Another, more important characteristic of a balanced three-phase power
system may be illustrated by simplifying the circuits of Figures 7.46 and 7.48
by replacing the balanced load impedances with three equal resistances, R. With
this simplified configuration, one can show that the total power delivered to the
balanced load by the three-phase generator is constant. This is an extremely
important result, for a very practical reason: delivering power in a smooth fashion
(as opposed to the pulsating nature of single-phase power) reduces the wear and
stress on the generating equipment. Although we have not yet discussed the
nature of the machines used to generate power, a useful analogy here is that of a
single-cylinder engine versus a perfectly balanced V-8 engine. To show that the
total power delivered by the three sources to a balanced resistive load is constant,
consider the instantaneous power delivered by each source: