In an alternator, the nature of armature reaction at zero p.f. leading loads is
Right Answer is:
The effect of the armature flux on the main flux affecting its value and the distribution is called armature reaction.
In an alternator, the nature of armature reaction at zero p.f. leading loads is Magnetizing.
Zero Leading Power Factor Load (Magnetizing) Under-excited
Consider a purely capacitive load connected to the alternator having zero leading power factor. This means that armature current Iaph driven by Eph leads Eph by 90° which is the power factor angle φ. Induced e.m.f. Eph lags φf by 90° while Iaph and φa, are always in the same direction.
The armature flux and the main field flux are in the same direction i.e. they are helping each other. This results in the addition of the main flux. Such an effect on each armature reaction due to which armature flux assists field flux is called the magnetizing effect of the armature reaction This effect adds the flux to the main flux, greater e.m.f. gets induced in the armature Hence there is an increase in the terminal voltage for leading power factor loads.