01 October 2002
Shake, rattle, and roll on
Bismarck, N.D. - Managers of power plants and other industries with large rotating turbines are constantly concerned about catastrophic failure caused by machine vibration. To prevent it, many buy proprietary "protection systems" that cost in the range of $80,000 to $150,000 each.
Installing them may cost that much again, or more. For example, a 4-20 mA-based protection system that monitors 21 points on a turbine 800 yards away from the control room requires 11 miles of cable. Inside the control room, a centralized rack cabinet larger than a refrigerator houses operating components and expensive cooling equipment to prevent overheating.
Because traditional protection systems are designed to stop only catastrophic failure, plants must plan periodic shutdowns so maintenance personnel can check the equipment for developing faults that could ultimately lead to big problems.
Aiming to significantly improve plant uptime and cut users' "cost of ownership," Rockwell Automation developed a modular, distributed machine monitoring and protection system that's quite different.
Called the Entek XM series, it consists of a network of small, DIN-rail-mounted intelligent modules that continuously monitor critical plant floor machinery and equipment. The modules identify and report developing faults based on actual asset condition rather than manufacturers' recommended preventive maintenance schedules, said Rick Schiltz, P.E., vice president of capabilities and engineering for Rockwell's Integrated Condition Monitoring (ICM) Solutions business group.
Using open Ethernet, ControlNet, Profibus, or Modbus gateways, XM can integrate with other control systems. Instead of 11 miles of cable for that turbine located 800 yards away from the control room, XM would need only half a mile of cable.
Routine condition monitoring could all occur wirelessly, and each XM module is "hot swappable," meaning you can quickly replace it without shutting down power. Inside the control room, that refrigerator-sized equipment rack would look more like a breadbox and require no cooling.
"On average, predictive maintenance activities can reduce maintenance repair and operations costs by 10% to 30% and increase return on net assets," Schiltz said.
When Bismarck-based Dakota Gasification heard about the XM, it stopped plans to buy a traditional protection system for one of its turbines, signed nondisclosure agreements, and became an XM beta site.
"The XM series' ability to capture fault data across a network is something we're keenly interested in applying, as it provides the information necessary to accurately identify the problem and its cause," said Angela Berger, Dakota Gasification plant reliability engineer.
- Jim Strothman
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