Predictive maintenance (PdM) is applied in order to find out the condition of in-service equipment with the aim of predicting the actual time when the equipment is due for maintenance. This approach helps to guide against the waste of money and time arising from performance of maintenance work done at the wrong time.
There are a number of benefits that can be drawn from predictive maintenance measures. In the first instance, it will help you to schedule or plan for corrective maintenance at the proper time. You can plan and budget for preventive and corrective maintenance if you know which of your equipment requires maintenance and when it is proper to carry out the maintenance work. It is also a veritable means through which one can avoid unexpected equipment failures. It will equally help to ensure increased plant safety, increased equipment performance, increased equipment durability, reduced accidents, fewer environmental impact and others.
There are various nondestructive testing technologies that are used in predictive maintenance in order to evaluate the equipment conditions. These aspects of predictive maintenance include vibration analysis, laser shaft alignment, air leak surveys, on-site dynamic balancing, corona detection, infrared, sound level measurements and others.
Vibration analysis or monitoring can be used on any type of rotating equipment. Though it is the most costly aspect of predictive maintenance program to plan and run but it is the most productive component that can be utilized on high-speed rotating equipment. This explains why it is the most widely used predictive maintenance technique. Vibration analysis can be classified into three categories namely, detection, diagnosis and prognosis. In detection, a broad source is utilized in measuring the level of vibration. The diagnosis of the fault detected is made. A professional will give a prognosis on the remaining life or possible failure of the equipment.
Laser shaft alignment is another aspect of predictive maintenance. In laser shaft alignment, several shafts are aligned with each other within a tolerated margin. This aspect of predictive maintenance can help in keeping a motor and machine within the tolerance margin. This helps to expand the life of the machine and increase its efficiency.
In a compressed air system, the single largest energy waste is air leakage. Air leak survey is an aspect of predictive maintenance through which air leakage can be detected. Ultrasonic detectors are utilized in air leak surveys in order to detect leaks. Some powerful detectors can detect leaks from more than 50 feet away even in a noisy plant environment.
On-site dynamic balancing can be utilized as a diagnostic tool in predictive maintenance. On-site dynamic balancing reduces the level of vibration caused by wear. It is also effective in reducing new components tolerances, dirt build up and power consumption. It also increases the life of the bearing and optimizes the machine operation. Dynamic balancing can be used in grinders, fans, mills, hay grinders, machine tooling, mixers, grain dryers and others.
Acoustical analysis is another aspect of predictive maintenance. It can be done on an ultrasonic or sonic level. With this aspect of predictive maintenance, friction and stress in a rotating machine can be heard.
Infrared analysis is very effective in detecting electrical and mechanical failures. It is taken to be the most cost effective technology today by some people.