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Ac Motors

  1. May 16, 2010 #1
    Hi,I am new here^^17 years old...

    I got a little problem with understanding how simple alternating currents motors/AC Motors work...

    Anyone has a good Table or Figure??

    Magnetic problems:
    1)Whats the difference between inducing current and normal electric current??
    2)Whats the meaning of "Cutting the Magnetic Flux"
    3)Whats the good thing of cutting magnetic flux

    Sorry for asking so many questions at once...

    Please help me.
     
  2. jcsd
  3. May 16, 2010 #2
  4. May 16, 2010 #3
    The Wikipedia website overlooks an important class of single-phase induction motors sold from about ~1905 to after WW I; the repulsion-start induction motor, which had a special set of rotor conductors (in addition to the squirrel cage) attached to a commutator, which the brushes lifted off of when the rotor neared the running RPM. See attached photo of one in my garage (Century Motor, U. S. Pat. Off. date 1915) with a radial commutator. One nice feature is that the starting surge current is lower, and the starting torque is higher, than an equivalent HP capacitor-start induction motor.

    Bob S
     

    Attached Files:

  5. May 20, 2010 #4
    I have worked on similar "modern" single phase AC motors. One used a spring loaded "centrifugal" mechanism, to open a switch to the "starter winding" once the motor was at speed. (More current/torque for start-up).

    Is your motor doing the same thing for the same purpose?
     
  6. May 20, 2010 #5
    There are three types of single-phase ac induction motors with centrifugal starting switches; split-phase, capacitor-start, and repulsion-start. Both split phase and capacitor start are reversed by changing the wiring polarity of the starting coil. The repulsion-start motor is reversed by means of a lever to rotate the brush location. See the lever in my attachment photo above, to the left of the motor axle.

    Bob S
     
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