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    speed control of single phase induction motor

    Hi everybody !!

    I want to run one single phase induction motor rated for 230V ac , with an electronic fan regulator as speed controller for the motor.

    I have done it but not gain the desired result. The induction motor runs at full speed or not running at all.

    Speed variation does not get performed. I think electronic fan regulator ( voltage controller) should work with that single phase motor.

    What would be the reason for it ?

    Regards!!!

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    single phase induction motor speed control

    is the regulator working by itself ?


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    single phase speed control

    There is big difference between running fan and running regular single phase async. motor.

    Asynchronous motor is very sensitive to variations in voltage and can only be regulated by means of changing frequency. Fan acts as feedback device, having low torque required at low speed and high torque at higher speed. By changing voltage torque is changed so fan balances at speed that reaches that supplied torque. If you took fan blades of the motor, it would behave in same way as you described: either full speed or stopped.

    If you build controller that monitors speed and corrects voltage to get to that speed, you could be able to have speed control just by changing voltage. This is no longer simple phase regulator with triac that you tried to use.



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    single phase motor speed control

    Yup dear , the regulator i have alrdy checked. It is working piece.....



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    single phase speed controller

    Fyne.
    sinisa made me curious,
    hope that could be true.


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    speed control of single phase induction motor

    If you are asking wether or not you can control the speed of a single phase motor, many other questions arise, To keep it simple...shaded pole, psc (your common furnace motors) and ceiling fans, as well as your universal (your common electric drill and portable hand saws) the kind that use brushes...yes they can be speed controlled, usually not very smooth.

    If it is a split phase or a capacitor start,(like your compressor motors or your machine motors) that need a constant torque application, and usually start under a heavy load, no way no how will these be controlled.

    Only in a three phase world will these heavier loads be speed controlled and never cheapily

    The smaller shaded pole and psc motors can be controlled with something as simple as a dimmer switch (provided your amp draw is not exceeded) or a dehummer switch,(specially made dimmers for fans).

    Sparky



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    Re: Single phase induction motor speed control



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    Re: Single phase induction motor speed control

    Hi,
    There are a few problems. You may not notice this as the motor you used as load is not that high a load.
    When you use phase angle control, you ARE controlling the SPEED, but you're also lower the torque. By phase angle control, you control voltage, and in turn torque is not constant and may/will cause a problem with large loads on the motor. The proper way to do it is constant V/f technique, where you change the frequency as well as the voltage. This can not be done with triac and is usually done with SPWM after rectifying the AC mains to DC.

    Take a look at these very carefully:
    http://ww1.microchip.com/downloads/e...tes/00843a.pdf
    http://ww1.microchip.com/downloads/e...tes/00887a.pdf
    http://ww1.microchip.com/downloads/e...tes/00967A.pdf
    http://techtrain.microchip.com/webse...18Fxx31_BW.pdf
    http://www.atmel.com/dyn/resources/p...ts/doc7545.pdf

    Hope this helps.
    Tahmid.


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    Re: Single phase induction motor speed control

    Quote Originally Posted by Tahmid View Post
    Hi,
    There are a few problems. You may not notice this as the motor you used as load is not that high a load.
    When you use phase angle control, you ARE controlling the SPEED, but you're also lower the torque. By phase angle control, you control voltage, and in turn torque is not constant and may/will cause a problem with large loads on the motor. The proper way to do it is constant V/f technique, where you change the frequency as well as the voltage. This can not be done with triac and is usually done with SPWM after rectifying the AC mains to DC.

    Take a look at these very carefully:
    http://ww1.microchip.com/downloads/e...tes/00843a.pdf
    http://ww1.microchip.com/downloads/e...tes/00887a.pdf
    http://ww1.microchip.com/downloads/e...tes/00967A.pdf
    http://techtrain.microchip.com/webse...18Fxx31_BW.pdf
    http://www.atmel.com/dyn/resources/p...ts/doc7545.pdf

    Hope this helps.
    Tahmid.
    MR TAHMID, u r very much right VF is the proper way to control the speed of an Induction motor & i know that very well, the biggest disadvantage of using Phase Angle Firing Control is reduction in torque, but man all small cheap machines uses "Phase Angle Firing Control" Technique . . . MR TAHMID BUILT ONE VARIABLE FREQUENCY AC MOTOR DRIVE & SHOW ME i wanna see . . .

    YouTube - Brushless AC Servo Motor Driver PI controller via PIC18F1320



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    Re: Single phase induction motor speed control

    we have a same project...can you give me a working circuit diagram of single phase induction speed control...if it is ok to you sir?....tnx



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