- A Predictive Maintenance Technology
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
The diagnostic capabilities of predictive
maintenance technologies have increased in
recent years with advances made in sensor
Predictive maintenance flow chart
1. Condition Monitoring
is a part of
Common predictive technology
applications (NASA 2000)
Thermal measurement technology
measures temperatures of key
equipment parts or areas being
Abnormal temperatures indicate
There are two types of equipment used in
Contact methods of temperature
measurement, using thermometers and
thermocouples, are still commonly used for
non-contact measurement using infrared
sensors has become an increasingly
desirable alternative to conventional
Advantages of Non-Contact
• Target in motion .
• Target electrically hot . Current-conducting
equipment and components
present a hazard to personnel and
• Target fragile .
• Target very small .
• Target remote .
• Target temperature changing .
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
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
1. high electrical resistance.
2. Hot spots caused by inductive currents
3. open circuits.
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
Poor rotor or stator
winding condition shows
as heating of motor body.
Cold cooling fins
due to low oil level
in a transformer.
Electronics :Printed circuit board
Typical reasons for
1. Under designed
2. Component failure
3. Improper soldering
4. Broken traces
5. Reversed polarity
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.
Washer Fluid Pump
It appears the
coupling has failed
or is out of
Seized conveyer belt roller as indicated by
elevated temperatures in belt/roller contact
Leakage from a
Infrared Applications -Mechanical
Insulation on piping and equipment can
be tested for integrity using an infrared
IR applications include the assurance of
complete coverage of the area,
thinning/degradation of the insulation,
and wet insulation.
1. Buildings can be
inspected for energy
an infrared imager.
2. Typical problems
that can be found
include HVAC ,air
insulation, and wet
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
Correlation of thermal analysis with
vibration Time coincident Increasing or already high
vibration at the same time as
lubrication Time sequence High and or increasing large
Time sequence Damage has occurred or is
Time coincident Abnormal temperature
coincident with acoustic
signals indicating internal leak
of gas or fluid
Time coincident High resistance in energized
circuit radiating abnormal heat