Why is transformer efficiency higher than motors or generators?

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.

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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!

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.

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

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

efficiency of transformer is higher than that of motors why??

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%...

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