By the estimate of the U.S. Energy Department, there are more than 13.5 million electric motors in use in U.S. industrial process operations today. Manufacturing alone spends more than $33 billion to keep those motors running, which accounts for nearly 70% of all electricity used in industry.
Those staggering numbers go a long way toward explaining why innovations in motors and drives have been focused on maximizing power efficiency.
Over the last decade, energy costs have steadily escalated, while the federal government has instituted new regulations that mandate power efficiency. Currently, Congress and the Environmental Protection Agency are weighing new regulations that would tax companies on emissions.
"It's an issue that for everyone is top of mind," says Randy Breaux, vice president of marketing for Baldor, a manufacturer of motors. "But even before all that, you saw companies making the move [to more efficient motors] because they recognize the benefits of using a higher efficiency motor and reducing their electricity costs."
Baldor's Super-E high efficiency motors, shown here driving pumps at a wastewater application and powering a conveyor, offer increased efficiency and long-term energy cost savings.
EISA raises the minimum energy efficiency requirements of these motors and encompasses Subtype II motors not previously within the EPAct scope, such as close-coupled pump motors, vertical motors and motors from 201 hp to 500 hp, all of which must now be rated to at least NEMA Energy Efficient.
These changes are significant. OEMs will be required to upgrade from a standard efficient motor on machinery they produce to a premium efficient motor. The only motors available on the market after December will meet federal requirements, but cost between 15% and 30% more to purchase.
Those costs, however, can be a bit misleading when viewed over a long period of time. Consider that the lifecycle cost of a typical AC induction motor consists of only 2% for the purchase price and over 97% for the energy used over its life, according to Baldor's Breaux. The added efficiency on premium efficient motors will recover the added cost in six to 12 months, he said, and continue every year afterward over the 15-year to 20-year lifecycle of the motor.
Another significant trend has been efficiency gains achieved through the use of better electrical-grade steel. Motors have begun incorporating aluminum and greater use of copper and permanent magnets, says Brayton Knotts, general manager of the motors division at General Electric.
"The standard induction motors that you see in general industry are using materials that are different than you'd see in a servo motor," says Knotts. "They're using exotic magnets to produce higher torque in smaller packages."
Equally important has been the increased communication between motors and drives, making it possible to save data on each and every component on the system.
"When you connect these motors together, all that data is collected, not just the speed or the position," says Craig Nelson, product marketing manager for Sinamics-S servo and vector drives at Siemens.
"All that feedback is automatically fed into the drive, such as the temperature of the motor, its performance, even diagnostic warnings. They become a single component and make it very easy to use. Someone doesn't have to go in and manually set all those parameters."
The next generation of motors promises to be higher in efficiency, smaller in size, use less material and made from more exotic metals. Baldor has been working with the Energy Department for the last two years in designing a new motor that can vastly improve performance and efficiency for industrial applications.
"This project will create a smaller, lighter and more efficient motor than is currently available," says Baldor's Breaux. "We're a ways away from there, but I can tell you that we do have motors that are running in the lab, so the technology is feasible. I can't say much more about it. But what I can say is it's a very different technology and very exciting."