Motor Efficiency Impacts Bottom Line

Motors eat up 63 percent of electricity consumed in today’s factories and plants. And while industrial motor users can’t control the price of electricity, they can take steps to reduce their electrical power consumption  through the use of higher efficiency motors and variable frequency drives. What’s more, the savings can be substantial over the 20-year life of a motor.

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That’s the message that industrial motor manufacturer Baldor Electric Co. (www.baldor.com), Fort Smith, Ark., and Motion Industries Inc. (www.motionindustries.com), a Birmingham, Ala.-based distributor, were looking to get across during a recent Chicago seminar for motor end-users. About 80 customers turned out for the Nov. 2 event, titled “Proper Selection of Electric Motors for Increased Reliability and Energy Savings,” according to John Malinowski, Baldor’s product manager for AC & DC motors.

By the numbers

Malinowski detailed the numbers during a presentation before the group, comparing life cycle cost between a conventional motor and one designated NEMA Premium—a motor efficiency specification set out by the National Electrical Manufacturers Association.

Only about 2 percent of the life cycle cost of a motor is in its purchase price, Malinowski said. So even though a NEMA Premium motor will cost more up front than a non-premium motor, that cost is quickly offset by its lower electrical consumption.

According to U.S. Department of Energy surveys, the average 200 horsepower motor in use today—a typical size for a compressor application, said Malinowski—is about 93.5 percent efficient. That compares to 96.2 percent for a NEMA Premium motor. For a motor that runs continuously at a cost of 7.5 cents per kilowatt hour, a NEMA Premium motor will cost about $3,000 less per year to operate—at $101,869 vs. $104,839 for the average non-premium motor, Malinowski told the audience. That’s an annual savings of around $3,000, which translates to $60,000 over 20 years of
operation, he said.

Not all motors run continuously, of course, and the savings would be less for motors smaller than 200 horsepower. But given the tens or hundreds of motors of all sizes running in many plants, its not hard to see how the combined savings of using all NEMA Premium motors could add up to big numbers.

The key to successfully implementing a motor purchasing policy based on life cycle cost—instead of lowest initial cost—is to get management buy-in, Malinowski said. “This is what we’re trying to get you to do, to go to management in your companies. You really need the commitment from the top to make the better investment.”

He recommended setting motor energy savings goals and developing an action plan for achieving those goals.

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