Book excerpt: Revised and updated throughout, the second edition of Energy-Efficient Electric Motors provides guidelines for picking and using electric motors on an energy conservation and life-cycle cost basis - emphasizing both single- and three-phase motors in the 1- to 200-hp range that offer maximum opportunities for energy savings.;Maintaining the features of the first edition, this concise resource: explains current improvements in electric motor capabilities and recently adopted NEMA energy-efficient motor standards; contains a new section about the power factor with nonlinear loads; covers the performance of polyphase induction motors supplied by adjustable frequency power supplies for several types of loads, presents information on numerous kinds of power semiconductors used in variable-frequency power supply systems; provides expanded coverage comparing various types of adjustable speed drives when applied to constant torque and variable torque loads; and contains a new summary checklist criteria for selecting induction motors for adjustable frequency drive systems.;Generously illustrated with nearly 200 figures and tables, the second edition of Energy-Efficient Electric Motors is timely reading for electrical, electronics, mechanical, consulting, specifying, and plant engineers; plant and purchasing managers; original equipment, heating, ventilating, and air-conditioning manufacturers; and continuing-education courses in these disciplines.