Predictive maintenance (PdM) is the servicing of equipment when it is estimated that service is required, within a certain tolerance. PdM is used in railroads, industrial equipment, manufacturing plants and oil and gas processing.
Maintaining machinery and electronics is most cost-effective if done when it is needed. To that end, predictive maintenance systems are designed to ensure that servicing doesn't happen too soon, wasting money on unnecessary work, or too late, after wear and time have caused undue deterioration. PdM systems can also help plan an inventory for replacement parts and provide input on systems that need a design upgrade because of unacceptable performance.
PdM is enabled by the advances in sensor and communication technologies that are part of the ongoing trends of automation and the Internet of Things (IoT), and particularly the Industrial IoT. Those advances enable continuous monitoring and data analytics for mechanical and electrical conditions, operational efficiency and other performance indicators.
PdM works through the use of sensors, often tied together with PdM software on a wireless sensor and actuator network (WSAN). The software takes into account time, mileage or usage and the measured, sometimes minute changes from sensors that can indicate a need for service before reduced performance or degradation of the equipment occurs. These measurement are often performed on machines while they are running to reduce impact on production.
Many measurements are taken to estimate the need for service, including:
- Oil and oil contaminant analysis.
- Sound and ultrasound analysis.
- Vibration analysis.
- Infrared analysis.