CrazyEngineers
CrazyEngineers

  • Speed regulation in ceiling fan

    parin bumia

    Member

    Updated: Oct 27, 2024
    Views: 1.1K
    I want to ask how the speed regulation is done in case of ceiling fans. Also, as how the speed of the fan changes on changing its capacitor, that is, I have found that speed of fan increases on changing capacitor - but how, I've always wondered.
    0
    Replies
Howdy guest!
Dear guest, you must be logged-in to participate on CrazyEngineers. We would love to have you as a member of our community. Consider creating an account or login.
Replies

  • zaveri

    Member • Sep 30, 2012

    when capacitors are connected in parallel, then the net the capacitance increases and hence fan speed increases.

    but when they are connected in series, the reverse takes place.
    Are you sure? This action cannot be undone.
    Cancel

  • zaveri

    Member • Sep 30, 2012

    the older larger versions of regulators, which accompany a fan, work by changing the series resistance.

    the latest, versions , which are smaller in size, have a zener diode, and you know the rest.
    Are you sure? This action cannot be undone.
    Cancel

  • grsalvi

    Member • Oct 1, 2012

    zaveri has told correct about speed regulation.But about capacitors,they are meant for starting of 1 phase motor of fan.Nothing to do with speed.
    Are you sure? This action cannot be undone.
    Cancel

  • naveee

    Member • Oct 1, 2012

    zaveri
    when capacitors are connected in parallel, then the net the capacitance increases and hence fan speed increases.

    but when they are connected in series, the reverse takes place.
    plz still ther is confusion...how net capacitance increases the RPm ?? wt is the role of CAPAcitance in single phase induction motor ???
    Are you sure? This action cannot be undone.
    Cancel

  • Ramani Aswath

    Member • Oct 1, 2012

    zaveri
    the latest, versions , which are smaller in size, have a zener diode, and you know the rest.
    Not a Zener. They have a triac. Speed is controlled by varying the firing angle of the triac so that the applied voltage to the fan changes, therby changing the speed. The zener diode may be used for shifting the firing angle.
    Are you sure? This action cannot be undone.
    Cancel

  • Ramani Aswath

    Member • Oct 1, 2012

    naveee
    wt is the role of CAPAcitance in single phase induction motor ???
    You need a rotating magnetic field to achieve shaft rotation. The capacitor acts as a phse shifting device. Different capacitance values will achieve different levels of shift. It is possible that the original capacitor was suboptimally wired. The addition made by you might have achieved the best shift thereby causing a speed increase. If you add another capacitor you may over shift and get a lower speed even though the capacitance increased.
    Are you sure? This action cannot be undone.
    Cancel

  • naveee

    Member • Oct 1, 2012

    bioramani
    Not a Zener. They have a triac. Speed is controlled by varying the firing angle of the triac so that the applied voltage to the fan changes, therby changing the speed. The zener diode may be used for shifting the firing angle.
    firing angle ??? is juss a phase angle or someother thing ????
    Are you sure? This action cannot be undone.
    Cancel

  • naveee

    Member • Oct 1, 2012

    bioramani
    You need a rotating magnetic field to achieve shaft rotation. The capacitor acts as a phse shifting device. Different capacitance values will achieve different levels of shift. It is possible that the original capacitor was suboptimally wired. The addition made by you might have achieved the best shift thereby causing a speed increase. If you add another capacitor you may over shift and get a lower speed even though the capacitance increased.
    so due to negative phase shift in capacitor ..if capacitor increased ..rotating speed is decreased????
    Are you sure? This action cannot be undone.
    Cancel

  • grsalvi

    Member • Oct 1, 2012

    naveee
    firing angle ??? is juss a phase angle or someother thing ????
    "The value of phase angle of sinusoidal AC wave at which TRIAC is turned on (i.e. they allow flow of power to fan motor) is called firing angle.
    More is firing angle ,the TRIAC is 'turned on' late ,hence less power reaches the fan and its speed decreases.
    However TRIAC speed control is efficient compared to resistor regulators as there is no heat dissipation involved.
    Are you sure? This action cannot be undone.
    Cancel

  • grsalvi

    Member • Oct 1, 2012

    Single phase AC motor has two windings : main winding and auxiliary winding.
    Due to single phase supply the winding is able to produce a stationary sinusoidal field(for Rotating you need more than one phase like in 3 phase induction motors which do not need capacitors).
    So to run a single phase motor, Capacitor is added to auxiliary winding.The current in main and auxiliary winding come from same source but due to capacitance in auxiliary winding its current is leading.
    Hence the motor windings has more than one phases.
    This causes stationary field to rotate and turn the shaft .
    Are you sure? This action cannot be undone.
    Cancel

  • naveee

    Member • Oct 1, 2012

    grsalvi
    "The value of phase angle of sinusoidal AC wave at which TRIAC is turned on (i.e. they allow flow of power to fan motor) is called firing angle.
    More is firing angle ,the TRIAC is 'turned on' late ,hence less power reaches the fan and its speed decreases.
    However TRIAC speed control is efficient compared to resistor regulators as there is no heat dissipation involved.
    wow
    Are you sure? This action cannot be undone.
    Cancel

  • zaveri

    Member • Oct 3, 2012

    bioramani
    Not a Zener. They have a triac. Speed is controlled by varying the firing angle of the triac so that the applied voltage to the fan changes, therby changing the speed. The zener diode may be used for shifting the firing angle.
    yeah you are right. sorry i spoke too soon
    Are you sure? This action cannot be undone.
    Cancel

  • arunchary

    Member • Oct 4, 2012

    TRIAC is replacement of inductive (relay) switching to soft switching , and also it as good voltage controlling with respective to currents ,normally we have already developed homeautomation product we used TRIAC to switching and also speed controlling of fan,and it is efficiently working in realtime....
    Are you sure? This action cannot be undone.
    Cancel

  • parin bumia

    Member • Oct 17, 2012

    thanks..for ur answers...grsalvi...,bioramani sir and zaveri...now i m much clear abt the "speed regulation"..thanks a lot...
    Are you sure? This action cannot be undone.
    Cancel
Home Channels Search Login Register