The next improvement in maintenance technology was the advent of predictive maintenance, which is based on the determination of a machine’s condition while in operation. The technique is dependent on the fact that most machine components will give some type of warning before they fail. To sense the symptoms by which the machine is warning us requires several types of non-destructive testing, such as oil analysis, wear particle analysis, vibration analysis, and temperature measurements. Use of these techniques to determine the machine condition results in a much more efficient use of maintenance effort compared to any earlier types of maintenance.
Predictive maintenance allows plant management to control the machinery and maintenance programs rather than vice versa. In a plant using predictive maintenance, the overall machinery condition at any time is known, and much more accurate planning is possible.
Predictive maintenance utilizes many different disciplines, by far the most important of which is periodic vibration analysis. It has been shown many times over that of all the non-destructive testing that can be done on a machine, the vibration signature provides the most information about its inner workings.
Certain machines, which would affect plant operations adversely if they were to fail, can be subjected to continuous vibration monitoring, in which an alarm is sounded if the vibration level exceeds a predetermined value. In this way, rapidly progressing faults are prevented from causing catastrophic failures. Most modern turbine-driven equipment is monitored in this way.
Oil analysis and wear particle analysis are important parts of modern predictive programs, especially in critical or very expensive equipment. Thermography is the measurement of surface temperature by infrared detection, and is very useful in detecting problems in electrical switchgear and other areas where access is difficult.
Motor current signature analysis is another technique that is very useful in detecting cracked or broken rotor bars while the motor is in operation, and electrical surge testing of motor stators is used for detecting incipient electrical insulation failure.
SymphonyAI Industrial provides products, software & services for Predictive Maintenance including vibration analysis instruments, wireless vibration monitoring, asset performance management and process health and optimization.