical energy, is conversely caused by an alternator, a generator or a dynamo. Lots of types of electric motors can run as generators however and vice versa - for instance a starter/generator used in a gas turbine or traction motor in vehicles often perform both of these tasks through a single unit.
magnetic fields and conductors carrying currents in order to generate force, while some others use alternate methods of action such as electrostatic forces. The opposite use - of creating electrical energy from mechanical energy, is conversely caused by an alternator, a generator or a dynamo. Lots of types of electric motors can run as generators however and vice versa - for instance a starter/generator used in a gas turbine or traction motor in vehicles often perform both of these tasks through a single unit.
Electrical motors are found in a huge range of
applications and are a crucial component of almost any mechanical device
that it powered electrically as well as many smaller appliances for use
around the home. These include industrial fans, pumps, blowers, hair
dryers, computers, power tools, motors, cars, even wristwatches. With
something like a computer you might not at first see how they are
required to use electric motors - however when you think of how a disk
drive works; by rapidly rotating the disk and reading the data off of it
as this happens, it becomes apparent. The largest electrical motors are
used for the propulsion of large ships and sometimes the rotor blades
of air-born vehicles. They are also often used as pipeline compressors
and these huge electric motors have ratings of millions of watts.
Electrical motors can be classified in a number of different ways -
through the source of their power, through their design and
construction, through their use within a mechanism, or by the type of
motion they give (normally rotary).
The principles of how
mechanical force could be created by the interactions of magnetic files
and electric current has been known as early as 1821 which allowed for
the construction of the first such motors. Following this, electric
motors of increasing efficiency were constructed through the 19th
century. In order to keep up with this demand it was necessary for
larger electrical generators and electrical distribution methods - so
that the motor has thereby contributed so much of industry and
development.
Some devices are similar to electric motors but are
not referred to as such, for instance magnetic solenoids and
loudspeakers. A loudspeaker fits the criteria of using electrical energy
in order to generate some mechanical movement, but this is normally
referred to as a transducer. Here the mechanical movement is not the end
result of that particular unit - but rather the sound generated as a
result.
It is possible also to power motors by other means - for
example by using steam as was used in old steam trains, or by using
petroleum or other fossil fuels. These types of motor however are not as
desirable as electrical motors as they are more expensive to run, and
as they create fuel emissions as a by-product that is harmful to our
health and to the atmosphere.
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