if we apply any wave form other than sine wave to the transformer the output is spikes due differentiation and devices dont work for those spikes and damage all home appliances so we use sine wave only
the nature of sine wave is exponentionally
increasing&decreasing,we know that any system components
can have some cutin voltage regions ,in that region the
system accepts slow +ve&-ve increasing&decreasing
sigals,every system contains semicondutor devices,because
of non linearity property of semiconductor ,the sine wave
has the same property.so it can be used.
actually the design of alternator which give power to us in
only for sinewave or cosine wave, bt when v use to generate
cosine wave only 3/5 of angle can rotae smooth...... coz
wile 2nd phase start it neutralise second so no resultant
force will be there for generation of power............