In a predictive maintenance program, machines or assets are monitored to measure the current state of health. There are many different types of sensors that can be used for this task. However, it can be difficult to match the sensor to the application. In this article from Analog Devices, learn more about the various types of sensors and how to deploy them effectively.
After installation, an industrial motor exists on a health timeline - with motor failure being the end. Faults can be detected at various points in this timeline by different types of maintenance programs or sensors, from ongoing preventative maintenance to vibration sensing to temperature sensing to auditory sensing. In the following table, find out more about the types of sensors available and the types of faults they are best at detecting.
|
Measurement |
Sensor |
Key Information |
Target Faults |
|
Vibration |
Piezo accelerometer |
Low noise, frequencies up to 30 kHz, well established in CbM applications |
Bearing condition, gear meshing, pump cavitation, misalignment, imbalance, load condition |
|
Vibration |
MEMS accelerometer |
Low cost/power/size, frequencies up to 20 kHz+ |
Bearing condition, gear meshing, pump cavitation, misalignment, imbalance, load condition |
|
Sound pressure |
Microphone |
Low cost/power/size, frequencies up to 20 kHz |
Bearing condition, gear meshing, pump cavitation, misalignment, imbalance, load condition |
|
Sound pressure |
Ultrasonic microphone |
Low cost/power/size, frequencies up to 100 kHz |
Pressure leaks, bearing condition, gear meshing, pump cavitation, misalignment, imbalance |
|
Motor current |
Shunt, current transformer |
Low cost, noninvasive, usually measured at motor supply |
Eccentric rotors, winding issues, rotor bar issues, supply imbalance, bearing issues |
|
Magnetic field |
Hall, magnetometer, search coil |
Low cost/size, frequencies up to 250 Hz, stable over temperature |
Rotor bar, end ring issues |
|
Temperature |
Infrared thermography |
Expensive, accurate, multiple assets/sources of heat at one time |
Heat source location due to friction, load changes, excessive start/stop, insufficient power supply |
|
Temperature |
RTD, thermocouple, digital |
Low cost, size, accurate |
Change in temperature due to friction, load changes, excessive start/stop, insufficient power supply |
|
Oil quality |
Particle monitor |
Viscosity, particles, and contamination |
Detect debris from wear |
Historically, condition-based monitoring (CbM) systems have been based on sensors that are hard-wired into a central monitoring system. With the advent of wireless technology, though, CbM is poised to be installed and used more often due to the comparative ease of installation. Analog Devices has continually been at the forefront of sensor development, and has introduced new products to meet the demands of today’s production facilities.
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