Chauvin Arnoux 1875 User manual

GB – User’s Manual
Thermography bench
C.A 1875

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You have just purchased a C.A 1875 thermography tutorial bench and we thank
you for your confidence.
For best results from your instrument:
•read these operating instructions carefully,
•observe the precautions for use
MEANINGS OF THE SYMBOLS USED
Selective sorting of wastes for the recycling of electrical
and electronic equipment within the European Union.
In accordance with directive WEEE 2002/96/EC: this
equipment must not be processed as household waste.
Possible hazard. Refer to the operating instructions before
using the device.
The CE marking guarantees conformity with European
directives and with regulations concerning EMC.
Attention, hot surface
PRECAUTIONS FOR USE
If this device is damaged or a part is missing, please immediately contact the seller.
Non-observance of the instructions or of the precautions for use may impair the
protection provided by the device.
Refer to these instructions concerning each danger symbol encountered.

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CONTENTS
1. INTRODUCTION ...............................................................................................4
2. PRESENTATION ...............................................................................................5
3. CHARACTERISTICS ...........................................................................................7
3.1 GENERAL CHARACTERISTICS OF THE BENCH ........................................................ 7
3.2 CHARACTERISTICS OF THE FUSE........................................................................ 8
4. COMMISSIONING ............................................................................................8
5. MANIPULATIONS ............................................................................................9
5.1 THERMAL TRANSFERS.............................................................................. 9
5.1.1 Theory.............................................................................................. 9
5.1.2 Manipulations: study of the influence of emissivity ...................... 15
5.2 STUDY OF THE REAL BODY............................................................................. 16
5.2.1 Theory............................................................................................ 16
5.2.2 Manipulations: study of the influence of reflection and transmission
....................................................................................................... 18
5.3 OPTICS AND THERMOGRAPHY CAMERA................................................ 18
5.3.1 Theory: study of the spatial resolution. ......................................... 18
5.3.2 Manipulation: study of spatial resolution...................................... 22
5.4 MANIPULATIONS ON SOFTWARE .......................................................... 23
5.5 THERMOGRAPHY IN PRACTICE .............................................................. 25
5.5.1 Fault determination modes. .......................................................... 25
5.5.2 Applications ................................................................................... 26
5.6 PRODUCING A Q19 REPORT .......................................................................... 28
5.6.1 Presentation .................................................................................. 28
5.6.2 Application..................................................................................... 31
6. MAINTENANCE..............................................................................................31
6.1 REPAIR ..................................................................................................... 31
6.2 CHANGE OF FUSE ................................................................................... 32
7. WARRANTY ...................................................................................................32
8. TO ORDER .....................................................................................................32
APPENDIX 1: DETERMINATION OF EMISSIVITY..................................................33
APPENDIX 2: DETERMINATION OF REFLECTED TEMPERATURE..........................34
APPENDIX 3: APPLICATION EXERCISES ..............................................................35
APPENDIX 4: SOLUTIONS ..................................................................................41

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1. INTRODUCTION
Infrared thermography detection technology has become an essential means of
guaranteeing the safety of industrial production conditions. It is used in sectors of
industry as varied as metallurgy and steel-making, electric power, the oil industry,
automation, the extraction of natural gas, the transport industry, and other
professions active in fire fighting and border surveillance. In all of these activities,
characterized by just-in-time operating procedures, production equipment at high
voltage, powerful electric currents, or high operating speeds, infrared thermal
imaging can be a useful contact-free real-time inspection method.
This detection method requires no breaking of current, no stopping of machines or
interruption of production. It can diagnose latent defects in advance, and so
forestall the occurrence of malfunctions and prevent production incidents. Thermal
imaging is an innovative "contact-free" evaluation technique that is all at once safe,
reliable, and rapid.
A thermal camera does not measure temperatures, but radiant fluxes. After the
adjustment of a few parameters by the thermography operator, the camera
calculates the temperatures of the target. It then gives the user a map of the
temperatures, or "thermogram": each temperature is represented by a colour.
Here are two examples of thermograms:
Inside views of three-phase electrical boxes
First of all, we can see that these two thermograms are practically identical: we
observe one phase that is hotter than the other two (the one on the left in the left-
hand thermogram, the top one in the right-hand thermogram). As it happens, their
colour is light yellow, which indicates according to the colour scale to the right of
the IR image that the temperature is higher there.
Let's take a closer look at these two images, by inserting temperature cursors.
Left-hand thermogram:
-Cursor 1: 52.9°C
-Cursor 2: 44.9°C

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In accordance with the rules of classical thermography (see below), there is no
particular problem.
Right-hand thermogram:
-Cursor 1: 60.3°C
-Cursor 2: 35.3°C
In this case, the temperature difference is 25°C! We can conclude that there is a
real problem in the installation and corrective action must be taken.
In conclusion, it is necessary to pay attention to the colour scales and to perform a
genuine analysis. Dark means colder and light means hotter, but that does not
mean that there is a problem to be detected! Bear in mind that the camera is a
measurement tool and that the investigations must be continued!
2. PRESENTATION
Growing demand for training in infrared thermography has led CHAUVIN ARNOUX
to develop measurement equipment specially designed for instructional purposes.
Far from being exhaustive, the manipulations proposed are intended only to
illustrate, through a few examples, the false measurement records it is possible to
produce in infrared thermography.
The objective is to make people aware that an infrared camera is a precision
measurement tool that requires much training and experience to use correctly.
The C.A 1875 tutorial bench comprises a hot plate with several targets having
different surface conditions and made of different materials, along with test screens
that are affixed to the front of the bench using magnets. (See the diagram below).
The purpose of this bench is to allow the student to discover the main possible
causes of error when making a measurement using an infrared camera.
This equipment can be used to perform the following experiments:
-Problem of emissivity of the materials
-Problems of positioning
-Problem of reflection
-Problem of transmission
-Problem of spatial resolution

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Presentation of the C.A 1875 thermography tutorial bench:
1: Hot plate
2: LEDs indicating rising or falling temperature
3: On / Off switch
4: Power cord connection
5: Fuse compartment
6: 10: Plates of different materials
7: Cover protecting the bench
8: Test screen attachment plate
9: Black reference plate for the various tests
10
9
8
7
6
5
4
3
2
1

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Presentation of the test screens
Test screen no. 1:
Plexiglas pane
Presentation of the hot targets
3. CHARACTERISTICS
3.1 GENERAL CHARACTERISTICS OF THE BENCH
Power supply: 230 V
50 / 60 Hz
Consumption: 400 mA
Temperature of hot plate: 50 to 55°C ±3°C
Dimensions: 280 x 225 x 110 mm
Weight: 1.8 kg
Black plate having an
emissivity of 0.95
Plate 6:
Aluminium
Plate 4:
Red copper
Plate 3:
Laminate
Plate 2:
Stainless steel
Plate 1:
Polish steel
Test screen no. 2:
Slits of variable width
Plate 5:
Brass

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Environmental conditions:
Indoor use:
0 to 40°C and 10 to 90% RH
Altitude less than 2000 m
Degree of pollution 2
Storage:
-20 to + 65°C and 10 to 90% RH
Altitude less than 12,000 m.
NB: storage at a higher temperature is possible but requires manually resetting the
safety thermostat to render the device functional.
Conformity to international standards:
- Safety as per IEC 61010
- EMC as per IEC 61326-1
3.2 CHARACTERISTICS OF THE FUSE
Dimensions: 5 x 20 mm
Rating: 0.5 A fast-blow – 250 V
4. COMMISSIONING
The C.A 1875 thermography tutorial bench must be placed on a flat, level
surface. The hot plate must be perpendicular to the work top.
Once the bench is in place, connect it to a mains outlet with an earth and power up
using the On/Off button.
Wait a few minutes for the plate to warm up before running the first tests.

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Diagram of operation of the LEDs and of the temperature variation of the hot plate.
When the bench is started up, L1 lights until the plate reaches approximately 55°C.
When this temperature is reached, L2 lights and the plate cools to approximately
50°C. Heating resumes, with the lighting of L1, and so on. This cycle continues
indefinitely for as long as the bench is in operation.
5. MANIPULATIONS
Look up the operating instructions for the use of the RayCAm.
Before any new manipulation, create a new thermogram recording folder.
During the manipulations, save as many images as possible.
5.1 THERMAL TRANSFERS
5.1.1 Theory
To correctly understand the events involved, it is important to know the phenomena
that underlie evolutions or changes of temperature.
There are three thermal transfer modes:
-Conduction
-Convection
-Radiation
These three modes can be present simultaneously, independently of one another.
A heat flux is a quantity of thermal energy per unit of time. A transfer flow occurs
only when there is a temperature difference. Thermal energy is transferred from a
hot body to a cold body.
It is necessary first of all to understand the thermal phenomena involved.
L1 L2
T(°C)
Ta
Regulation
t
60° Max

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Conduction.
In physics, thermal conductivity is the parameter used to quantify the ability of a
body to conduct heat. It represents the quantity of heat transferred per unit of area
and per unit of time under the action of a temperature difference between the two
ends of a sample of the body, and therefore in the presence of a temperature
gradient.
Consider the example of a metal bar that is heated at one of its ends: the thermal
agitation of the atoms located at the heated end of the bar increases and is
transmitted step by step in the direction opposite the thermal gradient.
Application: see Appendix 3, exercise 1
Convection.
A flow or circulation of a liquid or gas can transport with it a certain quantity of
thermal energy. This transport of heat is called thermal CONVECTION. In
convection, the heat uses the fluid as a vehicle to convey it. There are two types of
convective transfers:
-Natural convection: when there is a temperature difference between two
points in a fluid, the hot fluid tends to rise because of its buoyancy. This
creates a natural circulation of the fluid under the effect of the heat, which
is then transported by it: this is called natural convection.
Thermal gradient
Temperature rise at the end of the bar