facility.”

Leon Kythas, Schneider product manager for packaged drives, adds a cautionary engineering note to those about to go out and just slap on a bunch of drives to existing motors. “Installing drives in older facilities where motors may have long power leads, or where the motors are designed only for full speed operation, can lead to potential problems such as nuisance tripping or premature motor failure,” he warns. “Engineers need to balance the motor/drive combination and check out the duty cycles, among other factors.”

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Dave Ballard, corporate manager of engineering and marketing at gearmotors and drives vendor SEW-Eurodrive, in Lyman, S.C., acknowledges the potential energy savings with drives, but he also encourages users to look at the entire system. “When the application includes a lot of cycling, starting/stopping or indexing, the energy savings can evaporate due to initial starting current. So look at the entire drive train. Is the entire system stable? Look at the gear boxes. Sometimes you can achieve 25 points of savings with just a newer gear box.”

Motors are a major energy user, so it makes sense to very thoroughly analyze all of them. But if the entire facility is ignored, then another chance for big cuts in the energy bill has been lost. Barry Contral, business unit manager for the Access Product Group at automation vendor Siemens Energy & Automation Inc., in Norcross, Ga., says, “Industrials have beat to death other costs, but the power bill is a big unknown. There are costs from the utility, such as a bad power factor charge or peak demand charges, that can be big. Unless you monitor it, you may never know that you should take action to solve those problems—or that perhaps the utility is overcharging you due to faulty measurements on their part,” Contral advises. “With a good power monitoring solution, managers can analyze parts of a plant and determine which processes or parts of the facility are the biggest users. Then they know where to look for the initial big savings.”

One last component that can be analyzed for energy savings is hidden in electrical enclosures all over the plant—constant voltage transformers (CVTs). One company that makes a capacitor-based filtering product, SoftSwitching Technologies, in Madison, Wis., has surveyed many companies, and its figures show that the typical CVT is about 50 percent loaded most of the time. Using industry numbers for transformer efficiency at that load, the company predicts almost $2 million per year savings using its product for a “typical” plant that has 2,000 CVTs rated at 6 kVA.  

For more information, search keywords “motors” and “energy efficiency” at www.automationworld.com

To see the accompanying sidebar to this story - “Cross-belt Energy Savings” - please visit www.automationworld.com/view-3009