Abstract
The increased reliability and ultimately reduced
life cycle cost of high and premium efficiency three phase motors
in a process control application is discussed. The reduced energy
consumption of these motors is evaluated in a public water
system case study under variable frequency conditions. The
importance of the consideration of a combined system, which
includes variable speed control, motor and load - as opposed to
only replacing with high efficiency motors for energy saving
purposes - is practically observed and reported on. The paper
reports on the marginal improvement in energy consumption at
reduced supply frequency for motor replacement only (not
surprising) but a very impressive 46% saving in energy
consumption by controlling pumped water at a reduced but
constant delivery rate.