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Can anyone describe in the simplest way possible how electric motors/electric...

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sasuke24 | Student, Undergraduate | (Level 2) Honors

Posted January 21, 2013 at 6:04 PM via web

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Can anyone describe in the simplest way possible how electric motors/electric generators work with respect to electromagnetism.Thanks in advance!  

Diagrams if possible would be much appreciated. 

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valentin68 | College Teacher | (Level 3) Associate Educator

Posted September 18, 2013 at 1:37 PM (Answer #1)

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For a diagram that works for both cases see the figure below.

A motor like a generator is composed of two parts, a stator that creates an external magnetic field (B in the figure) which is constant over time and a rotor that is made of a coil.

In the case of a motor, the the coil is supplied with a current I from an external voltage source. This current interacts with the field B and generates a force `F = I*(B xx L)` that rotates the coil.

In the case of a generator, the coil rotates in the field B because of an external applied torque (or equivalent said, force). Thus the surface of the coil that is intersected by the field B variates over time, hence the total flux of the field B through the surface S variates over time `Phi=B**S =B*S*cos(alpha)` , therefore there will be an induced voltage (or equivalent said, current) in the coil.

`U_("ind") = -(d(Phi))/dt`

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