From the Spring 2007 issue of Energy Matters
Electric motors consume more electricity than any other end-use technology in industrial and commercial applications. But today's energy-efficient and premium-efficiency motors (PDF 211 KB) can substantially reduce your energy use and costs. So, you don't have to be resigned to sky-high utility bills just because your plant relies heavily on motor-driven systems. Download Adobe Reader.
The answer to these savings (and lower environmental emissions) lies in the motor's efficiency — its shaft or mechanical output power divided by its electrical input power. Motor experts have shown that an improvement in efficiency (PDF 261 KB) of a single percentage-point is worth significant dollar savings, even for motors as small as 10 horsepower (hp). Download Adobe Reader.
For example, purchasing and using one premium-efficiency, 50-horsepower, totally enclosed, fan-cooled (TEFC) motor (1,800 rpm) instead of a motor just meeting the energy-efficiency requirements specified in the Energy Policy Act of 1992 can reduce your plant's electric bill by more than $190 per year. This savings assumes that the motor operates at 75 percent load for about 8,000 hours per year at a utility cost of 5 cents per kilowatt-hour. A 10-hp premium-efficiency TEFC motor used under the same conditions can save $60 per year per unit. So, when plants need to replace numerous smaller motors, the savings can add up quickly. (For more information on the energy-saving impacts of premium-efficiency motors, see the related article in this issue.)
Here are some helpful tips developed by experts on motor efficiency for the DOE Industrial Technologies Program. Each title below is followed by a link to a concise, two-page publication designed to help engineers, technicians, equipment operators, and others increase the efficiency of their motor systems. Download Adobe Reader.
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Eliminate Voltage Unbalance (PDF 199 KB)
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Replace V-Belts with Cogged or Synchronous Belt Drives (PDF 647 KB)
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Avoid Nuisance Tripping with Premium Efficiency Motors (PDF 241 KB)
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Estimating Motor Efficiency in the Field (PDF 261 KB)
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Extend the Operating Life of Your Motor (PDF 190 KB)
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The Importance of Motor Shaft Alignment (PDF 312 KB)
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When to Purchase NEMA Premium-Efficiency Motors (PDF 211 KB)
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