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Tytuł:
Field-circuit analysis of AC machine taking into account stator winding asymmetry
Autorzy:
Pietrowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1813709.pdf
Data publikacji:
2012
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
winding asymmetry
induction machine
axial flux
field-circuit model
Opis:
The paper presents the influence of an asymmetry of a stator winding on an axial flux in AC machine. The objective research was performed for selected values of asymmetry. The axial flux was calculated as the sum of flux linkage with stator winding. In order to achieve a magnetic field distribution a dedicated 2D finite element model of AC machine was elaborated. The waveforms of axial flux and torque-time characteristic have been shown. It can be concluded that the asymmetry has significant impact on the axial flux and the pulsation of torque.
Źródło:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały; 2012, 66, 32; 386-392
1733-0718
Pojawia się w:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transitional processes at capacitive currents switching-off by single and double-break interrupters of vacuum circuit breakers
Autorzy:
Lazimov, T.
Saafan, E.
Powiązania:
https://bibliotekanauki.pl/articles/410591.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vacuum circuit breaker
double-break vacuum interrupters
SF6 circuit breaker
capacitor banks
transient recovery voltage
dielectric strength
breaking capacity
Opis:
Vacuum circuit breaker technology based on double-break vacuum interrupters has become the most requirements of high voltage circuit breakers that not environmentally harmful. The vacuum interrupter has an excellent ability to deal with the steep rising part of the transient recovery voltage, which makes it faster in the current interruption process. This paper presents results of computer simulations conditioned by capacitive currents switching-offs by using single and double interrupters of vacuum circuit breakers. These results demonstrate that use of double-break circuit breakers leads to notable decreasing of switching overvoltages and allows in the same time to meet the dielectric requirements for high voltage vacuum circuit breakers.
Źródło:
Present Problems of Power System Control; 2014, 5; 33-43
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stator winding inter-turn short-circuit modelling of a squirrel-cage induction motor
Autorzy:
Radecki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1193158.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
squirrel-cage induction motor modelling
induction motor faults
stator winding inter turn short-circuit
Opis:
A mathematical model of a squirrel-cage induction motor with inter-turn short-circuits in stator phases is presented in this paper. In the proposed mathematical model an extent and angular localization of short-circuit faults are determined using a simple form of short-circuit coefficient matrices. The model does not require any additional motor parameters than those that are required for conventional model of healthy induction motor. Comparative results obtained through computer simulations and from a laboratory test-stand with 2.2 kW induction motor are contained in the article. The results obtained validate the proposed extended mathematical model of a squirrel-cage induction motor with inter-turn short-circuit of stator windings.
Źródło:
Power Electronics and Drives; 2016, 1, 36/1; 139-148
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transitional processes at switching-off unloaded power transmission lines by modern circuit-breakers and their computer simulation
Autorzy:
Lazimov, T.
Saafan, E.
Powiązania:
https://bibliotekanauki.pl/articles/410587.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
SF6 circuit-breakers
power transmission lines
computer simulation
transitional voltages
Opis:
The article presents results of transitional processes computer simulation at switching-off unloaded power transmission line of rated voltage 220 kV by auto-compression (SF6) circuit-breakers. Transitional voltages (voltage across the line terminals and recovery voltage) at switching-off were calculated and studied in the research carried out. There was also considered dependence between transitional voltages magnitudes and power transmission lines lengths. There were studied some computational peculiarities of the problem under consideration. In particular, the numbers of pi-sections provided satisfactory adequacy of lines equivalency at computer simulation for their typical lengths were determined. There were also estimated optimum simulation parameters provided stability of transitional regime parameters.
Źródło:
Present Problems of Power System Control; 2013, 4; 67-75
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the efficiency of metal recovery from printed circuit boards using gravity processes
Autorzy:
Franke, Dawid M.
Suponik, Tomasz
Nuckowski, Paweł M.
Dubaj, Justyna
Powiązania:
https://bibliotekanauki.pl/articles/1445935.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
metals recovery
printed circuit board
gravity separation
ICP-AES
SEM-EDS
Opis:
This paper evaluates the efficiency of metal recovery from printed circuit boards (PCBs) using two gravity separation devices: a shaking table and a cyclofluid separator. The test results were compared with the results obtained from previous research, where an electrostatic separation process was used for an identically prepared feed. The feed for the separators consisted of PCBs shredded in a knife mill at cryogenic temperatures. The separation efficiency and purity of the products were evaluated based on microscopic analysis, ICP-AES, SEM-EDS, XRD, and specific density. The yield of concentrates (valuable metals) obtained from the shaking table and the cyclofluid separator amounted to 25.7% and 18.9%, respectively. However, the concentrate obtained from the cyclofluid separator was characterised by much higher purity, amounting to ~88% of valuable metals, compared to ~72% for the shaking table. In both cases, middlings formed a significant share, their yield amounting to ~25%, with the share of valuable metals of ~15%. The yield of waste obtained from the shaking table and the cyclofluid separator were 42.6% and 52.5%, respectively. In both cases, as a result of the applied process, the waste was divided into two homogeneous groups differing in grain size and shape. The recovery of metals through gravity separation is possible, in particular, by using a shaking table. These processes can also be applied to separate waste (plastics) into two groups to be selectively processed to produce new materials in line with a circular economy.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 4; 63-77
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Copper recovery from waste printed circuit boards and the correlation of Cu, Pb, Zn by ionic liquid
Autorzy:
Li, F.
Chen, M.
Powiązania:
https://bibliotekanauki.pl/articles/208289.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electronic waste
printed circuit boards
heavy metals
waste disposal
metale ciężkie
odpady elektroniczne
odpad płytek drukowanych
miedź
Opis:
Waste printed circuit boards (WPCBs) contain not only harmful materials but also many valuable resources, especially metals, which attracts more and more attention from the public. In this study, a sulfonic acid functionalized ionic liquid ([BSO3HPy]OTf) was used to recycle copper from WPCBs. Zinc and lead, represented as typical heavy metals, were chosen to study the leaching behavior and their relation to copper. Five factors such as particle size, ionic liquid (IL) concentration, H2O dose, solid to IL ratio and temperature were investigated in detail. The results showed that copper leaching rate was high, up to 99.77%, and zinc leaching rate reached the highest value of 74.88% under the optimum conditions. Lead cannot be leached effectively and the leaching rate was mostly low than 10%, which indirectly indicated that [BSO3HPy]OTf has a good selectivity to lead. Besides, the interaction of copper, lead and zinc was characterized macroscopically by means of statistical methods. The Spearman correlation analysis showed that copper and zinc had a highly positive correlation. Lead had little relation to copper, which to some extent indicated that the effect of zinc on copper leaching behavior was bigger than that of lead.
Źródło:
Environment Protection Engineering; 2017, 43, 4; 55-66
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On interaction between circuit-breaker and network at small inductive currents switching-offs
O wzajemnym oddziaływaniu wyłącznika i sieci podczas wyłączeń małych prądów indukcyjnych
Autorzy:
Lazimov, T.
Saafan, E.
Powiązania:
https://bibliotekanauki.pl/articles/410577.pdf
Data publikacji:
2011
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
SF6 and vacuum circuit-breakers
dielectric strength restoration
small inductive currents
overvoltage
recovery voltage
Opis:
Results of an investigation of interaction between circuit-breaker against its dielectric strength restoration law and parameters such as chop current and operation time (all conditioned by the circuit-breaker type and arc quenching medium) at small inductive currents' switch-offs are presented in this article. The results include curves of transitional voltages at switching under consideration and also conclusions on dependence of overvoltages and recovery voltages ratios on re-ignitions in inter-contact space. The results concerning investigation of stability are also presented. The analyzed methods were investigated from the point of view of stability in wide range of simulation parameters.
W artykule przedstawiono rezultaty badania wzajemnego powiązania rodzaju wyłącznika oraz prawa odbudowy wytrzymałości dielektrycznej i jego parametrów determinowanych rodzajem wyłącznika oraz zastosowanym medium gaszenia łuku), takich jak prąd ucięcia oraz czas wyłączenia podczas wyłączania małych prądów indukcyjnych. Badania dotyczyły określania napięć przejściowych podczas rozważnych operacji łączeniowych oraz zależności przepięć i napięć powrotu na ponowne zapłony w przestrzeni między biegunami wyłącznika. Przedstawiono również rezultaty badań stabilności obliczeń, przeprowadzonych w szerokim zakresie parametrów symulacji.
Źródło:
Present Problems of Power System Control; 2011, 1; 29-37
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical separation route for printed circuit boards
Autorzy:
Burat, F.
Özer, M.
Powiązania:
https://bibliotekanauki.pl/articles/109975.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
physical methods
PCBs
environment
copper
gold
silver
Opis:
Recently, the consumption of electrical and electronic equipment (EEE) has increased with the advanced technology. A wide range of components made of metals, plastics and other substances are contained in EEE. Electronic waste (e-waste) is easily demounted and separated by manually methods; however, printed circuit board (PCB) which is one the most common components of e-waste need to be recycled with economic and environmental technologies. In this paper, employing physical separation methods to ground waste PCB, an eco-friendly, simple and environmental process for separation of valuable metals was designed and proposed. A heavy fraction with 40.8% Cu, 350 ppm Au and 475 ppm Ag content at recovery of 95.4% Cu, 77.7% Au and 65.1% Ag was obtained from a feed assaying 12% Cu, 130 ppm Au and 200 ppm Ag using shaking table separator. Cu grade was increased from 52.4% to 73.9% with the recovery over 92% by dry magnetic separator and copper alloys were separated from the waste matrix with 98% Cu recovery using electrostatic separator.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 554-566
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of ferroresonance oscillations in capacitive voltage transformer
Autorzy:
Iżykowski, J.
Rosołowski, E.
Pierz, P.
Powiązania:
https://bibliotekanauki.pl/articles/410537.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
capacitive voltage transformer
ferroresonance
suppression circuit
chaotic behaviour
simulation
Opis:
Analysis of ferroresonance oscillations in capacitive voltage transformer is presented. For this purpose an analytical approach to ferroresonance is firstly introduced. With use of the harmonic balance method the condition for avoiding stable subharmonic oscillations of the 3rd mode is stated. In the next step the ATP-EMTP simulation based investigations are carried out to find the suppression circuit parameter (or parameters) which assure damping of the nonlinear oscillations in accordance to the requirements of the standards. Two kinds of suppression circuits designed for the considered capacitive voltage transformer construction are investigated. The possible chaotic phenomena resulting from nonlinear oscillations are also examined. The obtained results are pr esented and discussed.
Źródło:
Present Problems of Power System Control; 2015, 6; 43-66
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of effective parameters for molybdenite recovery from porphyry copper ores in industrial flotation circuit
Autorzy:
Nakhaei, F.
Irannajad, M.
Powiązania:
https://bibliotekanauki.pl/articles/110240.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation
copper
molybdenum
recovery
Opis:
The Sarcheshmeh copper mine is a significant copper and molybdenum producer. Sampling of the Sarcheshmeh flotation circuit (in a six-month period) showed that a large share of waste of molybdenite took place in rougher cells. Since the rougher cells tailing is transferred to tailing thickener, the main focus of this paper was on this section. In the current study, the factors which influence the recovery of molybdenite and copper were investigated. Molybdenite recovery in the bulk flotation circuit was consistently lower than that of the copper sulphides as well as being far more variable. This paper describes the methodically use of size by size recovery data, quantitative mineralogy, and liberation degree analysis to identify the factors contributing to molybdenite recovery relative to copper in industrial rougher circuit. The results showed that the size by size recovery for both metals in the ultrafine and coarse fractions recovery was reduced. On the other hand, the highest recovery occurred in the intermediate sizes from 27 μm to 55 μm. Molybdenum recovery in the fine and ultrafine and coarse fractions drops off to a greater extent than the recovery of copper. The investigations of degree liberation showed that the recovery of copper sulphides is more dependent on the liberation state of valuable minerals while for molybdenite some other factor splay a significant role.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 477-491
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recycling of non-metallic powder from printed circuit board waste as a filler material in a fiber reinforced polymer
Autorzy:
Kanchanapiya, P.
Pinyo, W.
Jareemit, S.
Kwonpongsagoon, S.
Powiązania:
https://bibliotekanauki.pl/articles/207195.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electronic waste
printed circuit boards
recycling
nonmetallic powder
filler material
fiber reinforced polymer
odpady elektroniczne
odpad płytek drukowanych
wykorzystanie odpadów
proszek niemetaliczny
recykling
materiał wypełniający
polimer wzmocniony włóknami
Opis:
Rapid growth in the electricity and electronics industry in Thailand has resulted in numerous problems with electrical waste management. Printed circuit board (PCB) components contain copper in an amount of approximately 10 wt. % and approximately 90 wt. % of non-conductive substrate made from fiberglass resin. In the recycling process, after copper is physically separated from PCB, only nonmetallic powder (NMP) will be left; that needs to be properly disposed of and managed. Therefore, this study is a proposal of suitable choices for NMP management. The results showed that NMP can be disposed in hazardous waste landfill. Furthermore, NMP can be recycled as a component in fiber- -reinforced polymer (FRP) of the following composition: coarse NMP 25%, fine NMP 25%, polyester 38.8%, hardener (Butanox type) 0.6%, catalyst (cobalt type) 0.6%, styrene monomer 10%. This FRP mixed with NMP can be properly processed into an artificial wall tile product in terms of mechanical properties, manufacturing processes and conditions of use.
Źródło:
Environment Protection Engineering; 2015, 41, 4; 151-166
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on composite manufacturing method of semi-buried 1×32 optical splitter
Autorzy:
Tao, Qing
Xie, Sihao
Powiązania:
https://bibliotekanauki.pl/articles/27310089.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical splitter
composite manufacturing method
EOPCB
electro-optical printed circuit board
Opis:
In this paper, a composite manufacturing method was proposed to reduce the inner surface roughness of silica groove. Firstly, femtosecond laser was used to ablate the silica groove, then, a 5% concentration hydrofluoric acid solution was used to corrode the inner surface of silica groove. Secondly, Su8 adhesive was filled with the groove to form a semi-buried 1×32 optical splitter by doctor blade. The test results showed that the surface roughness Ra was less than 0.2 μm, and average insertion loss of output ports was 21.34 dB, moreover, the uniformity was less than 1.44 dB. Compared with the traditional femtosecond laser ablating method, surface roughness reduced by at least 0.1 μm, and the average insertion loss of output ports was reduced by 1.22 dB, and the uniformity was reduced by 0.41 dB. So, the composite manufacturing method improved the communication performance. It is satisfied with the requirements for optical interconnection in the electro-optical printed circuit boards.
Źródło:
Optica Applicata; 2023, 53, 2; 185--197
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnostic system for induction motor stator winding faults based on axial flux
Autorzy:
Wolkiewicz, M.
Skowron, M.
Powiązania:
https://bibliotekanauki.pl/articles/1193462.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
stator winding fault
inter-turn short circuit
axial flux
diagnostic system
Opis:
The article presents the results of research on the use of an axial flux in the diagnostics of induction motor stator winding fed by a frequency converter. Voltage signal waveforms proportional to the axial flux were recorded during motor operation under various conditions and were analyzed with regard to the detection of stator winding short circuits. The taps of the selected coil turns of stator phases were introduced into the tested motor, which allowed to physical modelling inter-turn short circuits. The structure and operation of the computer system used to monitor the state of induction motor windings were discussed. The developed diagnostic system was made in the National Instruments LabVIEW environment. The analysis of faults of the axial flux was made in the detection of induction motor stator winding. The results of experimental research conducted using the developed diagnostic system have also been presented.
Źródło:
Power Electronics and Drives; 2017, 2, 37/2; 137-150
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent sustainable trends for e-waste bioleaching
Autorzy:
Al Sultan, Mohammed Sami
Benli, Birgül
Powiązania:
https://bibliotekanauki.pl/articles/24085614.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bioleaching
e-waste
sustainable mining
used electronic components
waste printed circuit boards
recovery metal
Opis:
For the past few decades, the electronic and electrical waste have been accumulating and piling on our lands and aside from posing some serious threat on our environment and our health. And with the technological advance and the rapid growing electronic demand and production there is the risk of accumulating even more unused valuable usable materials in our waste land-fields. Up to 2030, EU is forecasting about 74 million tons of e-waste, including washing machines, tablet computers, toasters, and cell phones. In 2022, more than 5.3 billion mobile phones were wasted whereas Li, Mn, Cu, Ni, and various rare-earth elements (like Nd, Eu and Tb, etc.) as well as graphite are actually found in the contents of many metal parts from wiring, batteries to their components. The main purpose aside from an environmental aspect is reserving the mineral used in this waste, as many of the crucial materials have a supply risk heavily depending on import. For instance, many of these rare earth elements (REE) are sourced from China; these REEs are used in many electronics that range from consumer products to industrial-use machines. This study is to review one of the desired methods that is via using bio-techniques to dissolve and recover as much as possible from main e-waste sources such as PCBs, spend batteries and LCD/LED panels. Microorganisms that are used for bioleaching process and their metal recovery aspects were compared in the second part. Future perspectives were finally added considering significant techno-economic environmental and social impacts.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 5; art. no. 167375
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selection of the best route for column configuration in an existing copper circuit
Autorzy:
Can, N. Metin
Altun, Okan
Powiązania:
https://bibliotekanauki.pl/articles/109679.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
column flotation
sulphide ores
distribution of wash water
airflow rate
froth height
Opis:
This study was aimed to utilize column flotation to obtain much cleaner concentrate in the Cu circuit. However, the numbers of equipment and the proper streams for column application should be the key for successful operation. Therefore, the effects of some operational parameters such as wash water rate, airflow rate and froth height were investigated on the streams of namely Cu first cleaner concentrate, Cu rougher concentrate and Cu third cleaner concentrate in terms of mineral recoveries and selectivity. Distribution of wash water rate to products was also determined by a tracer test method. Optimum operating conditions and accordingly performance of the column were determined by simulation studies. According to the results, the suitable streams for industrial scale flotation column are advised as the rougher concentrate and/or first cleaner concentrate. With series installation of columns, it is possible to obtain two different concentrates which include 22% Cu, 4% Zn and 17% Cu, 8% Zn without any decrease in overall recovery of plant.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 2; 552-564
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
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