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Which capacitor shall i use for 3 phase 5 HP pump? how?

  1. May 17, 2015 #1
    I'm using a 3 phase 5HP motor pump n want to use capacitor. Which capacitor should I use and how to connect it to all the three phases?
    Please do needful
  2. jcsd
  3. May 17, 2015 #2


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    Gold Member

    Do you mean a start-capacitor for an asynchronous motor?

    The phase coils are not symmetric, as the start coil is dimensioned for a smaller current. Call the three phases as for the coils R, S, T, where T is the starting coil. Connect R and S directly to the net, and T connected to e.g. R through the capacitor. The motor will start in one direction. Connect T to S through the capacitor, and the motor will start in the opposite direction.

    When the motor has started, you may disconnect T. The motor will continue running in the starting direction, which is due to different impedance in the motor as to synchronous/counter synchronous direction.

    The size of the capacitor will emerge from the specifications of the motor.
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