1. Infrared Thermography
- A Predictive Maintenance Technology
Shivaji Choudhury

2. Predictive Maintenance Technologies
 Predictive maintenance attempts to detect
the onset of a degradation mechanism with
the goal of correcting that degradation prior
to significant deterioration in the component
or equipment.
 The diagnostic capabilities of predictive
maintenance technologies have increased in
recent years with advances made in sensor
technologies.

3. Predictive maintenance flow chart
1. Condition Monitoring
is a part of
Predictive
Maintenance.

4. Common predictive technology
applications (NASA 2000)

5. Thermography
 Thermal measurement technology
measures temperatures of key
equipment parts or areas being
monitored.
 Abnormal temperatures indicate
developing problems.

6. Technology
 There are two types of equipment used in
this technology.
 Contact methods of temperature
measurement, using thermometers and
thermocouples, are still commonly used for
many applications.
 non-contact measurement using infrared
sensors has become an increasingly
desirable alternative to conventional
methods.

7. Advantages of Non-Contact
Thermal Measurement
 • Target in motion .
 • Target electrically hot . Current-conducting
equipment and components
present a hazard to personnel and
instruments alike.
 • Target fragile .
 • Target very small .
 • Target remote .
 • Target temperature changing .

8. Infrared in the Electromagnetic
Spectrum

9. Infrared thermography (IRT) –
 Infrared thermography is based on
measuring the distribution of radiant
thermal energy (heat) emitted from a
target surface and converting this to a
surface temperature map or thermogram.
 Infrared thermography is the technique of
producing an image of invisible infrared
light emitted by objects due to their
thermal condition.

10. Non-Contact Temperature Measurement

11. Infrared Applications
1. Electrical
2. Mechanical
3. Commercial buildings
4. Miscellaneous

12. Infrared Applications -Mechanical
1. • Refractory
buildings (insulation,
air leakage, roofs)
2. • Reinforcing bar
location
3. • Underground leaks
4. • Steam traps
5. • Boiler tubes
6• Valves (leakage,
blockage)
7• Bearings
8• Couplings
9• Insulation (wet,
damaged, coverage)
10• Pipes (thin areas,
blockage, missing
lining)

13. Infrared Applications -Electrical
1. • Electrical connections
(loose/corroded)
2. • Switchyard disconnects
3. • Transformers
(connections, arrestors,
cooling)
4. • Transformers
(internals)
5. • Misaligned contacts,
brushes, fuses, fuse
clips, holders
6. • Splices, crimps
7. • Motor Control Center
(MCC)
8• Conductors (stranded,
undersized, damaged)
9• Inductive heating
(structure, bus ducts)
10• Batteries (connections,
cells)
11• Open circuits
(capacitors)
12• Load imbalance
13• Printed circuit boards
14• Motors (frames,
bearings, connections)
15. detecting electrical
deficiencies

14. Infrared Applications -Miscellaneous
1. Thermal plumes .
2. Commercial buildings.
3. Heat transfer evaluation of heat
exchangers .
4. Condenser tube leaks, condenser
vacuum leaks.
5. Boiler casing flue gas leaks.

15. Electrical Applications
 The primary use for infrared thermography,
and usually the most straightforward
application for it, is in the area of electrical
predictive maintenance. Within this area,
there are three main categories of
problems:
1. high electrical resistance.
2. Hot spots caused by inductive currents
3. open circuits.

16. Electrical - High Electrical Resistance
 High electrical resistance is the most common
problem that can be identified by using an
infrared imager. Based on Ohm’s law, power
(watts) is calculated as the square of the
current multiplied by the resistance (P = I2R).
When the resistance is high, the power that is
dissipated will be high.
 A higher power translates into a higher
temperature at the same location. This creates
the hot spots that are detected by the infrared
thermal imager.

17. Electrical Infrared Thermal Imaging
 The National Fire Protection Association -
NFPA© 70B 2010 states that infrared electrical
surveys should be performed on an annual
basis.

18. Power lines and Sub-stations

19. Electrical Applications:
Motor
Poor rotor or stator
winding condition shows
as heating of motor body.

20. Electrical Applications
 Transformer
Cold cooling fins
due to low oil level
in a transformer.

21. Electronics :Printed circuit board
 Typical reasons for
temperature hotspots
or deviations
1. Under designed
components
2. Component failure
3. Improper soldering
4. Broken traces
5. Reversed polarity

22. Mechanical Applications
 Friction
1. In the case of rotating or moving equipment, the result
of friction is readily observable as an increase in
temperature. Typical situations evolve in the area of
bearings on pumps and motors.
2. If a bearing or coupling is inadequately lubricated,
internal friction can cause heating, which can usually be
observed during operation.
 Valve Leakage /Blockage
1. The leakage of fluid past a normally closed valve might
be easy to observe with an infrared imager.

23. Mechanical Applications
Washer Fluid Pump
It appears the
coupling has failed
or is out of
alignment.

24. Mechanical Applications
Conveyer Belt
 Seized conveyer belt roller as indicated by
elevated temperatures in belt/roller contact
area.

25. Thermal imaging :Heating, self-combustion
monitoring coal stock

26. Mechanical Applications
 Steam Traps
Leakage from a
steam trap.

27. Infrared Applications -Mechanical
Insulation
 Insulation on piping and equipment can
be tested for integrity using an infrared
imager.
 IR applications include the assurance of
complete coverage of the area,
thinning/degradation of the insulation,
and wet insulation.

28. Commercial Buildings
1. Buildings can be
inspected for energy
conservation with
an infrared imager.
2. Typical problems
that can be found
include HVAC ,air
infiltration or
exfiltration, poor
insulation, and wet
roofs.
 Roof inspection

29. Thermal Plume Detection
 The use of an infrared imager in a
helicopter or airplane can assist the plant in
verifying thermal discharge patterns in
cooling ponds or other bodies of water. The
thermal plume, or outfall, is easily
observed from the air.
 The hottest spots on the surface of the
water are easily located. This facilitates
routine environmental monitoring for
thermal discharge.

30. Correlation of thermal analysis with
other technologies
Technology Correlation
method
indication
vibration Time coincident Increasing or already high
vibration at the same time as
increasing temperature
lubrication Time sequence High and or increasing large
wear particles
Debris
analysis
Time sequence Damage has occurred or is
occurring
Leak
detection
Time coincident Abnormal temperature
coincident with acoustic
signals indicating internal leak
of gas or fluid
Electric
circuit
testing
Time coincident High resistance in energized
circuit radiating abnormal heat

31. THANKING YOU