Back EMF & Rotor Flux: Synchronous Motor

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Back EMF in synchronous motors is influenced by the rotor's magnetic flux, as described by the equation Ea=k*phi*w, where Ea is the back EMF, phi is the magnetic flux, and w is the angular velocity. The interaction between the three-phase field windings and the wound rotor creates a rotating magnetic field that maintains synchronous rotation. The discussion highlights the importance of understanding the specific type of back EMF being referenced, as various contexts may apply. Additionally, the thread includes links to previous discussions and visual resources that illustrate these concepts. Understanding these dynamics is crucial for effectively analyzing synchronous motor performance.
Passionate Eng
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how is the back emf affected by the flux of the rotor?
I know the relation : Ea=k*phi*w
but i need a physical explanation
 
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Three phase field windings produce a rotary traveling magnetic field.
The wound rotor has a magnetic field.
The two fields lock to maintain synchronous rotation.

Which back EMF are you referring to ?
 
I made these drawings* some years ago for another thread that i can no longer find.

but you might find these two really old ones helpful
https://www.physicsforums.com/threads/synchronous-generator.538388/
https://www.physicsforums.com/threads/synchronous-generator-again.571174/
ugenetic1_zps528def0e.gif


ugenetic2_zpsb383c1b1.gif


ugenetic3_zps0b47bca3.gif


*They're hotlinked from Photobucket, an image hosting site where i placed them before PF had its "Upload" button, so the hotlink isn't inconveniencing anybody(see https://www.physicsforums.com/threads/hyperphysics-images.868337/ )

Here are two more old threads that might help
https://www.physicsforums.com/threads/armature-reaction-drop.826513/#post-5191404

see especially the animation linked in post 2 of this thread :
https://www.physicsforums.com/threa...et-alternator-under-load.754838/#post-4754007
 
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