New horses in the motor efficiency derby

Electrical Apparatus, Sep 2007 by Nailen, Richard L

As some distinctions among global motor standards disappear, others emerge

FROM SEATTLE TO SYDNEY, COPENHAGEN TO Cape Town, finding the same fast food and soft drinks, the same video entertainment, and the same cell phones-that's what "globali/ation" muy mean to travelers. But while many international distinctions have become blurred, new ones continue to appear. One example: the growing variety of standards and regulations around the world dealing with the efficiency of industrial electric motors.

In North America, although such recent developments as the 1992 Energy Policy Act have drawn widespread attention to the economics of motor efficiency, the issue is hardly new in the large-motor marketplace. For decades, users of those machines have placed a high dollar value on motor efficiency and have required that it be guaranteed.

Here's an example of how such a guarantee works. Based on past experience, or. in some instances, to just "push the envelope." a specifier calls for a certain high efficiency level as a baseline or point of reference. Bidders on the job are then ranked according to the efficiencies they are willing to guarantee. The buyer assigns a dollar value to each kilowatt of motor loss. The lower the efficiency (and therefore the higher the losses) in any quotation, the lower the acceptable motor price. On the other hand, guaranteeing a higher efficiency allows the bidder to set a higher price.

Figure 1 is typical. It's based on a 2,000 hp motor with losses valued at $4.000 per kilowatt; a "baseline" efficiency of 0.96 is assumed. The graph shows how rapidly the acceptable price drops as losses increase-a situation leading to quotations such as "95.65% efficiency." As experienced engineers have conceded publicly, that last "5" and even the next-to-last "6" cannot be considered certain.

With ever-increasing emphasis on saving energy, and more meaningful evaluation of what that energy savings can cost, extension of that economic concern into smaller motor ratings is inevitable.

Widening efficiency standards

For more than half a century, motor manufacturers in the U.S. published typical or design efficiencies, at least for the more highly standardized "NEMA frame" a-c ratings. But no NEMA or other industry standards have applied. The only pertinent test standard involved was IEEE 112.

By the 1980's, however, other agencies such as the Consortium for Energy Efficiency began agitating for efficiency standards in the motor industry, offering higher levels than the existing "industry average." Reluctantly, NEMA went along, even with the eventual adoption of the Energy Policy Act in 1992, recognizing that a single federal requirement was preferable to a hodgepodge of individual state regulations.

Progress overseas was slower. But we are now seeing an ever-expanding variety of worldwide motor efficiency goals and test standards. Some of the organizations involved began their work 30 or more years ago. Others have appeared only recently. Some evolved out of two or more other entities. We can list only the major ones here, in no particular chronological order:

First is the European Union, or EU. Its 73-page Directive 2005/32/EC established a regional "framework for the setting of ECOdesign requirements for energy-using products," including industrial motors (described as "ECO-motors," the "ECO" denoting "European Council").

A second agency now concerned with motor efficiency is the International Energy Agency, or IEA. In May 2006, this group hosted the Industrial Electric Motor Systems Efficiency Workshop in Paris. Participants invited the G8 countries to become involved in preparation of a detailed, worldwide study of commonly used motor systems and applications, leading to "a comprehensive global market transformation strategy to increase motor system efficiency." Also advocated was "work through the IEC to harmonize international test procedures . . . for electric motors," to arrive at "a single commonly used international test standard."

What is "G8"? That relatively informal group consists of government officials in the "Group of 8" industrialized nations (France, Germany, Japan, Russia, Canada, Italy, the U.S., the U.K.). G8 holds an annual summit meeting to discuss a wide range of issues, including energy and the environment.

Another group of importance is Standards for Energy Efficiency of Electric Motor Systems, or SEEEM. Its 15 members include national energy agencies (Austria, Switzerland, Canada, New Zealand); environmental groups in several countries; standards agencies (China); and Eurelectric (Union of the European Electricity Industry). Its goal: "to promote rapid market diffusion of high-efficiency motor component technologies and systems worldwide," by seeking (through several Working Groups) "greater alignment of international testing procedures, performance requirements and labeling schemes. . . ."

Organized in 1991 to represent the interests of motor manufacturers is CEMEP, the European Committee of Manufacturers of Electrical Machines and Power Electronics. It functions somewhat like NEMA though with a much narrower scope, as shown in Figure 2. (For more detail on CEMEP activities, see "Choosing motor efficiency: Europe versus U.S.," in EA February 2004.)