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Homework Help: How does beakman's electric motor work?

  1. Apr 10, 2005 #1
    In class we made a beakman's electric motor using wire, a battery, and a magnet. I don't understand how the motor works though. Can someone explain it to me? I think it has something to do with the magnetic poles, but I am not sure. This site: fly.hiwaay.net/~palmer/motor.html has a diagram of the exact motor we made. Thanks!
    Last edited: Apr 10, 2005
  2. jcsd
  3. Apr 12, 2005 #2

    Andrew Mason

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    It works on an inefficient DC motor principle.

    In the Beakman motor, that black square you see is a magnet. The coil has to be closer to one pole of the magnet (I don't see how it would work if it is right in the middle equidistant from the magnet's poles). So if you use a bar magnet, you have to be closer to one end.

    The current (from battery connected to wire armature via little hook cradles) goes around the armature windings in a loop (circle). This generates a magnetic field around the wire and turns the loop into a magnet (say N pole on top, S on bottom). If the loop is nearer the S pole of the bar magnet the loop will rotate so the N pole moves toward the bar magnet and the S pole moves away, so the loop turns.

    However when the loop makes a 1/2 turn, the current is cut off (because the wire has insulation on the side that is now in contact with the cradle contact) but the loop continues its motion (inertia) until the part with no insulation moves into contact and the current flows again repeating the cycle. In a normal DC motor, at the 1/2 turn the current switches direction (using a commutator) flipping the N and S poles of the loop instead of shutting off the magnetic poles, so there is positive torque at all times instead of torque on only half of the cycle.

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