Introduction to Indoor Electrical[2]

Introduction to Indoor Electrical Equipment Inspection

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1©2009 FLIR Systems, Inc. All rights reserved. Intended solely for use by FLIR/ITC distributors, customers and prospects only.

Indoor Electrical


Infrared Training Center

Global Leader in IR Thermography Training. ISO-9001 Registered and NETA accredited in IR Thermography Training. Level I, II and III Condition Monitoring IR Certification, R&D Courses, and Application Courses.


Your Presenter

• Jay Bowen• Electrician/ Engineer 32 years• Thermographer 15 years –

Level III• Master Electrician - Wisconsin• Certified Electrical Inspector -

Wisconsin• Designer of Electrical Systems

- Wisconsin• Associate Degree Electronics

Technology• Electrical Contractor -

Previous Business owner

• Green Bay, Wisconsin• Packer Fan (season ticket

holder),



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Electrical Safety Requirements

• NFPA 70E (National Fire Protection Association):”Electrical Safety Requirements for Employee Workplaces”

• Details OSHA 1910 Requirements


NFPA 70E

• Electrical Safety Training• Approach Limits• Flash Hazard Analysis per NFPA 70E-2000, Part

II 2-1.3.3 • Personal Protective Equipment (PPE)

• Face shields• Body protection from arc flash


Existing Standards

• NETA 2007 - Acceptance Testing Specifications for Electrical Power Distribution Equipment and Systems

• NEMA MG-1 - Information Guide for General Purpose Industrial AC Small and Medium Squirrel-Cage Induction Motor Standards

• NFPA 70B - Recommended Practice for Electrical Equipment Maintenance

• NFPA 70 – National Electrical Code – Table 310 -13 Wire insulation temperatures

• NFPA 70E - Electrical Safety in the Workplace



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Existing Standards

• ASNT SNT-TC-1A- [(2001)],” Recommended Practice for Training and Certification Non-Destructive Testing”

• ASTM E1934.2050-1 Examining Electrical and Mechanical Equipment with Infrared Thermography

• ASTM E1933.4671-1 Measuring and Compensating for Emissivity Using Infrared Imaging Radiometers

• ASTM E1897.4369-1 Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers

• ASTM E1862.3882-1 Measuring and Compensating for Reflected Temperature Using Infrared Imaging Radiometers

• ASTM E1213 - 97(2009) Standard Test Method for Minimum Resolvable Temperature Difference for Thermal Imaging Systems

• ASTM E1311 - 89(2004) Standard Test Method for Minimum Detectable Temperature Difference for Thermal Imaging Systems

• ASTM E1256 - 95(2007) Standard Test Methods for Radiation Thermometers (Single Waveband Type)


Criteria

• One size does not fit all• Must have more than just temperature

measurements• Component• Load or amperage• Season• Time of day• System Importance

• Accuracy of temperature• Emissivity • Angle• Trefl• Distance• Resolution

• Direct and indirect tables


NETA

Temperature difference (ΔT) based on

comparisons between similar components

under similar loading.

Temperature difference (ΔT) based upon

comparisons between component and ambient

air temperatures. Recommended Action

2ºF - 5ºF 2ºF - 18ºF Possible deficiency; warrants investigation

5ºF - 27ºF 18ºF - 36ºF Indicates probable deficiency; repair as time permits

- - - - - - 36ºF - 72ºF Monitor until corrective measures can be accomplished

>27ºF >72ºF Major discrepancy; repair immediately

*** Metric Challenged ***



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Criteria

• Load is very important -- heating with low load is very serious

• Equipment designation -- key equipment should have tighter criteria

• Circuit consideration -- critical nodes should have tighter criteria

• Time of use or cycle – how is this used and when

• Heat transfer effects -- wind, ambient or environment, location these are not considered in most criteria

• Indirect Measurements – how critical are these?


An Example

Problem= 133

Reference=87

Or…

Delta = 46

Make this a monitor.


An Example

Problem= 126

Reference=85

Or…

Delta = 41

Make this a monitor.

Wrong!!!

This is serious!



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Preparing for an IR Survey

• Routes are set up and routinely done to satisfy the requirements driven by the Equipment Listing and Schedule

• Often, Level I thermographers are given responsibility to perform IR surveys on a route basis

• We also recommend doing “IR by walking around” as about 10% of your routine surveys

• Someone authorized to open cabinets, etc should accompany the thermographer

• A method to collect the data


Routine Survey

• Systematically look at all “IR sensitive” components• These are the components determined by

the results of the Equipment List and Schedule study

• The survey will normally be categorized by • Equipment type• Location• Time to do the survey

• This all rolls up into an “IR Route”


Other Tips and tricks

• Compare, compare, compare• Stand still when looking at your thermal

or visual image• Large warm targets may indicate a more

severe problem than smaller hotter targets—Area matters!



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Where to Start

• Begin at service entrance • Recommend IR windows for over 600 volts.• 600 volts and under, you can often remove covers with

proper PPE and safety considerations.• Look at bolted connections, terminations, bolted

pressure switches.


facility electrical

• Power distribution. • Panel boards, bus ducts, dry type transformers, tap/splice boxes.

• Disconnect switches• Fusible/non-fusible. Remove cover, if possible

• MCCs (Motor Control Centers)• Open the buckets, or use IR windows


Normal Heating

Motors



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Localized Heating

Motors


Motors

TABLE 1

Insulation System Class A B F HTemperature Rating in Degrees Centigrade / Fahrenheit

105°C/221°F 130°C/266°F 155°C/311°F 180°C/356°F

Temperature Rise Allowance by Resistance (Based on 40°C(104F) / Ambient Temperature)

All Motors with 1.15 Service Factor(Hot Spot Allowance)

70(158)*

90(194)*

115(239)* —

Totally Enclosed Fan Cooled Motors(Hot Spot Allowance)

60(140)(5)

80(176)(10)

105(221)(10)

125(257)(15)

Totally Enclosed Non-Ventilated Motors(Hot Spot Allowance)

65(149)(0)

85(185)(5)

110(230)(5)

135(275)(5)

Motors other than those listed above(Hot Spot Allowance)

60(149)(5)

80(176)(10)

105(221)(10)

125(257)(15)

* When operating at service factor loading the hot spot temperatures can actually exceed the insulation rating resulting in shortened motor life.

Insulation Code


Motors

Comparison



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Controller

78.3°F

228.6°F

100

150

200

Ref Temp: 103.0°F

Max Temp: 241.7°F

Overload screw loose


Panel Boards

Termination


Panel Boards

Breaker Heating



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Panel Boards

Load correction software


Panel Boards

Bus Compression Connection


Clip Tension

Fuses / Switches



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Blade Mating

Fuses / Switches


20.6°F

650.9°F

200

400

600

Reference: 114°F

Anaylsis: >1076°F

Termination Failure

Breakers


Connection Torque

Breakers



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Harmonics

Transformers


Low Oil

Transformers


Connection Torque

Bus ways / Buss duct



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73.8°F

83.5°F

74

76

78

80

82

81.7°F

74.9°F

Bus ways / Buss duct


82.7°F

105.6°F

85

90

95

100

105

99.5°F

91.5°F

Improper Conductor Size

Conductors / Terminations





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161.4°F

391.6°F

200

250

300

350291.8°F

395.1°F

Improper Crimp



70.4°F

132.0°F

80

100

120

132.8°F

87.6°F

Improper Tightening



Cell Breakdown

Capacitors / Batteries



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77.0°F

136.0°F

80

100

120

Reference: 87.8°F

Anaylsis: 136.1°F

Capacitors / Batteries


Common Item


Tools

First Surface Mirrors

Anemometer

Phasing meter

MultimeterTach or RPM

Power Quality Ammeter

Motor Tester



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Reporting


Reporting

• EPRI lists the following for an effective report• Time/date• Equipment identification• Location• Specific problem• Corrective action• Visible light image• Infrared image• Inspector’s name and signature• Component temperature • Acceptance criteria • Ambient temperature • Site Conditions• Equipment load (for electrical equipment),• IR camera and lens


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Introduction to Indoor Electrical[2]

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