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  1. 4 Przegląd Elektrotechniczny
  2. 3 Archives of Metallurgy and Materials
  3. 2 Materiały Elektroniczne
  4. 2 Metrology and Measurement Systems
  5. 2 Poznan University of Technology Academic Journals. Electrical Engineering
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  1. 1 2023
  2. 1 2021
  3. 2 2020
  4. 3 2019
  5. 2 2018
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  1. 3 Książkiewicz A.
  2. 2 Boguski J.
  3. 2 Borkowski P.
  4. 2 Frydman K.
  5. 2 Gorczyca K.
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1
Content available Physical and Electrical Properties of Silver-Matrix Composites Reinforced with Various Forms of Refractory Phases
100%
Borkowski P. , Pietrzak K. , Frydman K. , Wójcik-Grzybek D. , Gładki A. , Sienicki A.
Archives of Metallurgy and Materials
|
2018
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tom Vol. 63, iss. 2
817--823
EN
This paper presents technological trials aimed at producing Ag-W, Ag-WC, Ag-W-C and Ag-WC-C composite contact materials and characterizing their properties. These materials were obtained using two methods, i.e. press-sinter-repress (PSR) at the refractory phase content of less than 30% by weight as well as press-sinter-infiltration (PSI) at the refractory phase content of ≥50% by weight). The results of research into both the physical and electrical properties of the outcome composites were shown. They include the analysis of the influence of the refractory phase content (W or WC) on arc erosion and contact resistance changes for the following current range: 6 kAmax in the case of composites with a low refractory phase content, 10 kAmax in the case of composites with the refractory phase content of ≥50% by weight.
2
Content available Effect of Fe Content on the Contact Resistance of Electroplated Au-Fe Alloy Layers
100%
Park H. S. , Son I.
Archives of Metallurgy and Materials
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2018
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tom Vol. 63, iss. 3
1503--1507
EN
In this study, variations in the contact resistance of electroplated Au-Fe alloy layers with Fe content were investigated. The contact resistance of electroplated Au-Fe alloy layers that were subject to thermal aging at 260°C in the atmosphere, tended to increase significantly with an increase in the Fe content. Through an analysis method employing X-ray photoelectron spectroscopy (XPS/ESCA) and Auger electron spectroscopy (AES), Ni oxides, such as NiO and Ni2O3, on the surface of the thermally aged electroplated Au-Fe alloy layers were observed. It is believed that the Ni oxide existing on the surface diffused from the underlying electroplated Ni layers to the surface through the grain boundaries in the electroplated Au-Fe layers during the thermal aging. As the Fe content in the electroplated Au-Fe layers increased, the grain size decreased. As the grain size decreases, more Ni oxide was detected on the surface. Therefore, with a rise in the Fe content, more Ni diffuses to the surface via grain boundaries, and more Ni oxide is formed on the surface of the electroplated Au-Fe layers, increasing the contact resistance of the electroplated Au-Fe alloy layers.
3
Content available Electrical contact temperature change after short-circuit current
100%
Książkiewicz A. , Janiszewski J.
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|
tom No. 78
65--70
EN
Theoretical analysis is preformed concerning temperature rise of electrical contacts exposed to short-circuit current. This temperature is calculated for three different contact materials: AgNi, AgCdO and AgSnO2, used in low voltage electromagnetic relays. An assumption is made that the heat process is adiabatic. Amount of heat is calculated based on let-through energy (Joules heat) of miniature circuit breaker and on real electrical contact resistance. A simplified model of electrical contact heating is proposed.
4
Content available On existence of energy minimizing configurations for mixtures of two imperfectly bonded conductors
100%
Lipton R.
Control and Cybernetics
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1998
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tom Vol. 27, no 2
217-234
EN
We consider a domain filled with a suspension of heat conducting spheres of conductivity sigma[sub p] embedded in a matrix of lesser conductivity sigma[sub m]. It is assumed that there exists a thermal contact resistance at the sphere - matrix interface.The contact resistance is characterized by a scalar Beta, which has dimensions of conductivity per unit lenght. A current flux is prescribed on the domain boundary and we seek the energy minimizing configuration among all suspensions satisfying a reource constraint on the total volume of spheres. We establish the existence of an energy minimizing configuration within the class of polydisperse suspensions of spheres. The optimal suspension depends upon the size of the domain and consists of spheres of radii greater than or equal to R[sub cr] = Beta[...] or no spheres at all. Here R[sub cr] is the ratio between the interfacial resistance and the mismatch between the resistivity of each phase
5
Content available Vacuum switches contact resistance
100%
Janiszewski J. , Książkiewicz A.
Computer Applications in Electrical Engineering
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2014
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tom Vol. 12
227--236
EN
Contact resistance of coupled electrodes, in particular the ones used in high current switches, is a fundamental parameter in determining their rated current (continuous operation) and limit theirs short-circuit current (above which contacts are welded). The paper presents the simulation results of the transition resistance of selected types of contacts calculated with different mathematical models, and assess the extent of their compliance with the results of real objects.
6
Content available Thermal and electrodynamic characteristics of electrical contacts in steady state
100%
Książkiewicz A. , Batura R.
Poznan University of Technology Academic Journals. Electrical Engineering
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2013
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tom No. 74
137--142
EN
In this paper results of theoretical analysis of the thermal and electrodynamic characteristics of electrical contacts are presented. Influences of contact material on temperature changes are discussed. Real contact area impact on electrodynamics of electrical contacts is analysed.
7
Content available remote Łączniki nowe i eksploatowane – porównanie charakterystycznych czasów działania
100%
Pawłot M.
Przegląd Elektrotechniczny
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2014
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tom R. 90, nr 3
203--206
PL
W artykule przedstawiono porównanie charakterystycznych czasów działania łączników elektromagnetycznych fabrycznie nowych i będących w wieloletniej eksploatacji. Analizie poddano takie parametry łączników jak czas załączania wyłączania, niejednoczesność zamykania oraz porównano ilość występujących odskoków przy zamykaniu. W wyniku wieloletniej eksploatacji łączników oprócz zmian ich parametrów cieplnych zmianie ulegają parametry wynikające ze zużycia mechanicznego łącznika w stosunku do fabrycznie nowego.
EN
The article presents a comparative analysis of the operating time parameters concerning brand new swithches and the ones that have been in use for many years. Such parameters as making and breaking times, anticoincidence of the closures, and the number of rebounds at the closing have been analyzed. As compared to brand new switches, switches that have been used for many years, aside with changes in their thermal parameters, exhibit parameter changes resulting from the mechanical wear.
8
Content available Electrical and thermal analysis for the copper removal process in an electric furnace
100%
Zybała R. , Golak S. , Sak T. , Madej P.
Computer Methods in Materials Science
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2023
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tom Vol. 23, No. 4
31--44
EN
The article presents an electrical model of a resistance furnace with two electrodes encompassing the generation of Joule heat. The characteristic feature of this model was the consideration of contact resistance between the electrodes and the slag. A series of analyses were conducted based on this model. Firstly, the impact of contact resistance on current flow and Joule heat generation in the furnace was assessed, demonstrating its significant importance. A separate group of analyses focused on the spatial configuration of the furnace and its interaction with the aforementioned phenomena. The impact of symmetric and asymmetric electrodes immersion was analysed. In addition to the impact on current flow, the study also demonstrated the influence on the natural convection mechanism described by the proposed measures of the spatial non-uniformity of heat generation. The research showed that symmetric electrode immersion allows for the generation of more heat in the system at a constant voltage. Asymmetric electrodes immersion causes an increase in the non-uniformity of heat generation, which translates into a higher intensity of natural convection.
9
Content available Screen printed resistive pressure sensors fabricated from polymer composites with carbon nanotubes
88%
Janczak D. , Wróblewski G. , Jakubowska M. , Słoma M. , Młożniak A.
Challenges of Modern Technology
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2012
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tom Vol. 3, no. 4
14--19
EN
The paper presents the results of the investigation into fl exible layers based on carbon nanotubes used as measuring layer in forcesensor. Results of mechanical fatigue tests show that carbon nanotubes layers are good for reinforcing or as a conductive additive in composite materials. Composition of carbon nanotubes in PMMA polymer resin was prepared by modifi ed mixing process used in thick film material preparation. Sensor structure was fabricated by printing polymer-nanotube areas with polymer-silver paths as connection electrodes on polyester substrate foil. Second type of sensors was prepared with two comb electrodes and single carbon measuring layer. Composite materials were fabricated with diff erent amount of nanotube content: 0,25 wt%, 0,5 wt%, 1 wt% and 2 wt% multiwall carbon naotubes (MWCNT). Diff erent types of carbon-composites measuring layers were compared in the experiment. Results of mechanical fatigue tests conducted on carbon nanotubes layers showed that composition with polymer resin have good adhesion to polymer surface. Experiment shows CNT are good for reinforcing or as a conductive additive in diff erent composite materials. Results of the observations show that dependence between sensor resistance and force tension is linear in logarithmic scale and similar for diff erent samples. Resistance between sensor electrodes was measured for force tension changes in range.
10
Content available remote Coupled mechanical-electrical identification of the contact resistance in the stranded electric power cable
88%
Zeroukhi Y. , Napieralska-Juszczak E. , Komeza K. , Morganti F. , Vega G.
Journal of Achievements in Materials and Manufacturing Engineering
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2012
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tom Vol. 55, nr 2
921--923
EN
Purpose: To analyse the phenomena in the stranded cable it is necessary to know how the contact resistance influenced the current repartition in the cable. The aims of our research are to find the dependence of the cable resistance on the design parameters. Design/methodology/approach: When current passes from one wire to another, the crucial parameter is the resistance of the contact region. The paper presents a method by which this region can be identified and relevant resistance measured. Comprehensive simulations were conducted for different types of wires and cables to assess the influence of design parameters on the current distribution and uniformity. Findings: The found in the course of the work was a method of identification of contact resistance and elaboration of parameters dependence. Research limitations/implications: The future research will be focused on the taking into account the nonhomogenity of the contact area. Practical implications: The presented method will by apply for the optimisation of design of the stranded electric power cable. Originality/value: The novelty is in the way the contact region is identified where current passes from one filament to another. Original relationships have been proposed showing the dependence of the contact region resistance on the design parameters of the cable and mechanical stress.
11
Content available remote Textronic Contact Junction
75%
Zięba J. , Frydrysiak M.
Fibres & Textiles in Eastern Europe
|
2011
|
tom Vol. 19, no. 2 (85)
43-46
EN
An important problem of the textronic application of a textronic contact junction is connecting electronic systems to textile sensors, actuators or power supply systems. This paper presents a special construction of a textronic contac junction. This kind of textronic junction has the form of electroconductive textile velcro. A textile contact junction consists of two electroconductive textile parts: a male and female pin. The construction of an automatic stand for testing the mechanical and electrical properties of textile velcro is also described in this paper. The force, displacement and resistance for different parameters of the connecting process are recorded on the stand. The laboratory stand consists of two compact pneumatic actuators, a force sensor, a displacement sensor, resistance (indirect method) sensors and a PC computer recording system. Some basic research on textile junctions is also presented in this paper.
12
Content available remote Effect of nanocontacts on transient states in electrical circuits
75%
Wawrzyniak M.
Przegląd Elektrotechniczny
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2019
|
tom R. 95, nr 6
110--1116
EN
This paper proposes a model of mechanical switch with stretched nanocontacts based on an analysis of the mechanisms of electron transport within a nanocontact. We use the model proposed to derive equations describing the current in a circuit with an opening switch. The measurement data and the calculation results confirm that nanocontacts substantially modify transient states in the studied circuit and therefore their effect must be taken into account in theoretical analysis.
PL
W artykule na podstawie analizy mechanizmów transportu elektronów w obrębie nanozłączy zaproponowano model łącznika mechanicznego z rozciąganymi nanozłączami. Na podstawie modelu wyprowadzono wzory opisujące prąd płynący w obwodzie elektrycznym podczas otwierania łącznika. Wyniki pomiarów i obliczeń potwierdziły, że nanozłącza w sposób znaczny modyfikują stany nieustalone prądu w badanym obwodzie, co potwierdza konieczność uwzględnienia tego efektu w analizie teoretycznej.
13
Content available remote Erozja łukowa i rezystancja zestykowa silnoprądowych styków z kompozytów WC-Ag
75%
Walczuk E. , Borkowski P. , Kaliszuk K. , Frydman K. , Wójcik-Grzybek D. , Bucholc W.
Materiały Elektroniczne
|
2002
|
tom T. 30, nr 1-2
5-21
PL
Podano wyniki badań erozji łukowej i rezystancji zestykowej kompozytów WC-Ag40 i WC-Ag30 wykonanych metodą nasycania srebrem spieczonego szkieletu z węglika wolframu. Badania zostały wykonane w sterowanym komputerem testującym, przy wysokich prądach, w zakresie od 2 kA do 10 kA. Przeprowadzona dyskusja wyników i porównanie testowanych kompozytów z kompozytami typu wolfram-srebro wykonanymi podobną metodą wykazały, że obecnie testowane kompozyty są bardziej odporne na erozję łukową.
EN
The paper presents results of investigations of arc erosion and contact resistance of the WC-Ag40 and WC-Ag30 composites obtained using the press-sinter-infiltration method. The investigations have been carried out on computer-controlled test system in current range 2-10 kA. Discussion of the results and comparison of the tested materials with the tungsten-silver composites are included.
14
Content available remote Porównanie cieplne łączników elektromagnetycznych nowych i eksploatowanych
75%
Pawłot M.
Przegląd Elektrotechniczny
|
2012
|
tom R. 88, nr 7a
309-311
PL
W artykule przedstawiono porównanie parametrów cieplnych łączników fabrycznie nowych i będących w wieloletniej eksploatacji. Badania dotyczyły pomiarów temperatury zestyku łącznika i spadku napięcia na mostku stykowym. W wyniku badań stwierdzono, że w trakcie eksploatacji zmienia się rezystancja zestykowa oraz warunki oddawania ciepła zdefiniowane kształtem krzywych nagrzewania.
EN
Thermal parameters of new switches and of the ones that have been operated for many years have been compared in the paper. The testing included measurements of temperature at switch contacts and voltage drop at contact junction. The testing has shown that operation processes bring about changes in contact resistance and heat-transfer conditions defined by the shape of heating curves.
15
Wpływ momentu dokręcania na wartość rezystancji połączenia żył przewodów
75%
Skibko Z.
Elektro Info
|
2020
|
tom nr 5
52--53
PL
W artykule przedstawiono podstawy teoretyczne związane z występowaniem rezystancji w układach elektrycznych. Podano również wyniki badań laboratoryjnych pokazujących wpływ momentu dokręcenia śruby w zaciskach śrubowych i główkowych na wartość rezystancji połączenia.
EN
The article presents theoretical fundamentals related to the occurrence of contact resistance in electrical systems. The results of laboratory tests showing the effect of screw tightening torque in screw terminals or screw terminal block on the value of contact resistance are also given.
16
Content available remote Development of the electrical probing methods and criterions for estimation of properties of lubricating materials
75%
Djuzhev A. A. , Korotkevich S. V. , Pinchyk V. G. , Solovej N. F.
Tribologia
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2006
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tom nr 2
61-75
EN
The authors has developed a technique of study the kinetics of forming and boundary lubricant layer damage of the different nature and elaborated the system for the electro-physical sounding on the basis of the CMT-1 testing rig. As a lubricant distilled water, as well as engine and transmission oils were used. The correlation between parameters of electrical conduction, mechanical strength and frictional performances of boundary lubricant layer (GSS) have been established. The analysis of experimental data has allowed to define four modes of boundary friction at the estimation of their antiscuffing properties: (a) the mode of the GSS self-organizing, characterizing by the transition from the physical adsorption to the chemisorption, (b) the mode of the GSS dynamic equilibrium, when processes of the forming and the destruction of the chemisorbed layer are in the dynamic equilibrium, (c) the mode of the chemisorbed layer destruction, and (d) the mode of destruction metallic surface.
PL
Autorzy opracowali technikę badania kinetyki procesu tworzenia i destrukcji granicznej warstwy smarowej różnej natury oraz system pomiarowy do jej realizacji bazując na stanowisku CMT1. Do badań zastosowano destylowaną wodę oraz różne środki smarowe (oleje przekładniowe i silnikowe). Znaleziono korelację pomiędzy parametrami elektrycznymi a mechanicznymi i tarciowymi właściwościami granicznej warstwy smarowej. Analiza danych eksperymentalnych pozwoliła na wyróżnienie czterech procesów tworzenia i destrukcji granicznej warstwy smarowej: a) samoorganizacja warstwy smarowej na drodze przekształcenia warstwy sorpcyjnej z fizycznej na chemiczną, b) stan równowagi pomiędzy tworzeniem i destrukcją warstwy granicznej, c) destrukcja chemisorpcyjnej warstwy, destrukcja powierzchni metalu.
17
Content available remote Investigation of contact resistance influence on power cable joint temperature based on 3-d coupling model
63%
Luo H. , Cheng P. , Liu H. , Kang K. , Yang F. , Yang Q.
Przegląd Elektrotechniczny
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2016
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tom R. 92, nr 5
9--12
EN
Aiming at the overheating problem of cable joint, a 3-D finite element model of a single-core cable joint considering the coupling of electromagnetic field and temperature field has been built. In order to consider the heat losses generated by contact resistance of cable joint, the equivalent conductivity is calculated. The validity of the model and calculation method is verified by the comparison with analytical values.
PL
Do analizy zagadnienia przegrzania połączenia kablowego zbudowano trójwymiarowy model MES przy uwzględnieniu sprzężenia pola elektromagnetycznego i temperaturowego. W celu określenia strat ciepła wytwarzanego w rezystancji styku połączenia kablowego obliczono konduktywność zastępczą.
18
Content available Semiconductor contact layer characterization in a context of hall effect measurements
63%
Kowalewski A. , Wróbel J. , Boguski J. , Gorczyca K. , Martyniuk P.
Metrology and Measurement Systems
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2019
|
tom Vol. 26, nr 1
109--114
EN
A revision of the standard approach to characterization of thin-semiconductor-layer Hall samples has been proposed. Our results show that simple checking of I(V) curve linearity at room temperature might be insufficient for correct determination of bias conditions of a sample before measurements of Hall effect. It is caused by the nonlinear behaviour of electrical contact layers, which should be treated together with the tested layer a priori as a metal-semiconductor-metal (MSM) structure. Our approach was examined with a Be-doped p-type InAs epitaxial layer, with four gold contacts. Despite using full high-quality photolithography a significant asymmetry in maximum differential resistance (Rd) values and positions relative to zero voltage (or current) value was observed for different contacts. This suggests that such characterization should be performed before each high-precision magneto-transport measurement in order to optimize the bias conditions.
19
Content available Application Examples for the Different Measurement Modes of Electrical Properties of the Solar Cells
63%
Musztyfaga-Staszuk M. , Dobrzański L. A. , Rusz S. , Staszuk M.
Archives of Metallurgy and Materials
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2014
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tom Vol. 59, iss. 1
247--252
EN
The aim of the paper was to apply the newly developed instruments ‘Corescan’ and ‘Sherescan’ in order to measure the essential parameters of producing solar cells in comparison with the standard techniques. The standard technique named the Transmission Line Method (TLM) is one way to monitor contacting process to measure contact resistance locally between the substrate and metallization. Nowadays, contact resistance is measured over the whole photovoltaic cell using Corescanner instrument. The Sherescan device in comparison with standard devices gives a possibility to measure the sheet resistance of the emitter of silicon wafers and determine of both P/N recognition and metal resistance. The Screen Printing (SP) method is the most widely used contact formation technique for commercial silicon solar cells. The contact resistance of manufactured front metallization depends of both the paste composition and co-firing conditions. Screen printed front side metallization and next to co-fired in the infrared conveyor furnace was carried out at various temperature from 770°C to 920°C. The silver paste used in the present paper is commercial. The investigations were carried out on monocrystalline silicon wafers. The topography of co-fired in the infrared belt furnace front metallization was investigated using the atomic force microscope and scanning electron microscope (SEM). There were researched also cross sections of front contacts using SEM microscope. Front contacts of the solar cells were formed on non-textured silicon surface with coated antireflection layer. On one hand, based on electrical properties investigations using Sherescan instrument it was obtained the knowledge of the emitter sheet resistance across the surface of a wafer, what is essential in optimizing the emitter diffusion process. On the other hand, it was found using Corescan instrument that the higher temperature apparently results in a strongly decreased contact resistance.
PL
Celem pracy było zastosowanie niedawno opracowanych urządzeń. Corescan” i „Sherescan” do zmierzenia zasadniczych parametrów wytwarzanych ogniw słonecznych w porównani z standardowymi technikami. Standardowa technika nazywana metodą linii transmisyjnych TLM (ang. Transmission Line Method) jest jednym ze sposobów monitorowania procesu pomiaru rezystancji strefy połączenia elektrody z podłożem. Obecnie, rezystancja kontaktu ogniwa słonecznego jest mierzona przy użyciu urządzenia Corescan. Urządzenie Sherescan w porównaniu ze standardowymi urządzeniami daje możliwość pomiaru rezystancji powierzchniowej warstwy dyfuzyjnej emitera płytek krzemowych i rozpoznania typu przewodności P/N i rezystancji kontaktu. Obecnie większość krzemowych ogniw fotowoltaicznych produkowanych na skalę przemysłową wytwarza się z zastosowaniem metody sitodruku do nanoszenia przedniej i tylnej metalizacji. Rezystancja kontaktu wytworzonej przedniej metalizacji zależy zarówno od składu pasty i warunków wypalania. Elektrodę przednią nadrukowano metodą sitodruku, a na- stępnie wypalano w piecu taśmowym w zakresie temperatury od 770°C do 920°C. W niniejszej pracy zastosowano komercyjną pastę srebrną. Badania wykonano na płytkach krzemowych monokrystalicznych. Topografię powierzchni wypalanej w piecu taśmowym przedniej elektrody wykonano stosując mikroskop sił atomowych i skaningowy mikroskop elektronowy. Zbadano również przekroje poprzeczne przednich elektrod stosując skaningowy mikroskop elektronowy. Elektrody przednie ogniw słonecznych wytworzono na powierzchni krzemowej nieteksturowanej z naniesioną warstwą antyrefleksyjną. Na podstawie uzyskanych badań własności elektrycznych za pomocą urządzenia Sherescan stwierdzono, że w zakresie temperatury od 770°C do 920°C, rezystancja właściwa kontaktu mieści się w zakresie 0.43÷1,01 μ Ω/ i rezystancja warstwowa kontaktu mieści się w zakresie 0,28÷0.67 mΩ/ krzemowego ogniwa fotowoltaicznego. W wyniku badań własności elektrycznych wykonanych z wykorzystaniem urządz.enia Corescan uzyskano szczegółową mapę powierzchni oporu styku pomiędzy emiterem a warstwą metalizacji ogniw słonecznych.
20
Content available Semiconductor contact layer characterization in a context of hall effect measurements
63%
Kowalewski A. , Wróbel J. , Boguski J. , Gorczyca K. , Martyniuk P.
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