Predictive Maintenance with Infrared Thermography
Predictive Maintenance
A technique to predict the future point of failure of a machine component so that the component can be replaced, based on a plan, just before it fails.
Predictive Maintenance Organization
This technique involves measuring various parameters that show a predictable relationship with the component’s life cycle. Examples of these parameters are:
- Vibration of bearings
- Temperature of electrical connections
- Insulation resistance of a motor’s coil
Monitoring
The objective is to review common condition monitoring techniques for general selection. Monitoring indicates the machine’s condition or health status, enabling safe and economical operation and maintenance.
Inspection Methodology
Once predictive maintenance feasibility is determined, the next step is to identify and control physical variables indicative of the machine’s condition.
Monitoring Machines
Monitoring indicates when a problem exists. It must distinguish between good and bad condition, and if bad, show the severity.
Machine Guarding
Its purpose is to prevent catastrophic failure. When values indicating machine status reach dangerous levels, the machine automatically stops.
Fault Diagnosis
Its purpose is to define the specific problem. Predicting life expectancy aims to estimate how long the machine could operate without the risk of catastrophic failure.
Thermography
This technique allows accurate, non-contact temperature measurement. It captures infrared radiation.
Discovery of Infrared Rays
Sir Frederick William Herschel (1738-1822), a musician and astronomer, emigrated to England in 1757. He and his sister Caroline constructed telescopes. Herschel passed sunlight through a crystal prism to create a spectrum (a rainbow). He then measured each color’s temperature using three thermometers with blackened bulbs to better absorb heat.
Applications of Thermography
Infrared cameras are indispensable in predictive and preventive maintenance. They detect anomalies invisible to the human eye, preventing costly errors. Applications include transformers, engines, connector lines, and liquid storage tanks.
Infrared Cameras
- Easy to use as a video camera
- Provide a complete picture of the situation
- Perform inspections with systems operating under load
- Identify and locate problems
- Measure temperature
- Store information
- Indicate necessary steps
- Find problems before they occur
- Save valuable time and money
How an Infrared Camera Works
An infrared thermal imaging camera detects infrared energy (heat) without physical contact, converting it into an electronic signal. This signal is processed to produce a television picture or video, and calculates temperature.
Why Use Infrared Thermography?
Infrared thermography has wide-ranging applications. Examples include:
- High-temperature elements: furnaces, evaporators, boilers, etc.
- Dangerous elements: corrosive or toxic elements, such as salt baths for heat treatment.
- Temperature-controlled environments: cold rooms, laboratories.
- Low-voltage electrical elements (medium and high voltage): power lines, insulators, capacitors, switches, switchgears, power transformers, power generators, motors, and control cells.
- Mechanical devices: engines, rolling mills, air compressors, pumps, machine tools, and dies.
- Electronics: power transistors or thyristors, communication transmitters, waveguides, coaxial cables, variable frequency drives, motors, and rectifiers.