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Application Notes:
Thermal Imaging and Motor-Conditioning at a Papermill |
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Until three years ago, the only thermography performed at the specialty paper mill featured in this case study was done by a consulting firm that inspected the switchgear once a year. The inspectors usually found hotspots that needed to be eliminated, but after plant technicians performed a fix, it would have been cost prohibitive to call the consultants back to verify that each repair was successful. |
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Bill Gray, the plant's maintenance reliability specialist, trained in its use and became a Level I Thermographer. Gray began conducting thermal inspections of equipment as needed. Now, having used the thermal imager for two years, he's using the experience he's gained to develop a formal motor-condition monitoring reliability maintenance program.
Post-repair and other applicationsThe paper mill still contracts with outside thermographers to monitor the switchgear once a year, because of the time it takes to do a complete survey. The contractor surveys about 5,000 pieces of equipment over a week.
However, when Gray started taking thermal images of the repairs performed as a result of those outside thermographers' finds, he discovered that about 30 percent of the repairs were either unsuccessful or had made things worse.
Motor monitoringThe mill is still in the process of developing its own thermal inspection routes. So, they started out by using thermal images on an "exceptional occurrence" basis. In other words, if someone walks past a motor and notices it's hot, then Gray take a thermal image to find out where and why the motor is hot. If vibration data indicates a bad bearing or imbalance, he can confirm those findings with the camera by finding out if the motor is hot and where it's hot.
The mill has approximately 3,000 motors ranging from fractional horsepower units on pumps that supply coating and additives to 1,000-horsepower units powering large operations. If even that little pump motor fails, a whole batch of paper can be ruined or the machine shut down.
Moving toward a formal motor-monitoring programAs part of the formal motor monitoring, Gray will concentrate on shafts, couplings, gearboxes and other mechanical components. Once the inspection routes and schedules are finalized, he hopes to get the maximum life out of his expensive, high-horsepower motors.
He'll be combining data from visual inspections, infrared spot thermometer checks, vibration analysis, thermography and current-phase analysis into a new condition-based monitoring and asset management system.
By putting all the analysis data together into one picture, he'll be able to deal most effectively with...
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