Calculate the electromotive force E

[bassi ali]

hi,
How can I demonstrate the relationship of the electromotive force of a motor AC
thank you

 

[cnh1995]

hi,
How can I demonstrate the relationship of the electromotive force of a motor AC
thank you

Motional emf will be induced in the rotor. Use E=BLVsinθ*N (where v=rw and N=number of turns of rotor).

 

[cnh1995]

hi,
How can I demonstrate the relationship of the electromotive force of a motor AC
thank you

For detailed demo, you can first prove the motional emf equation using Lorentz's force(F=BILsinθ) applied on electrons of a conductor and then apply the emf equation to this alternator.

 

[bassi ali]

which force you talk about ?
the rectangle is fixed and the flow varies,
I think to use the flow of magnetic induction,
I think to use Faraday's relationship e = - dΦ / dt (the derivative currency flows on derivative temp).
in using Φ=∫∫ B.dS

 

[cnh1995]

the rectangle is fixed and the flow varies,

Then you should use Faraday's laws.

I think to use Faraday's relationship e = - dΦ / dt (the derivative currency flows on derivative temp).
in using Φ=∫∫ B.dS

Right.

 

[bassi ali]

but i find this expression : E = N L r w B cos(wt)
====> must find sin (wt) instead of cos (wt)

 

[cnh1995]

but i find this expression : E = N L r w B cos(wt)
====> must find sin (wt) instead of cos (wt)

Then you should assume the varying flux as a cosine wave.
sin(wt)=cos(π/2-wt).

 

[bassi ali]

i have cos(wt) not sin(wt) !

 

[cnh1995]

i have cos(wt) not sin(wt) !

Your varying flux function should be predefined, either sin or cos. If it is sin, emf will be in cos(wt).