Understanding Infrared Thermography Reading 7 Part 2 of 2.pdf

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6.1.12 Equipment Matrix The equipment to be surveyed, the selection criteria, and the locations and frequency of inspection should be compiled in a matrix. Typically, the electrical equipment is grouped together, as are the other major component groups. An alternate approach would be to list the equipment in a route of survey-format, which might save time for the infrared thermographer. 6.1.13 References References to any helpful information should be provided. These typically include training materials, textbooks on the subject, and equipment operation manuals. Charlie Chong/ Fion Zhang
EPRI Licensed Material Basic Elements of an In-House Program 6.2 Sample Program This section incorporates the above recommendations and could serve as the basis for a program using infrared thermography as part of a predictive maintenance program. 1.0 INTRODUCTION 1.1 This program is for the administration and conduct of an infrared inspection program of electrical and mechanical equipment. The purpose of this program is to identify equipment that requires maintenance and to improve its reliability through the use of infrared thermography (IR). 1.2 This document contains the recommended scope, frequency, and corrective action criteria for routine and unscheduled infrared surveys. 1.3 Requests for changes to this program and questions relative to it shall be directed to the administrator of the IR program. 2.0 DEFINITIONS 2.1 Infrared – Electromagnetic radiation having wavelengths that are greater than those of visible light, but shorter than microwaves. As it applies to IR thermography, the wavelengths are between 3 to 15 micrometers. 2.2 Infrared Survey – A comprehensive examination of components and equipment with an infrared imaging system. 2.3 Emissivity – The ratio of radiance from a surface to the radiance at the same wavelength from a perfect blackbody at the same temperature. Functionally, this is the radiation efficiency of a surface in the infrared spectrum. 2.4 Radiosity – Thermal energy of a surface as seen by the infrared detector. 2.5 Thermogram – A recorded, displayed, or hard-copy image of the output of an infrared imaging system. 2.6 Isotherm – A thermal contour on a thermogram where all of the spots along it are at the same apparent temperature. 2.7 Infrared thermographer – An individual who is trained and qualified to operate infrared imaging equipment and to interpret the images. 3.0 SCOPE 3.1 The requirements of this procedure shall apply to all safety-related components. It shall also be applicable to non-safety-related equipment where financial benefit might be achieved by monitoring (that is, increased plant availability, decreased maintenance costs, and so on). 3.2 This procedure includes guidelines for the following: • Component selection 6-5
Page 1 and 2: Infrared Thermal Testing Reading VI
Page 3 and 4: 6.1 Basic Elements An in-house prog
Page 5 and 6: 6.1.4 Responsibilities This section
Page 7 and 8: IR Viewing Window - Opaque Polymer
Page 9 and 10: 6.1.8 Acceptance Criteria All surve
Page 11 and 12: 6.1.9 Reporting Criteria A rigid pr
Page 13: 6.1.10 Qualification of Personnel P
Page 17 and 18: EPRI Licensed Material Basic Elemen
Page 25 and 26: 7. TRAINING AND CERTIFICATION This
Page 27 and 28: Recommended training and certificat
Page 29 and 30: ■ Level II A Level II infrared th
Page 31 and 32: The experience and education recomm
Page 33 and 34: B. Spatial Resolution • the conce
Page 35 and 36: D. Equipment Operation • Be able
Page 37 and 38: The PdM basic examination is more s
Page 39 and 40: Appendix-A The Science Of Thermogra
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Page 43 and 44: A.2.1 Heat and Temperature What is
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Page 47 and 48: A.2.3 The Three Modes of Heat Trans
Page 49 and 50: The Fourier Conduction Law: Q/A Q =
Page 51 and 52: A.2.5 Convection Convective heat tr
Page 53 and 54: Figure A-2 Convective Heat Flow Cha
Page 55 and 56: A.2.6 Radiation Radiative heat tran
Page 57 and 58: A.2.7 Radiation Exchange at the Tar
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Page 61 and 62: Figure A-4 Radiative Heat Flow W ε
Page 63 and 64: A.2.8 Specular and Diffuse Surfaces
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Specular or Diffuse Surfaces Diffus
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Specular and Diffuse Surfaces Confu
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Specular reflection is the mirror-l
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Reflections off Specular and Diffus
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The thermogram of the outside surfa
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Steady-state conduction Steady stat
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A.3 The Basic Physics of Infrared R
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A.3.1 Some Historical Background Th
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A.3.3 The Target Surface The chart
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Figure A-6 shows the distribution o
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Charlie Chong/ Fion Zhang
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Two physical laws define the radian
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According to (2), the wavelength at
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Figure A-7 Spectral Distribution of
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Figure A-8 shows that the instrumen
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If the emissivity of a gray body is
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Under certain conditions, an error
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EXAM score! Non-graybody (colored b
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Figure A-10 illustrates the spectra
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Figure A-10 Infrared Transmission o
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Figure A-11 Infrared Spectral Trans
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Figure A-11 shows transmission curv
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EXAM score! Glass is opaque λ > 5
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Figure A-12 Characteristics of IR T
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The characteristics of the window m
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IR Lenses - LWIR Len Charlie Chong/
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IR Lenses - Fresnel Len Charlie Cho
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Figure A-13 Components of an Infrar
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Infrared optics are available in tw
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All infrared detector-transducers e
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Figure A-14 Typical Infrared Radiat
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Germanium Len Charlie Chong/ Fion Z
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Thermopile Detector Charlie Chong/
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The IR Detectors Infrared detectors
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Figure A-15 Spectral Sensitivity of
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The Mercury- Cadmium-telluride (Hgc
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The Mercury- Cadmium-Telluride (HgC
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Point-sensing instruments for measu
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A.3.6.1 Line Scanning The purpose o
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A.3.6.2 Two-Dimensional Scanning Th
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Opto-mechanical Scanner A typical c
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Electronic scanning Electronic scan
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Figure A-18 Schematic of a Typical
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Applications for infrared FPAs incl
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Staring Charlie Chong/ Fion Zhang
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A.4.1 Point-Sensing Instruments For
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Temperature sensitivity is also cal
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EXAM score! thermal resolution (≠
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NETD - Noise Equivalent Temperature
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Figure A-19 Instrument Speed of Res
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Figure A-20 Fields of View of Infra
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Figure A-20 Fields of View of Infra
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The output requirements are totally
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Spectrally selective instruments em
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Figure A-21 Spectral Filtering for
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Figure A-22 shows a similar solutio
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A.4.2 Scanners and Imagers.Qualitat
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• Total field of view (TFOV): the
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Despite some manufacturers’ claim
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A.4.3.1 Temperature Sensitivity, Mi
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Figure A-23 Test Setup for MRTD Mea
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A.4.3.2 Spot Size (FOV) , Instantan
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■ A standard 4 bar (slit) resolut
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Both MRTD and MTF are functions of
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IFOVmeas: The slit width at which t
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FPA Charlie Chong/ Fion Zhang http:
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FPA Charlie Chong/ Fion Zhang
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A.4.3.3 Speed of Response and Frame
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A.4.4 Thermal Imaging Software In o
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The newest field-portable instrumen
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Appendix B Measuring Emissivity, Re
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Figure B-1 Target Radiosity Charlie
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The reference emitter technique wor
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1. Apply the reference emitter (E)
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B.2.2 Reflective Emissivity Techniq
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Figure B-3 Using the Reflective Emi
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Figure B-4 Using the Transmittance
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Appendix C Quick Reference Charts A
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MTF Determination Using An Ir Image
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Measuring And Setting Effective Emi
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Classification Of Faults (Guideline
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Reading: Four Emissivity: Understan
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Figure 1 shows a typical three-phas
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Figure IR1: Corresponding infrared
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Thermal radiation and properties of
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The thermal nature of materials. Ma
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So in plain English, when the therm
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Figure 2: Stainless steel block. (a
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Observed with our thermal imager (w
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Can you see my eye glasses in the i
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How can the thermal imager’s read
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When we remove the block from the o
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In this experiment we see that the
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Charlie Chong/ Fion Zhang http://ww
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Using a narrow band filter to measu
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Emissivity, the variable’s variab
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Emissivity and electrical equipment
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In manufacturing processes, steel o
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In this case, we have another power
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Figure IR1: Corresponding infrared
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Figure 7: Measuring the loads on a
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Summary Predictive maintenance PDM
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It is much like most endeavors in l
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Good Luck Charlie Chong/ Fion Zhang
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Charlie https://www.yumpu.com/en/br
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