Over the past few decades, energy efficiency in motors has become an ever-increasing concern for OEMs and
manufacturers alike. With multiple
energy bills mandating higher efficiency across ever-broader spectrums of motors, including the most recent Small Motor Rule by the Department of Energy, efficiency has become an essential consideration when choosing a new motor.
According to the Department
of Energy (DOE), more than
half of all electrical energy
consumed in the U.S. is used
by electric motors. To address
this, several years ago, the DOE conducted
a technical study as to what
could be done to raise the efficiency
levels of “small” motors. After years
of study and litigation, the Small Motor Rule (SMR) was passed that covers two-digit NEMA frame single- and three-phase ¼ through 3 horsepower
motors in open enclosures.
The use of motor structures which can concentrate magnetic flux allows ferrite PM motors to achieve performance and power densities that approach those of PM motors using rare earth magnets, but without the cost penalties and supply source concerns of rare earth magnets.