Essay on The Physics of an Electric Motor

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The Physics of an Electric Motor

An electric motor is a device used to convert electric energy into rotational kinetic energy. There are two different types of electric motors, and each has there own use. The different types are direct current and alternating current motors. Each of these motors will be analyzed in the following.

To understand how this motor works, we must understand the relationship between electricity, and magnetism or simply put electromagnetism. Direct electric current in a simple description: There are two requirements for current flow. The first is a source of electrical potential energy or EMF (electro motive force,). The second is a conductor that provides a complete loop to carry the current. The
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Magnetic fields are generated by current loops. Naturally occurring magnetism originates in the current loops at the atomic level. In short moving electric charges create magnetic fields. That is the principal that makes electromagnetism exist. When a coil of wire is passed through a magnetic field current is created in the wire. This shows the relationship between electric and magnetic fields.

“…a current-carrying wire in a magnetic field does experience a force. Because and electric current is a stream of charged particles, motion of the charge must be important. As bizarre as it seems, the magnetic force on a charged particle is zero unless the charge is moving!

In addition, the direction of the magnetic force is probably not the direction you would predict…the wire experiences a force in a direction perpendicular to the wire and perpendicular to the magnetic field. Thus, we expect a charged particle moving in a magnetic field to experience a force that is a right angle to its velocity and to the magnetic field.

The strength of the force depends on the charge q, the strength of the magnetic field B, the velocity v, and the angle between the field and the velocity. The magnetic force is maximum when the field and velocity are perpendicular, Fmax=qvB “ (Kirkpatrick\Wheeler Pg. 528) The direction of the magnetic field is determined by the direction of current flow. If you were to grab a current carrying wire, with your thumb

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