Better Predictive Maintenance Through Vibration and Thermal Sensing

Variable-capacitance accelerometers will deliver stable and accurate measurement, including the measurement of low-frequency vibration. They can also operate over a wide range of temperatures.

Such accelerometers are often built as microelectromechanical systems (MEMS) and are widely used for structural monitoring and constant acceleration measurements. They have a wide range of applications, measuring acceleration, deceleration, or force, making them good monitors of many kinds of mechanical devices and activities.

Predictive Maintenance and Piezoelectric Devices

Rugged and reliable piezoelectric (PE) devices have been a mainstay of vibration monitoring for a long time. Piezoelectric crystals, typically made from lead zirconate titanate, generate power, simplifying their employment in many use cases. They’re tolerant of a wide temperature range and operate at up to approximately 20 kHz.

Flexure-, compression-, and shear-type piezo accelerometers (relative to the structure of the piezo material) each have characteristics that make them more or less appropriate for different tasks.

Temperature sensing has an obvious role, but it may be subject to considerable variation depending on changing ambient conditions or shifts in operating conditions (e.g., processing different types of materials that may consume different amounts of power).

In addition to discrete temperature sensors, infrared thermography may present an opportunity to quickly build knowledge of a system or machine and its operational characteristics as well as potential trouble spots. For instance, multiple heat sources in close proximity and inadequate or failing ventilation could be easily identified with thermal imaging.

This information could be maintained as a map, and changes in that map can be monitored over time and correlated to failure points.

Electronic Analysis to Illuminate Vibration Monitoring

Monitoring power circuits, especially those involved with operating electrical motors, solenoids, etc., can reveal much about the health of the equipment. This can also deliver helpful time-series data of value in preventive maintenance and it’s relevant to understanding the source and cause of vibration issues in combination with other data sources.

To achieve success with vibration monitoring, fidelity and frequency response are vital. Simply recognizing the presence of vibration is of limited value unless that vibration can be analyzed and traced to a source. A key factor is employing sensors that can accurately detect and characterize vibration across a wide range of frequencies to identify all of the contributing factors (see figure).