Icebergs were much in evidence in South Carolina on Oct. 15—not off that southern state’s seacoast, but on the educational and promotional materials passed out by motion products vendor SEW-Eurodrive (www.seweurodrive.com) during the energy efficiency seminar it hosted at its U.S. plant in Lyman, S.C. Like an iceberg, most of the total cost of ownership (TCO) of a machine or system lies below the surface, that is, after the initial purchase. Training, spare parts, maintenance, insurance and various other factors boost the TCO, but none more so than energy.
“In terms of the total investment in a production system, electrical drives represent only a small percentage of the financial outlay,” noted Dr. Meinhard Schumacher, SEW’s point man on TCO and the seminar’s presenter. “Energy consumption, however, has a major impact on follow-up costs.” Make your electrical drives more efficient, said Schumacher, and you can significantly reduce your system’s TCO.
The German Electrical and Electronic Manufacturers’ Association (commonly known by its German acronym ZVEI) approached this issue from a slightly different perspective when it noted that two-thirds of industrial energy consumption is accounted for by electric motor-driven systems. ZVEI estimates that 15 percent of that amount could be eliminated through the use of more energy efficient electrical drive technology.
But don’t think you can simply install more efficient motors and automatically reap this degree of savings, cautioned Schumacher. Applications should be crafted to meet the needs of the specific applications, he insisted. Individual components must be chosen carefully and combined with the appropriate drive technology to match the specific application, he said, adding, “Only the intelligent combination of efficient components will lead to an energy efficient solution.”
Not surprisingly, SEW-Eurodrive believes it has the components and technology required—components such as its DR Series motors, which, designed for energy efficiency, are slated to replace the company’s AC motors in 2009, and the award winning Movigear. Deemed a mechatronic drive solution, this new offering features a compact design, high overload capacity, low noise emissions and, according to SEW, short installation time, along with Ethernet-based networking features.
The thrust of the seminar, though, was about process not product, about saving energy rather than patronizing a specific vendor, and complying with increasingly stringent European Union and U.S. regulations governing energy efficiency.
A big example
Among the examples given, the one that seemed to resonate most strongly was that of a BMW plant in Bavaria. Rather than rely on air conditioning, the plant used 24 ventilation systems installed on building roofs, with each system consisting of four large fans. The fans were powered by pole-changing asynchronous motors with speeds controlled via temperature difference. SEW replaced this system with more energy efficient motors whose speed is controlled by SEW Movidrive/Movitrac inverters. Now, the motors can be adjusted to the actual requirements via speed control. As a result, energy consumption per drive per year has been reduced from 83,500 kilowatt-hours (kWh) to 72,000 kWh.
Though this application was larger than most, Schumacher maintained it is by no means atypical, saying “there is always potential for saving energy.”
About the author
Greg Farnum, firstname.lastname@example.org, is an Automation World Contributing Editor.