A salient or project pole type alternator is the one in which projecting poles are mounted on the circular steel frame that is fixed on shaft of alternator.
The EMF generated in a conductor at any instant is mathematically given by:
e = Blv volts
Where in above equation:
- B = instantaneous value of flux density in Wb/m²
- l = length of conductor in metres
- v = speed of conductor in m/s
EMF generated is directly proportional to flux density. (Since I and v are constant)
In case of salient pole type alternator, sine wave of flux density is obtained by suitably shaping the pole shoe so that air gap gradually increases from center to pole tips.