Why we use Three-phase
not four phases or other
Why
we use Three-phase not four phase or other
Three
phase power has
several
advantages over
single
phase power,
including
smaller
Transformer
size and weight,
and
simplified motor construction. Four phase
power,
which is actually two
phase
power with the
phases
in quadrature (90°
apart),
doesn't really offer
any
advantage over three phase power but requires an
extra
conductor. Some
experimental
work has been
done
with 6 and 12 phase
power,
but these have never
been
put into common usage. When you consider
the
cost of long transmission
lines
from the power source,
three
phase power is the
best
alternative.
