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Wyszukujesz frazę "insulation" wg kryterium: Temat


Tytuł:
An analysis of the influence of microclimate on partial discharge activity in emissions of electric machines in the conditions of industrial operation – own research
Autorzy:
Plutecki, Z.
Szymaniec, S.
Powiązania:
https://bibliotekanauki.pl/articles/141042.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
HV electrical machines
partial discharge in winding insulation
on-line insulation diagnosis
microclimate
Opis:
The article presents the results of diagnostic measurements of partial discharge signal propagation from the winding insulation in electrical machinery, which were performed using an on-line method. This paper describes the results of experiments and the acquired experience in the monitoring of winding insulation in high power and high voltage electrical machines which are important in industrial production processes. The authors show the measurement techniques employed in their research. Representative measurement results are presented along with their analysis. The authors use an SKF monitoring systems to measure: vibrations, temperature, and humidity, as major factors affecting partial discharge activity in the from winding insulation of electrical machines.
Źródło:
Archives of Electrical Engineering; 2013, 62, 4; 629-648
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Streaming electrification of insulating liquid mixtures
Autorzy:
Zdanowski, Maciej
Maleska, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/141677.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dielectric liquids
streaming electrification
transformer insulation
Opis:
Extensive efforts have been made for many years by the power generating industry to replace conventional solid and liquid insulation with synthetic materials. Those measures are aimed at increasing the load capacity, improved fire safety and extending transformer life during exploitation. Modern insulating materials include aramid fibre-based paper and insulating fluids made of synthetic and natural esters. The paper presents research results of the electrostatic charging tendency (ECT) of mixtures of fresh and aged mineral oil Trafo En with synthetic ester Midel 7131 and natural ester Midel 1204. The measurements were taken in a flow-through system using the pipes made of metal, cellulose and aramid paper. The influence of the liquid flow velocity, the type of material of the measuring pipe and the mixture content on the level of the streaming electrification current generation was determined.
Źródło:
Archives of Electrical Engineering; 2019, 68, 2; 387-397
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Materials Resistant to High Temperatures Obtained from Post-Production Fibrous Waste
Autorzy:
Kogut, K.
Kasprzyk, K.
Kłoś, R.
Powiązania:
https://bibliotekanauki.pl/articles/355061.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
waste
thermal insulation
ceramic
porosity
fibers
Opis:
This paper describes preparation methodology and research results of newly developed materials from post-production fibrous waste that are resistant to high temperatures. Widely available raw materials were used for this purpose. Such approach has significant impact on the technological feasibility and preparation costs. Obtained materials were verified via applying of various tests including characterization of shrinkage, porosity, density and water absorption as well as X-ray analysis (XRD), followed by mechanical bending and compressive strength determination. Based on the research results, the possible applications of materials as thermal insulators were indicated.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 2; 845-850
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the Possibility of Limiting the Impact of Ground Vibrations Caused During Demolition of a Towers on Environment
Autorzy:
Targosz, J.
Bednarz, J.
Lisowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/177131.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ground vibrations
insulation layers
vibrations measurements
Opis:
Before disassemble and demolition of five granulation towers the authors planned and carried out measurements of the intensity of vibrations induced during the fall of the dismantled components of towers on the ground. The main aim of the study was to determine the maximum permissible weight of falling elements of the towers during the demolition, in terms of ensuring the protection of buildings and equipment located in the vicinity of the works. It was unacceptable to increase the vibration amplitudę displacement in each section of measurement on each of the three perpendicular axes by more than 2 µm peak-to-peak value and the absolute velocity of RMS of vibration amplitude couldn’t be increased by more than 1 mm/sec value than the background vibration during the demolition of the towers. Preliminary experimental studies were conducted on a test stand and the measurements were made on the real object. The amplitudes of vibration waves displacement and velocity were recorded on the measurement section in the direction of the protected building. The results of measurements were used to identify the propagation of the shock wave and the effectiveness of the proposed insulation layers.
Źródło:
Archives of Acoustics; 2016, 41, 4; 649-657
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling and Experimental Verification of Ultrasound Transmission in Electro Insulation Oil
Autorzy:
Wotzka, D.
Cichoń, A.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/177158.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasound transmission
numerical simulations
electro-insulation oil
Opis:
A verification study of ultrasound transmission numerical simulation results with experiment results is presented in this paper. The work considers a model of a transformer tank which is filled with electro insulating oil. In the experiment, performed under laboratory conditions, an ultrasound wave is generated by a piezoelectric transducer that is fixed in the centre of the tank and measured by another transducer mounted inside the tank at three distances: 10, 20 and 30 cm from the sound source. The transducer is able to measure and generate acoustic waves in the ultrasound frequency band up to 1 MHz. The simulation considers numerical calculation of acoustic pressure distribution inside the tank in which acoustic source emits waves with frequency equal to 100 kHz. Verification analysis has confirmed consistency of the numerically calculated values with the measurement results.
Źródło:
Archives of Acoustics; 2012, 37, 1; 19-22
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monitoring of Partial Discharges in Cable Insulation and Cable Head Using Acoustic Method
Autorzy:
Ranachowski, Zbigniew
Wieczorek, Krzysztof
Ranachowski, Przemysław
Dębowski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2141672.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
partial discharges
medium voltage insulation
acoustic emission
Opis:
The article presents the application of Acoustic Emission (AE) method for detection and registration of partial discharges (PD) generated in medium voltage (MV) cable isolation and MV cable head. The insulation of the high voltage cable is made of a flexible material whose properties are characterised by a high coefficient of attenuation of the acoustic signals. For this reason, the AE method has not been used so far to detect PD in energetic cables. The subjects of the research were the MV cable and the standard T-type cable head. The cable contained defects which were the source of partial discharges. In case of cable head the PD were provoked by thin grounded electrode which was introduced into connector opening. The results of AE measurements are presented in the form of spectrograms. Acoustic Emission was evoked when the applied voltage level reached the value of 7.5 kV for the cable and 4 kV for the cable head. The authors used the acoustic instrumentation of their own design intended for future field use. Obtaining successful results of partial discharges measurements using the acoustic method in the cable insulation makes an original contribution of the presented work.
Źródło:
Archives of Acoustics; 2022, 47, 2; 259-265
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Insulation and Mechanical Properties in the Presence of Glas Bubble in Fly Ash Geopolymer Paste
Autorzy:
Shahedan, Noor Fifinatasha
Abdullah, Mohd Mustafa Al Bakri
Mahmed, Norsuria
Liew, Yun Ming
Shayfull, Zamree Abd Rahim
Aziz, Ikmal Hakem A.
Kadir, Aeslina Abdul
Sandu, Andrei Victor
Ghazali, Mohd Fathullah
Powiązania:
https://bibliotekanauki.pl/articles/2048833.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
glass bubble
thermal insulation
geopolymers
fly ash
Opis:
The density, compressive strength, and thermal insulation properties of fly ash geopolymer paste are reported. Novel insulation material of glass bubble was used as a replacement of fly ash binder to significantly enhance the mechanical and thermal properties compared to the geopolymer paste. The results showed that the density and compressive strength of 50% glass bubble was 1.45 g/cm3 and 42.5 MPa, respectively, meeting the standard requirement for structural concrete. Meanwhile, the compatibility of 50% glass bubbles tested showed that the thermal conductivity (0.898 W/mK), specific heat (2.141 MJ/m3 K), and thermal diffusivity (0.572 mm2 /s) in meeting the same requirement. The improvement of thermal insulation properties revealed the potential use of glass bubbles as an insulation material in construction material.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 1; 221-226
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biographical sketch of Jerzy Ignacy Skowroński
Autorzy:
Chrzan, Krystian Leonard
Powiązania:
https://bibliotekanauki.pl/articles/2008103.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Jerzy Ignacy Skowroński
electrical engineering
high voltage insulation
Opis:
The life of Jerzy Ignacy Skowronski, Professor of High Voltages, Dean of the Faculty of Mechanical and Electrical Engineering and the first Dean of the Electrical Faculty of the Wrocław University of Science and Technology, member of the real Polish Academy of Sciences and President of the Wrocław Scientific Society, founder of the Wrocław Scientific School of Electrical Materials, was described. Documents contained in the Archives of the Wrocław University of Science and Technology, works published by Jerzy I. Skowronski, previously published publications on his scientific merits written by his former Ph.D. students and information from his grandson Jan Paweł Skowronski were used. The author's intention was to show unknown facts from the life of the Professor and his works unknown until now.
Źródło:
Nauka; 2021, 1; 149-157
1231-8515
Pojawia się w:
Nauka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of a Phase Resolved Partial Discharge Pattern Analysis for Acoustic Emission Method in High Voltage Insulation Systems Diagnostics
Autorzy:
Kunicki, M.
Cichoń, A.
Powiązania:
https://bibliotekanauki.pl/articles/177912.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic emission
partial discharge
transformer diagnostics
insulation system
Opis:
An alternative method for analysis of acoustic emission (AE) signals generated by partial discharges (PD), based on a correlation between voltage phase run and AE pulses, so called phase resolved PD pattern (PRPD), is presented in the paper. PRPD pattern is a well-known analysis tool commonly used in such PD diagnostic methods as conventional electrical and UHF ones. Moreover, it yields various signal analysis abilities and allows a direct correlation indication between measurement results achieved using different methods. An original PRPD measurement methodology applied for AE method as well as some exemplary measurement results and further data analysis capabilities are presented in the paper. Also a comparative analysis of PRPD patterns achieved using various measurement methods and different PD source configurations have been investigated. All presented experiments were done under laboratory conditions using PD model sources immersed in the insulation oil. The main purpose of the presented research is to indicate an all-embracing analytical tool that yields an ability to direct comparison (qualitative as well as quantitative) of the AE measurement results with other commonly applied PD measurement methods. The presented results give a solid fundamental for further research work concerning a direct correlation method for AE and other described in the paper diagnostic techniques, mainly in order to continue PD phenomena analysis and assessment in real life high voltage apparatus insulation systems under normal onsite operation conditions.
Źródło:
Archives of Acoustics; 2018, 43, 2; 235-243
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low voltage winding insulation systems under the influence of high du/dt slew rate inverter voltage
Autorzy:
Pauli, Florian
Ruf, Andreas
Hameyer, Kay
Powiązania:
https://bibliotekanauki.pl/articles/140993.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
life time
partial discharge
SiC semiconductors
winding insulation system
Opis:
Variable speed and low voltage electrical drives are commonly operated by frequency converters. According to recent developments, there is a trend in the area of semi-conductors, that switching frequency and voltage slew rate will increase significantly. The aim of these semiconductors is to reduce the switching losses and to increase the switching frequency, which enables to reduce the size of passive components in the powerelectric circuit. This results in less material effort and lower cost, for the power electronic component. However, electric motors operated by high slew rate inverters show problems in the winding insulation, which have to be analyzed. Such problems are well known for high voltage machines. Due to the increasing slew rate, this problematic occurs in low voltage machines nowadays as well. Here, the influence of fast switching semiconductors on the winding insulation system is studied, using accelerated ageing tests with fast switching high-voltage generators.
Źródło:
Archives of Electrical Engineering; 2020, 69, 1; 187-202
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variable Sound Insulation Structure with MFC Elements
Autorzy:
Górski, P.
Kozupa, M.
Powiązania:
https://bibliotekanauki.pl/articles/177289.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound insulation
active noise reduction
macro fiber composite (MFC)
Opis:
Additional sound sources are used as actuators in the vast majority of active noise reduction systems. One of the possible opportunities to extend the field of applications of active noise reduction systems is using active structures of variable sound insulation. The paper presents an analysis of ways of reducing noise with a structure of variable sound insulation consisting of a metal plate, active elements (Macro Fiber Composite), and a control system. The paper presents results of acoustic radiation simulations and measurements of sound intensity generated by the structure under the influence of stimulation by an acoustic wave. Simulations of mechanical vibrations and acoustic radiation for the plate were performed with the finite element method and ANSYS software. Simulation results made it possible to select locations for gluing the active elements and sensors. Analyses of the sound pressure level in the space to which the plate is radiating made it possible to determine dominant frequencies in the characteristics and, as a result, indicate vibration modes that can be reduced. Sound intensity measurements were performed with a three-way probe of USP mini Microflown. Results of simulations and measurements show that it is possible to achieve an improvement of the insulating power of a metal plate by approx. 10 dB.
Źródło:
Archives of Acoustics; 2012, 37, 1; 115-120
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variability of the predicted insulation index of clothing in the Norwegian Arctic for the period 1971-2000
Autorzy:
Araźny, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2051892.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Norwegian Arctic
bioclimate
predicted insulation of clothing
atmospheric circulation
Źródło:
Polish Polar Research; 2006, 27, 4; 341-357
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of concentrated winding topologies considering transient voltages in the winding system of inverter-driven low-voltage machines
Autorzy:
Pauli, Florian
Driendl, Niklas
Mönninghoff, Sebastian
Hameyer, Kay
Powiązania:
https://bibliotekanauki.pl/articles/2172796.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
d/d
electrical machines
insulation system
inverters
transient voltages
Opis:
To reduce the losses of the power electronic inverter, the voltage slew rate (d u/d t) of the electric motors supplying voltage is increasing. As steep voltage slopes excite high frequencies in the megahertz range, transient phenomena in the winding of the electrical machine occur. To design the insulation system, the maximum electric potential difference between the conducting elements must be predicted. General design rules can lead to a significant overengineering of the interturn insulation, particularly when considering smaller stators with a known wire distribution. Therefore, two different winding topologies are studied comparing the voltage distribution in a round-wire winding and a winding with preformed coils.
Źródło:
Archives of Electrical Engineering; 2022, 71, 4; 865--880
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of Agar-Silica Aerogel Nanocomposite Films
Autorzy:
Lee, Min-Jin
Jung, Hyun-Ah
Lee, Kyong-Jin
Hwang, Haejin
Powiązania:
https://bibliotekanauki.pl/articles/356287.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermal insulation film
silica aerogel
agar
thermal conductivity
transmittance
Opis:
In this study, agar-based nanocomposite films containing ultra-porous silica aerogel particles were fabricated by gel casting using an aqueous agar/silica aerogel slurry. The silica aerogel particles did not show significant agglomeration and were homogeneously distributed in the agar matrix. Transmission electron microscopy observations demonstrated that the silica aerogel particles had a mesoporous microstructure and their pores were not incorporated into the agar polymer molecules. The thermal conductivities of the agar and agar/5wt.% silica aerogel nanocomposite films were 0.36 and 0.20 W·m-1·K-1, respectively. The transmittance of the agar films did not decrease upon the addition of silica aerogel particles into them. This can be attributed to the anti-reflection effect of silica aerogel particles.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 851-855
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of conductive particle contaminationon the insulation system of rotating electrical machines with direct oil cooling
Autorzy:
Yang, Liguo
Pauli, Florian
Zhang, Shimin
Hambrecht, Fabian
Hameyer, Kay
Powiązania:
https://bibliotekanauki.pl/articles/2135735.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cooling
insulation system
particle contamination
partial discharge
surface resistance
Opis:
An integration of the electrical machine and the gearbox is attracting particular attention for the design of modern electric and hybrid drive trains, since it saves overall space and subsequently increases the power density. Another benefit of a high level of integration is that it enables a combined application of oils as both cooling fluid for the electrical machine and as lubrication fluid for the transmission system. In this way, the power density of the integrated drive train can be further increased. During the oil cycling, conductive contaminations may be introduced and subsequently have an influence on the function of the insulation system of the electrical machine. In the present work, the influences of the cooling oil and its conductive contaminations, conductive particles as well as their combination with humidity, on the electrical and dielectric properties of the insulation system are studied. The results show that by application of the cooling oil, the partial discharge inception voltage (PDIV) of the winding insulation increases significantly so that an electrical breakdown is prone to happen before a partial discharge (PD) occurs. With increasing particle contamination, the PDIV of the insulation system decreases significantly, while the capacitance increases. Besides, conductive particles and humidity decrease the surface resistance and surface breakdown voltage of the insulation papers significantly. The results indicate that the conductive particle contaminations can play an important role for the electrical degradation of the insulation system.
Źródło:
Archives of Electrical Engineering; 2022, 71, 3; 789--804
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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