Why is transformer efficiency higher than motors or generators?

naveee

naveee

@naveee-QD5zHH • Oct 27, 2024
Can someone tell me why is transformer efficiency is higher than motor and generator? Transformer efficiency is generally greater than 95%, while that of the motors its ~70%. Both are electrical machines, so why's such a difference between the efficiencies?

PS: Edited By Admin. Added more description to make the question clearer to understand.
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  • Abhishek Rawal

    Abhishek Rawal

    @abhishek-fg9tRh • Dec 7, 2012

    Transformers has copper & core loss.
    Motor or Generator has Mechanical loss (Friction loss & Windage), Core loss (Stator core & Rotor core) & Copper loss (Stator Cu & Rotor Cu).
    Hence Generator/Motor has less efficiency than transformers.

    I will suggest you Electrical Machines by B.L.Theraja .It's like Bible for me for EM.However I don't have any problem in answering the question 😀
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  • pinank

    pinank

    @pinank-6TUo5O • Dec 9, 2012

    generally the copper loss are negligible in AC machines as the reluctance is much more than the resistance.. so taking this into consideration the transformers have core loss bt motors and generators have frictional in mechanical losses...so the efficiency of transformers is higher!
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  • zaveri

    zaveri

    @zaveri-5TD6Sk • Dec 9, 2012

    Maybe i think #-Link-Snipped-# and #-Link-Snipped-# have a point

    motors and generators have moving parts, and frictional losses as well as transmission losses at the bearings take place, which however do not take place in a transformer.
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  • Jeffrey Arulraj

    Jeffrey Arulraj

    @jeffrey-xA7lUP • Dec 9, 2012

    All the same comes Harmonic generation in rotating parts loss in harmonics are also prevalent in these rotors reducing efficiency rapidly
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  • Henri

    Henri

    @henri-7eYVw8 • Dec 10, 2012

    generally,most of the energy losses in transformers are minimized effectively and again they are few,,,for instance eddy currents being minimized by use of soft iron core.....but motors and generators have so many energy losses especially due to moving parts,,remember transformers are kind of static with only flow of energy taking place whereas motors are dynamic and with lots of moving parts...considering friction and other factors makes them less efficient
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  • revathi.geeda

    revathi.geeda

    @revathigeeda-FwgB7v • Oct 15, 2015

    efficiency of transformer is higher than that of motors why??
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  • sunil kumar singh

    sunil kumar singh

    @sunil-kumar-singh-Iauz9n • Nov 16, 2015

    As the transformer is a static device so the windage and cupper losses are not present ,but motor or generator are not static device so windage and cuuper losses are present ,therefore the efficiency of motor or generator is less than the transformer,in transformer only cupper and core losses are present and its effinciecy is more than 95% and the effinciecy of motor or generator is approx. 70%...
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  • MANISH KUMAR

    MANISH KUMAR

    @manish-hzWU8v • Dec 13, 2018

    The efficiancy of trasformer is high because there are no dynamic losss it is a static device

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