Efficiency Overview

More than 300 million motors are used in industry, large buildings and in infrastructure globally, and approximately 30 million new electric motors are sold each year for industrial purposes alone.

Electric motor driven systems (EMDSs) in industry are estimated to be responsible for approximately 29% of overall global, and 69%of industrial electricity consumption.

Motors are grouped into three main categories as small, medium, and large. Of these, medium class motors (with an output between 0.75 and 375 kW) are responsible for 67.6% of electricity used in all motor systems. The share of small (0.001 to 0.75 kW) and large (375 to 100 000 kW) motors are 23.3% and 9.1% respectively. Although their numbers are low, large electric motors are significant energy consumers due to their high power demand.

General Industry Characteristic:

With a share of 64%, industry consumes the most power for electric motorized applications. The next most important sectors are the commercial sector (accounting for 20% of all motor‐electricity consumption) and the residential sector (accounting for 13%). The transport and agricultural sectors contribute only marginally to global motor‐electricity demand.

High-Efficiency Motors

Motor efficiency is determined by two main factors: the size of the motor and its efficiency quality. While for the smaller motors the size is the predominant factor affecting efficiency, for the larger motors efficiency classes becomes more important.

Standard AC squirrel‐cage induction motors are the most commonly used motor types industry and offer an effective way of continuously operating pumps, fans, compressors and conveyors, etc. at fixed speed. For the medium sized AC induction motors, efficiency standards are available and currently divide the motors into three categories, namely: standard efficiency -IE1, High efficiency – IE2, Premium efficiency – IE3. Introduction of a new Super Premium class (IE4), that will be 15% more efficiency than IE3 type motors are indicated to stimulate competition. Information about performances of motors in different efficiency classes can be derived from the following graph.

High efficiency motors reduce energy losses through improved design, better materials, tighter tolerances, and improved manufacturing techniques. With proper installation, energy-efficient motors can also run cooler and have higher service factors, longer bearing life, longer insulation life, and less vibration. These motors are about 85 – 96% efficient, depending on size. Premium efficiency motors are the most energy efficient motors widely available today.