We compared the photometric and radiometric quantities in the visible, ultraviolet, and infrared spectra of white light-emitting diodes (LEDs), incandescent light bulbs and a compact fluorescent lamp used for home illumination. The color-rendering index and efficiency-related quantities were also used as auxiliary tools in this comparison. LEDs have a better performance in all aspects except for the color-rendering index, which is better with an incandescent light bulb. Compact fluorescent lamps presented results that, to our knowledge, do not justify their substitution for the incandescent light bulb. The main contribution of this work is an approach based on fundamental quantities to evaluate LEDs and other light sources.
The calorimetric method has for a long time been applied for losses measurement and energy conversion efficiency
determination in electrical machines. The number of temperature sensors necessary for its successful application in the
field constitutes in one of the major drawbacks of the method. The present paper shows how the usage of infrared (IR)
thermal imaging techniques can reduce costs and the necessary time for the calorimetric method application.
In recent years Brazil has experienced extraordinary growth despite the recent economic global crisis. The demand for
infrared thermography products and services has accompanied this growth. Like other non-destructive testing and
inspection, the results obtained by thermography are highly dependent on the skills of thermographer. Therefore, it is
very important to establish a serious and recognized process of certification to assess thermographers' qualifications and
help services suppliers to establish credibility with their customers and increase the confidence of these costumers on the
quality of these services.
The Brazilian Society of Non-Destructive Testing and Inspection, ABENDI, a non-profitable, private technical-scientific
entity, recognized nationally and internationally, has observed the necessity of starting a process for certification of
thermographers in Brazil. With support of a work group composed by experts from oil and energy industries,
transportation, universities and manufactures, the activities started in 2005.
This paper describes the economic background required for installation of the certification process, its initial steps, the
main characteristics of the Brazilian certification and the expectation for initiating the certification process.
An alternative model to determine the wind influence from themographic inspections is addressed in this paper. A wind
velocity dependent temperature reduction factor is developed and applied in order to estimate the target temperature in
the absence of wind. The model makes use of only two unknown coefficients, which are identified for each case. Tests
were conducted in laboratory using an aclimatiezed chamber developed to simulate actual conditions, as well in the field.
The results of application were also compared to those obtained from other researchers, showing very good agreement.
This paper presents some difficulties encountered when evaluating information from infrared thermal inspections conducted in uncovered power substations. Procedural, technical and environmental are the main factors of influence identified. Based on field data and in laboratory tests, preliminary mathematical models are derived, which are suitable either to forecast the system behavior under specified conditions or to remove the influence such components.
Furnas Centrais Elétricas S.A is one of the greatest companies of the Brazilian electric power sector and a pioneer in using infrared thermography. In the early 70s, the maintenance policy used was a centralized approach, with only one inspection team to cover all the company’s facilities. In the early 90s, FURNAS decided to decentralize the thermography inspections creating several inspection teams. This new maintenance policy presented several advantages when compared to the previous one. However the credibility of the results obtained with the thermal inspection was frequently being questioned, in part due to the lack of a detailed planning to carry out the transition from the centralized inspection to the decentralized one. In some areas of the company it was suggested the inactivation of the thermography. This paper presents the experience of FURNAS with these different maintenance policies and details the procedures which have been taken that nowadays the infrared thermal inspection has become one of the most important techniques of predictive maintenance in the company.