Page 618 - Basic Electrical Engineering

Fig. 7.10 shows a single conductor rotated by a prime mover in a magnetic field.

Let us assume the following:
No. of poles = P.

Flux per pole = ϕ Wb.
Speed of the driving prime mover = N rpm.

Actual number of armature conductors = Z.
Number of parallel paths of the armature winding = A.

Induced EMF in the conductors will be due to relative velocity between the conductor and the flux
produced by the field poles.

When the conductor in Fig. 7.10 makes 1 revolution, the flux cut by the conductor = Pϕ Wbs.

(The students will appreciate that if there were two poles and flux per pole
was ϕ Wbs.

The conductor is rotating at a speed of N rpm or (revolutions per second)

Time taken by the conductor to make 1 revolution = seconds.

Figure 7.10 Development of equation for EMF induced

7.3.1 Induced EMF Is Equated to Flux Cut Per Second

Therefore, induced EMF in 1 conductor