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AC induction motor reverse 3 phase

  1. Sep 6, 2011 #1
    What happens if an big AC induction motor is running with full load an your suddenly reverse the 3 phase?
  2. jcsd
  3. Sep 6, 2011 #2
    Immediately after phase reversal, the motor will act like a generator and send power back to the source, and in doing so will heavily retard. As soon as it attain 0 speed it start rotating on the other direction. It would be like a regenerative Braking followed by direction reversal.
  4. Sep 6, 2011 #3
    Also as you swap the terminals you are likely to draw an arc due to the regenerating nature of the motor.
  5. Sep 6, 2011 #4
    I assume that you mean that you swap two phases over, thus reversing the direction of rotation of the motor, in a James Bond world the motor would try to turn backwards rip itself to pieces and start a chain reaction that ended with the bad guy's secret headquarters blowing up, in a real more prosaic world the motor overloads would trip, and the stand-by fan / pump would start automatically.
  6. Sep 6, 2011 #5
    Ok thanks.

    is this called plugging?

    Because if it is then it is not regenerative. When you plugging you draw big current from the supply to stop to ac motor.
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