Thermal Endurance Test Research Articles

Comparative Analysis of Dielectric Behavior under Temperature and UV Radiation Exposure of Insulating Paints for Electrical Equipment Protection—The Necessity of a New Standard?

This paper describes the behavior of some epoxy, acrylic and polyurethane paints used in the protection of electrical equipment under the action of different degradation factors. The degradation factors chosen were temperature and UV radiation. The behavior of the paints under the action of these factors was interpreted by the variation of the tangent of the dielectric loss angle (tg Delta) as well as by FTIR and TG DSC analyses. Tg Delta was considered the reference dielectric characteristic because it best simulates the functionality of the material. The results presented in this paper lead to the conclusion that exposure to thermal cycles and UV radiation is necessary for each paint to give indications about their possibility of use in these conditions. At the same time, the evaluation of thermal stability, even if the exposure is at lower temperatures (than those at which we performed the tests) and/or for shorter periods, is very important for placing the paint in an insulation class. The tests that were the subject of this work provide us with the following information about the three types of paints analyzed: the highest resistance to thermal cycles is presented by S3, followed by S2 and then S1; thermal endurance tests place the polyurethane paint (S3) in insulation class E and the epoxy paint (S1) in insulation class B; and the tests to determine resistance to UV radiation qualify the best paint as acrylic (S2) and the worst as polyurethane (S3). Thus, it can be said that in applications where it is necessary for the protective film to withstand high temperatures, the use of S3 paint (polyurethane) is recommended, and in applications where the films are kept under the influence of UV radiation for a longer time, it is recommended to use coded paint S2 (acrylic). The results presented in this paper lead to the conclusion that the exposure to thermal cycles simulating the use in outdoor conditions and the resilience of paints under UV radiation conditions must be performed for each paint according to its specific use, and the dielectric characteristics must be carefully evaluated because they can reach values under the accepted limit—e.g., thermal stability evaluation—even if the exposure is at lower temperatures and/or for shorter periods. The conclusions of the experimental work must be generalized at different types of electrical insulating paints, and maybe a new standard is necessary to assess the paints’ behavior under usage conditions, with the paints needing to be treated separately from the classical polymeric insulation systems.

Usage of an Excel Spreadsheet for a Thermal Endurance Test Report

Power cables are one of the important parts of electrical power systems. It is important to know the materials that make up the cable or what the life of the cable will be at a given temperature. Therefore, aging tests are performed for the materials used in the cables. One of these tests is the thermal endurance test of the cable. The curve fitting process is performed to the data obtained as a result of this test and the temperature value (the temperature index) corresponding to the 20000-hour life of the cable is found. Automating the process of curve-fitting and finding the temperature index will be useful for companies or research centers that perform this test. Instead of expensive programs such as Matlab or Mathematica, the easy-to-use and accessible Excel program is a very economical and useful solution to evaluate these test results. In this study, the thermal endurance test was briefly described and a spreadsheet was prepared in Excel to evaluate the results of this test. Using the data taken from the measurements made for the EPR material, it has been checked that the spreadsheet works correctly. Such a spreadsheet can be easily used in cable factories to evaluate thermal endurance test results.

Physics of failure and high-temperature reliability on Ag sintered ENIG finished die-attachments at 175 °C for integration of in-wheel motor systems

This study focuses on Ag die bonding failure physics and high-temperature reliability that the die back-side and substrate surface are both finished ENIG when power modules are embedded in-wheel motor systems. The thermal reliability of the Ag sintered die-bonded structures was harsh thermal aging tested for up to 500 h at 250 °C. We systematically investigated the degradation mechanism generated during the thermal endurance test at 250 °C of the die-attach structure bonded with Ag sinter at a very low temperature of 175 °C by EBSD analysis.

Ultra-thin polymer foil cryogenic window for antiproton deceleration and storage.

We present the design and characterization of a cryogenic window based on an ultra-thin aluminized biaxially oriented polyethylene terephthalate foil at T < 10 K, which can withstand a pressure difference larger than 1 bar at a leak rate <1×10-9 mbar l/s. Its thickness of ∼1.7 μm makes it transparent to various types of particles over a broad energy range. To optimize the transfer of 100keV antiprotons through the window, we tested the degrading properties of different aluminum coated polymer foils of thicknesses between 900 and 2160nm, concluding that 1760nm foil decelerates antiprotons to an average energy of 5keV. We have also explicitly studied the permeation as a function of coating thickness and temperature and have performed extensive thermal and mechanical endurance and stress tests. Our final design integrated into the experiment has an effective open surface consisting of seven holes with a diameter of 1mm and will transmit up to 2.5% of the injected 100keV antiproton beam delivered by the Antiproton Decelerator and Extra Low ENergy Antiproton ring facility of CERN.

Orientation-induced properties of anisotropic polyacrylamide thin layer via plasma treatment in liquid crystal system

Uniform liquid crystal (LC) alignment was achieved on a polyacrylamide (PAM) film treated by a plasma ion beam (IB), and the alignment status of the LCs was confirmed by polarized optical microscopy and pretilt angle analysis using antiparallel LC cells assembled using the IB-treated PAM (IB-PAM) layer. Physically modified characteristics on the PAM surface caused by the IB treatment were observed by atomic force microscopy. Etching with the IB caused roughness reduction and smoothing on the surface with increased irradiation time. Chemical modifications on the surface were investigated by X-ray photoelectron spectroscopy, whose results demonstrated stoichiometric changes causing formation of CO bonding and polarity on the surface. The IB incident at 40° drives the surface polarity anisotropy and van der Waals interactions with the LC molecules, thereby achieving uniform LC alignment. Thermal endurance tests of the IB-PAM layer showed maintenance of the uniform LC alignment status up to 120 °C. Twisted-nematic cells based on the IB-PAM layer showed suitable electro-optical performance with low operating characteristics. The IB-PAM films also showed high and stable optical transparencies. Thus, IB treatment on polymer layer is deemed suitable for the LC alignment process, and IB-PAM film is an excellent choice for next-generation LC systems.

Nanopattern transfer on bismuth gallium oxide surface via sol-gel stamp process applied for uniform liquid crystal alignment

A convenient aligning method using nanoimprint lithography is introduced. Sol-gel-processed bismuth gallium oxide (BGO) thin films that are one-dimensionally nanopatterned by polydimethylsiloxane molds are used for the liquid crystal (LC) alignment layer. The one-dimensional nanopatterns are transferred to the films at a curing temperature of 250 °C. Atomic force microscopy data present clear line grooves on the surfaces, which allow the LCs to align parallel to this pattern in one direction. Polarized optical microscopy and pre-tilt angle data support uniformity of the LC alignment, indicating that the surface nanopatterns act as alignment guides for LC molecules. X-ray photoelectron spectroscopy data shows active thermal oxidation at a curing temperature of 250 °C, which contributes to nanopattern transfer on BGO film. Thermal endurance tests of the BGO films show good thermal stability until 180 °C. The twisted nematic cells in the BGO layer also show superior electro-optical performances compared with the conventional rubbed polyimide layer. From these characteristics of the nanopatterned BGO alignment layer and owing to its simple fabrication, we expect that this new alignment technique can be used for producing next-generation LC devices to replace the conventional rubbing process.

DME를 연료로 하는 고압펌프의 성능 및 내열 특성 평가

DME를 연료로 하는 고압펌프의 성능 및 내열 특성 평가

Development of the Particulate Matter Sensor for Diesel Engine

This paper proposes a development of the low-cost and capacitance measurement particulate matter (PM) sensor to monitor diesel particulate filter (DPF) failure. Compared to the resistance measurement PM sensor that is affected by ash accumulated between electrodes due to periodic PM regeneration, capacitance measurement method has the advantage of compensating with capacitance measurement even though the initial ash is present. To reduce the manufacturing cost, we fabricated the proposed sensor with alumina instead of zirconia as the substrate and reduced the sensing area by 26 % compared to the conventional PM sensor. As a result of evaluation, the response time of 5 min required to reach a threshold 50pF at the exhaust gas flow rate of 70 kg/h and PM concentration of 10 mg/m3. It is similar to the conventional PM sensor which takes 343 sec. Durability of the alumina-based PM sensor investigated through thermal endurance test, and the sensor features (C0, R0heater and response time) indicated no significant difference before and after the test.

Polyurethane/clay nanocomposites from palm oil for surface-coating applications

Synthesis of palm oil-based polyurethane (PU) and the formation of nanocomposite from a mixture of PU with clay filler has been performed. Polyol which is the basic material of PU is formed by epoxidation and hydroxylation process and then mixed with isocyanate. Clay used as filler in this study was obtained from the local area of North Aceh, which is a type of swelling of clay that has been modified with cetyltrimethyl ammonium bromide surfactant. Nanocomposites are formed from PU with clay fill variations of 3%, 5%, and 8% by weight of the total mixture of 40 g. The resulting material is tested in character by some type of characterization. Based on the test results with Fourier transform infrared spectroscopy, the hydroxyl polyol group was obtained in groups of 3390.870 (O–H) and –NH as the PU microdomain structure was obtained at a wavelength of 2987 cm−1. Morphological test results using scanning electron microscopy revealed that the addition of modified clay increases the adhesion in the paint and PU coatings and also increases the gloss from the surface and homogeneous material. The thermal endurance test with thermogravimetric analysis reported that the addition of clay fillers in PU showed enhanced effects for better thermal stability in nanocomposite materials when compared with neat polymers. Samples of PU/clay nanocomposites with the addition of 8 wt% clay filler were the most optimum composites among other variations with the thermal degradation temperature value of 296°C. This research generates prospects for applying various industrial surface coatings that are resistant to corrosion and heat, have good mechanical properties, and are more environmentally friendly.

Synthesis and innovation of PLA/clay nanocomposite characterization againts to mechanical and thermal properties

Plastic polymer is one of the most dominant materials of daily human activities because of its multifunctional nature, light and strong and anti-corrosion so it is easy to apply in various equipment. Plastic is generally derived from petroleum material so it is nonbiodegradable. Therefore, this study aims to create a breakthrough of natural and biodegradable biodegradable plastic materials from plant starch (pisok kepok starch) with the help of 3 types of acid (HNO3, HCl and H2SO4) called Poly Lactid Acid (PLA). PLA is enhanced by mixing with a clay material with a variation of 1, 3 and 5% composition to form a PLA / Clay Nanocomposite material which is expected to have superior properties and resemble conventional plastics in general. Several types of characterization were performed to see the quality of the resulting material including tensile strength test with UTM tool, thermal endurance test with TGA tool, morphological structure test using SEM tool and additional test to see filler clay quality through X-RD tool. Based on the characterization of tensile and thermal test, 5B nanocomposite with addition of 5% clay and HCl acid aid showed the best tensile strength of 36 Mpa and the highest stability was 446,63 oC. Based on the results of morphological analysis of the best samples (5B) showed good interface ties. Meanwhile, based on the results of filler analysis, the opening of clay layer d-spacing occurred at 0.355 nm.

Термопрочностные испытания остекления фонаря современного сверхзвукового самолета

Термопрочностные испытания остекления фонаря современного сверхзвукового самолета

Thermal Endurance Testing of Kevlar Fabric/Phenolic Sandwich Composite Protecting the Electronics of a Search and Rescue Robot

Thermal endurance of sandwich panels made of a Kevlar fabric/phenolic composite material has been studied via flame tests. The panels are to be used for the protection of the electronic instruments of robots used for Urban Search and Rescue which are employed under severely adverse operational conditions. As such it is important to determine the time duration that the temperatures will remain at allowable levels inside the robot. These panels are required to be light and have low heat transfer capability. The results show that a combination of composite material design coupled with heat resistant coating provides sufficient insulation to maintain suitable working temperatures for the protected components.

Endurance of Thin Insulation Polyimide Films for High-Temperature Power Module Applications

This paper deals with thermal endurance tests carried out on thin polyimide (PI) films widely used in high-temperature power electronics applications. Specimens deposited on stainless steel supports are aged in an oven in air at four different temperatures up to the glass transition temperature (between 250 $^{\circ}{\rm C}$ and 360 $^{\circ}{\rm C}$ ). Dielectric strength is measured at different aging times as an indicator of PI films endurance. In this paper, in addition to this property, other properties are measured during aging, such as dc conductivity at low field, film thickness, and film morphology. The evolution of these parameters is correlated to the breakdown voltage of the films to establish more accurate endpoint criteria. The results show that the breakdown voltage decreased during aging but not likewise over the whole aging period, because of the effect of the initial surface degradation. This might lead to an underestimation of the lifetime of the films. The thickness degradation rate is constant over the rest of the aging period, making it a suitable endpoint criterion. However, the low field dielectric properties show an improvement during the aging making them an unsuitable aging marker.

International Standard Following to Globalization of Electric Power Technology

Due to the globalization of electric power technology, international standard becomes more and more important because international standard such as IEC standard is typical international standard and recognized as most wide-spread standard. In this paper, recently revised IEC standard 60505 for thermal endurance test method of electrical insulation system is explained as one of the most basic test methods of electrical insulating materials under electrical, thermal, mechanical and environmental stress.

Accuracy and Precision of the Novopen® 3 Insulin Delivery Device after Mechanical and Temperature Stresses

To evaluate the precision, accuracy, and durability of an insulin pen injection device (NovoPen 3) at three preset doses (2 IU, 35 IU, and 70 IU) after exposure to various stress and durability tests that were intended to simulate daily use by patients. Twenty-nine reusable NovoPen 3 insulin delivery devices were tested. The precision and accuracy of 10 insulin pen devices were evaluated after they were subjected to multiple thermal and vibration stress tests. Another 10 pen devices were subjected to a free-fall test. Nine other insulin pens were subjected to endurance testing that simulated 5 years of injections. The accuracy (as measured by the relative error of the delivered dose of insulin) of the insulin pen injection devices was within 1% of the preset dose after all stress or endurance tests. A free-fall test produced no indication of damage except for broken clips and snap catches on the caps, which did not affect the integrity or performance of the insulin pens. The precision of the pen devices (as measured by relative standard deviations of delivered volumes of insulin) was likewise high after thermal stress, vibration stress, free-fall testing, or 5-year endurance testing. Overall, this study showed that the insulin pen injection devices tested were durable under conditions of stress likely to be encountered in daily patient use. Neither a wide variety of repetitive stresses nor insulin injection cycles corresponding to 5 years of use affected the accuracy or precision enough to have clinical significance for reliable insulin delivery.

Evaluation of thermal life for composite dielectrics

The authors describe studies of conventional and rapid thermal endurance test methods for composite insulating materials. A wrapped tube proof voltage (WTPV) approach was selected as the diagnostic property for the conventional ageing (CA) procedure.

チタン・アルミ・タービン・ホイールの実用化

Present paper reported the first commercial application of titanium-aluminide (TiAl) in the world. TiAl is one of the heat-resistant light materials, which has low density and high specific strength at elevated temperatures. TiAl was applied to turbine wheel of turbocharger of commercial sport type vehicles. Mitsubishi Heavy Industries newly developed high performance turbocharger with TiAl turbine wheel which was produced by special precision casting process for reactive metals called LEVI-CAST. Weight reduction of the turbine wheel due to adaptation of TiAl improved transient response of turbocharger. The turbocharger passed continuous and thermal cyclic endurance test. Mitsubishi Motors Corporation adopted it for gasoline engine of Lancer Evolution VI(RS).

Comparison of reliability of conventional and rapid aging methods for insulating materials

It is shown that the conventional aging (CA) method of insulating materials is only an approximation, and simulates the actual service of insulation. Since the test is complex and uncertain, CA cannot be absolute. Although most rapid thermal endurance test methods of insulating materials are based on CA, once established, they are independent test methods. Further, the dispersion of CA data is large and repeating the tests is difficult due to its long time and high costs. Rapid methods, such as thermogravimetric point slope (TPS), have smaller scatter, higher success ratio, and good accuracy and are easy to repeat. Therefore, taken as a whole, the reliability of TPS may well be identical with, or even better than, that of CA for determining the thermal endurance properties of insulating materials. >

A Short-Time Thermal Endurance Test Method of Polymeric Electrical Insulating Materials by Evolved Gas Analysis

A Short-Time Thermal Endurance Test Method of Polymeric Electrical Insulating Materials by Evolved Gas Analysis

Thermal degradation of electrical insulating materials and the thermokinetic background: experimental data

For pt.I see ibid., vol.25, 1029-1036, 1990. The purpose of this work is to verify the validity of the new degradation model and the transformation equations which have been developed on the basis of thermokinetic considerations. This verification is implemented by comparing the temperature index (TI) values obtained by the thermal life equations, and their converted forms as transformation equations, for a large amount of material data with TI results estimated by tests carried out according to IEC Standard 216. The TI values relate to insulating materials with constant endurance-line slope as well as to materials with both constant and variable endurance-line slope. These families of life lines are named either parallel or nonparallel life lines. The equations developed provide estimates of the TIs that are, in general, close to those obtained by thermal endurance tests conducted according to IEC 216 procedures.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>