MAINTENANCE LOG
You may also consider vibration-measurement instruments to not only identify stages of bearing failure, but to also identify overall machine performance and problems. Sensors mounted to the bearing may include permanently mounted or portable magnetic-base accelerometers, displacement probes or velocity pickups. Sensor selection is dependent upon the bearing speed, sensitivity requirements and the application. Although vibration feedback is highly desirable, proper training is important due to the complexity in data collection and interpretation. Lubrication. . . Simple tests can also be conducted on purged grease to detect hard-particle contaminants. After re-lubrication, the technician should rub some freshly purged grease between his/her fingertips. Gritty grease may indicate a need for more frequent lubrication—or wear from a failing bearing. LMT Galen Burdeshaw is Baldor’s Customer Order Engineering Manager for DODGE Bearings and PT Components. For more info, enter 03 at www.LMTfreeinfo.com
Many bearing manufacturers offer various permanently mounted sensors pre-installed on bearings that provide online, real-time monitoring of temperature and speed.
Portable thermal imaging tools offer a quick and efficient means of monitoring bearing performance. These devices use infrared (IR) thermography to visually identify variations in temperature—the most common being the infrared thermometer. Although portable thermal imaging tools typically can’t measure temperatures over a broad area, they’re inexpensive and easy to use. Vibration. . . Vibration analysis is the most information-rich method available for bearing analysis—and touch is a good way to distinguish between smooth and rough operation. As safety permits, feel the bearing housing during operation. Rough operation, jostling or grinding may indicate a bearing problem. Utilizing a portable temperature-measuring tool, like a thermal imaging gun, will help you accurately monitor bearing temperature. As a bearing fails, its temperature will continually increase. Trending temperature over time will help identify a bearing in the early stages of failure.
18 | LUBRICATION MANAGEMENT & technology
SEPTEMBER/OCTOBER 2013