Determination of the Causes of Copper Wires Beads after Fire in Vehicles

2022 ◽  
Vol 1049 ◽  
pp. 311-316
Author(s):  
Andrei Yu. Mokryak ◽  
Anna V. Mokryak ◽  
Soslan V. Skodtaev ◽  
Tatiana V. Safonova
Keyword(s):  
Power Supply System ◽  
Short Circuit ◽  
Experimental Simulation ◽  
Motor Vehicles ◽  
Metallographic Analysis ◽  
Single Wire ◽  
Dc Power ◽  
Electrical Wiring ◽  
Electrical Installation

An electrical installation that simulates an automobile DC power supply system with a voltage of 12 V has been created. An experimental simulation of a short circuit at currents up to 400 A on copper multi-wire and single-wire conductors under normal environmental conditions is carried out. The copper wires beads were annealed in a furnace at temperatures from 700 to 1000 °C for 20, 40 and 60 minutes. Metallographic analysis of copper wires beads was carried out. The temperatures and times that of at which the signs of short circuit and overcurrent are destroyed has been revealed. Obtained results contribute to improvement evidence’s researching in the fire investigation of motor vehicles electrical wiring after a fire. Keywords: Arc beads, Copper, Metallographic analysis, Electrical Short Circuit, Wires.

An Extended Model of Light Railway System Used in Analysis of Normal Operation and Fault Conditions

2014 ◽  
Author(s):  
Sorin Deleanu ◽  
Keith Forman ◽  
David C. Carpenter ◽  
Calin Munteanu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Short Circuit ◽  
Operating Conditions ◽  
Normal Operation ◽  
Dc Power ◽  
Railway System ◽  
Analytical Approaches ◽  
Element Method

The paper provides a description of the analysis of a Light Railway System for two configurations: - Rails above the ground and catenary supply - Track in a tunnel and power rail supply. Finite Element Method (FEM) analysis is compared to classical analytical approaches by Carson, Pollaczek, Bickford and Tylavsky. Reviews of methods to determine self and mutual impedance for electrified railroads are provided. The solution of finite element method (FEM) applied for the determination of impedance for the two traction rail and catenary configuration, modeled and examined, consists of computational analysis based upon minimizing the energy of electromagnetic field. The analytic impedance models are built on Carson-Pollaczek–Bickford equations, adjusted by Tylavsky, for two situations: when the ground is perfectly insulated and when considering the earth return current. The railway track – catenary is integrated in a system containing the model for traction substation(s) with DC power output and moving vehicle with induction motors, controlled using voltage inverters with pulse width modulation. The light transit train, supplied with a rectified DC power, is subjected to a significant harmonic content, which may affect the signal and control circuits. It is then shown that the power and signaling characteristics of the modelled system can predict the magnitude of the perturbation current for different frequencies, in normal operating conditions and in presence of faults as well. In many of the light transportation systems, from all types of faults, the DC short-circuit at the output of the power rectifiers used for energizing the power rail and/or catenary presents a special interest. This is because of two main reasons: the positions of the vehicle-loads are in continuous changing and, even if they operate from DC sources, the parent network is still of AC type. A key issue was the determination of the distributed parameters (resistances, inductances) of the running track and catenary, from experimental data and preliminary analytical and numerical calculations, followed by the analysis of their dependencies with the current magnitude and frequency response. A specific short-circuit study case is simulated when using a model of the traction system for the purpose of the DC fault current prediction. The paper concludes with a discussion of future developments and further work.

Determination of parameters of short circuit of power transformer by means of mathematical modeling

2017 ◽  
Vol 26 (102) ◽  
pp. 110-119
Author(s):  
D. S. Yarymbash, ◽  
◽  
S. T. Yarymbash, ◽  
T. E. Divchuk, ◽  
D. A. Litvinov
Keyword(s):  
Mathematical Modeling ◽  
Power Transformer ◽  
Short Circuit ◽  
Determination Of Parameters

scholarly journals Recatest—A Technique for Qualitative and Quantitative Assessment of Deferment and Degraded PVD Coatings and CVD Layers in the Deformed Area in the Scratch Test

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2625
Author(s):  
Piotr Domanowski ◽  
Marek Betiuk
Keyword(s):  
Scratch Test ◽  
Metallographic Analysis ◽  
Tool Steels ◽  
Test Device ◽  
Coating Structure ◽  
Testing Technique ◽  
Coating Materials ◽  
Qualitative And Quantitative ◽  
Quantitative Parameters

The purpose of the paper is to present a new Recatest testing technique which uses a series of abrasions within a scratch and its innovative application to describe selected quantitative parameters of locally, plastically deformed substrate and coating materials detected on the spherical microsection in the scratch test. The exposed material structures are subject to a metallographic analysis which allows for the determination of the quantitative parameters, which in turn allow for a description of the change in dynamics of the coating structure within the scratch area as a function of load. These parameters include scratch depth (hs), coating thickness (h1), flash height (hoc, hos), depth of intended material (hd), material depth under scratch (hcp), and material depth under coating (hdb). The paper also includes a description of the Recalo test device designed by the authors, which is used to make a series of spherical abrasion traces on the scratch surface. Recalo is dedicated to the Recatest technique. The analysed material was the CrN/CrCN/HS6-5-2, AlCrN -Alcrona-Balinit/D2 coatings deposited on tool steels.

III. An experimental determination of the velocity of sound

1872 ◽  
Vol 20 (130-138) ◽  
pp. 34-35
Keyword(s):  
Experimental Determination ◽  
Cape Town ◽  
The Other ◽  
Velocity Of Sound ◽  
Successful Operation ◽  
Single Wire ◽  
Galvanic Current ◽  
Royal Observatory ◽  
Port Elizabeth

A galvanic current passes from the batteries at the Royal Observatory, Cape Town, at 1 o’clock, and discharges a gun at the Castle, and through relays drops a time-ball at Port Elizabeth. It appeared to the author that a valuable determination of the velocity of sound might be obtained by measuring upon the chronograph of the Observatory the interval between the time of the sound reaching some point near the gun and that of its arrival at the Observatory. As there is only a single wire between the Observatory and Cape Town, some little difficulty was experienced in making the necessary arrangements, without any interference with the 1 o’clock current to Port Elizabeth; but this difficulty was overcome by a plan which the author describes, and which was brought into successful operation on Feb. 27, 1871. The experiments could not have been carried out, on account of the encroachment they would have made on the time of the Observatory staff, had it not been for the assistance of J. Den, Esq., the acting manager of the Cape Telegraph Company, to whom the author is indebted for the preparation of a good earth-connexion near the gun, for permission to Mr. Kirby, a gentleman attached to the telegraph office, to assist in the experiments, and for a general superintendence of the arrangements at Cape Town. The observed times of hearing the sound were recorded on the chronograph by two observers, situated one (Mr. Kirby) at a distance of 641 feet from the gun, the other (Mr. Mann) at the Observatory, at a distance of 15,449 feet from the gun. The former distance was sufficient to allow the connexion of the main wire to be broken at the telegraph office after the gun had been fired, but before the sound reached the first observer.

DC Power Supply System for Autonomous Objects

2021 ◽  
Author(s):  
Andrey S. Kharitonov ◽  
Regina Yu. Sarakhanova ◽  
Oleg N. Bodin ◽  
Yuri N. Zolotukhin ◽  
Sergey A. Kharitonov
Keyword(s):  
Power Supply ◽  
Power Supply System ◽  
Supply System ◽  
Dc Power ◽  
Dc Power Supply ◽  
Autonomous Objects
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