Question

Expression for instantaneous value of induced emf

Answer 1

Here,

only the cosine component (which is perpendicular) imparts emf to the rotation coil.

So,

flux linkages of the coil will be

= number of turns in the coil × flux linking

φ = n × φmaxcoswt

now,

the emf will be

E = -d[φ]/dt

= -d/dt[n × φmaxcoswt]

thus,

E = n × φmaxw.sinwt

here maximum value of emf will be [for sinwt = 1]

Emax = n × φmaxw

thus,

we have

E = Emaxsinwt

or

E = Emaxsinθ

which is the instantaneous value of emf, continuously changing with time or angle.

now,

if θ = 360 degrees

sinθ = 0

thus,

we have

E = 0