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How to change the frequency of AC mains supply

Discussion in 'General Electronics Discussion' started by Emam, Jan 5, 2016.

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  1. Emam

    Emam

    58
    2
    Jul 7, 2014
    Dear all,
    I have a pump. this pump should be connected directly to the mains AC supply of our building to work.
    It means that the pump needs 220 V and 50 Hz frequency to work.

    Now I would like to change the flow rate of the pump.
    The flow rate can be changed by changing the supply freuqncy.

    Could you please tell me an easy way to change the AC frequency of the mains supply?
    Is it possible to have something like "frequency variator"?

    Bests regards
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
  3. Emam

    Emam

    58
    2
    Jul 7, 2014
    Thank you.
     
  4. Bluejets

    Bluejets

    4,056
    847
    Oct 5, 2014
    And possibly a 3 phase motor.
    Depends on how low you want the speed but go too low with a single phase motor and the start windings will re-energise and possibly burn out the motor.
    You may also use a valve to throttle the flow.
     
  5. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    Inefficient in terms of electrical energy use but possibly much easier and less expensive to build.
     
    Bluejets likes this.
  6. Minder

    Minder

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    Apr 24, 2015
    If you only need to lower the flow, you can throttle the intake, if it is a impeller pump the current will drop when throttled off.
    As mentioned, do not try a variable frequency on a 1ph cap start induction motor, especially a pump, they drop out of run under load at low rpm.
    M.
     
  7. Tha fios agaibh

    Tha fios agaibh

    2,096
    703
    Aug 11, 2014
    I would use a bypass valve that dumps excess pressure back to the inlet or tank.
    This is better than dead heading the pump.
     
    Gryd3 likes this.
  8. Minder

    Minder

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    Apr 24, 2015
    This is most likely a impeller driven pump, if so any restriction will reduce current in the motor, I doubt we are talking of a gear pump or similar?
    M.
     
  9. dorke

    dorke

    2,342
    665
    Jun 20, 2015
    Please don't let us guess.
    What is the brand and model or datasheet or even a photo of the pump.
    In short: Help us help you:)
     
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