The Application of Relay in Electrical Engineering and Its Automation Low Voltage Electrical Apparatus is Briefly Discussed

2021 ◽  
Keyword(s):  
Low Voltage ◽  
Electrical Engineering ◽  
Electrical Apparatus

scholarly journals Thyristor Arc Eliminator for Protection of Low Voltage Electrical Equipment

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2749 ◽  
Author(s):  
Karol Nowak ◽  
Jerzy Janiszewski ◽  
Grzegorz Dombek
Keyword(s):  
Lower Cost ◽  
Low Voltage ◽  
Short Circuit ◽  
Electrical Equipment ◽  
Power Network ◽  
System Operation ◽  
Test Circuit ◽  
Wide Range ◽  
Short Circuit Currents ◽  
Electrical Apparatus

The paper presents the layout of two opposing thyristors working as an Arc Eliminator (AE). The presented solution makes it possible to protect an electrical apparatus against the effects of an arcing fault. An Arc Eliminator is assumed to be a device cooperating with the protected apparatus. Thyristors were used because of their speed of operation and a relatively lower cost compared to other semiconductors with the same current-carrying capacity. The proposed solution, as one of the few currently available, makes it possible to eliminate the fault arc—both at short-circuit currents and current values to which overcurrent protections do not react. A test circuit was designed and made to study the effectiveness of the thyristor arc eliminator. A series of tests was carried out with variable impedance in the arc branch, including the influence of circuit inductance on arc time. It was found that the thyristor arc eliminator effectively protects devices powered from a low voltage power network against the effects of a fault or arc fault. The correctness of system operation for a wide range of impedance changes in the circuit feeding the arc location was demonstrated.

Study on Reliability of Control and Protective Switching Device

2012 ◽  
Vol 229-231 ◽  
pp. 819-823
Author(s):  
Shi Ze Huang ◽  
Qi Yi Guo ◽  
Jing Tai Hu ◽  
Min Juan Zhang ◽  
Ya Jie He
Keyword(s):  
Failure Modes ◽  
Low Voltage ◽  
Research Work ◽  
National Standard ◽  
Social Benefits ◽  
Switching Device ◽  
Industry Standard ◽  
First Time ◽  
Operation Characteristics ◽  
Electrical Apparatus

After introducing the new low-voltage protective electrical apparatus—Control and Protective Switching Device (CPS), there came to the importance and social benefits of its reliability. According to the study on CPS’s operation characteristics and failure modes, along with the current national standard and related industry standard, the two reliability indexes were proposed to measure CPS’s reliability for the first time, and the reliability compliance test plans were also provided. All the study did provide a reference for the reliability research work of CPS.

A Lecture Package for School Pupils to Promote Electrical Engineering

1978 ◽  
Vol 15 (2) ◽  
pp. 101-107
Author(s):  
T. E. Price ◽  
M. C. Hately
Keyword(s):  
Electrical Engineering ◽  
Career Opportunities ◽  
Electrical Apparatus ◽  
School Curricula

Career talks form an important part of many school curricula. This article describes a lecture package of particular interest to school-chlidren. It has been successfully used for illustrating the career opportunities in electrical engineering and is based on slides and simple pieces of electrical apparatus which the pupils are able to handle.

scholarly journals Resistance change of contact groups of low-voltage electrical apparatus: Determining the laws

Vestnik MGTU ◽  
2021 ◽  
Vol 24 (4) ◽  
pp. 350-360
Author(s):  
E. I. Gracheva ◽  
A. N. Gorlov ◽  
A. N. Alimova ◽  
P. P. Mukhanova
Keyword(s):  
Low Voltage ◽  
Methodological Approach ◽  
Experimental Studies ◽  
Packet Switches ◽  
Circuit Breakers ◽  
Resistance Change ◽  
Design Elements ◽  
Electrical Devices ◽  
Resistance Value ◽  
Electrical Apparatus

The main Russian and foreign manufacturers of low-voltage electrical devices - circuit breakers, fuses, magnetic starters, knife switches and packet switches are presented. The data of experiments for determining the resistance values of contact groups of low-voltage switching equipment are considered. The design features of the devices that determine the value of the resistances of the power circuits of low-voltage equipment are investigated and a classification is proposed depending on the design elements of the devices. A methodological approach and an algorithm for experiments and detailed analysis of the contact groups of devices are given. Experimental schemes for the study of contact groups are proposed. The data of the conducted experiments on the study of contact groups and the resistance values as a function of the flowing currents are shown. During the experiments it is revealed that the value of the resistance of the contacts changes depending on the value, type and time of exposure to current within +/-5 %. The laws that characterize the ratio of the resistance values of the structural components of devices (contact systems, thermal relay, coil of the maximum relay) have been revealed and defined. Empirical expressions and graphical dependences of the resistances of contacts and contact systems are obtained as a function of the magnitude of the rated currents of low-voltage contact equipment. The minimum sample size of the number of devices during experimental research is determined, sufficient to calculate the mathematical expectation of the resistances of the contact connections of the devices with a given accuracy. As a result of experimental studies, it is revealed that the resistance value of contacts and contact joints can increase during operation by 2-2.5 times. The established dependences of the change in contact resistance can be used to predict the technical state of electrical installations of intrashop low-voltage networks, to clarify the amount of electricity losses in shop networks up to 1 kV, and can also be used as an additional regulation for maintenance and scheduled preventive maintenance.

Arthur Prince Chattock, 1860 - 1934

1934 ◽  
Vol 1 (3) ◽  
pp. 292-298
Keyword(s):  
Electrical Engineering ◽  
Royal Institution ◽  
University College ◽  
The Future ◽  
Electrical Engineers ◽  
Electrical Apparatus

Arthur Prince Chattock died at his home in Clifton, Bristol, on July 1, 1934. He was born on August 14, 1860, at Solihull, Warwickshire, a county with which his family had been identified for many generations. He was the eldest of a family of seven, one of his brothers being R. A. Chattock, M.Sc., President of the Institution of Electrical Engineers in 1925. His schooldays were spent in London at University College School. As a boy he showed an early interest in anything mechanical. Greatly stimulated by such events as the Christmas lectures of the Royal Institution, he made his own electrical apparatus and repeated experiments he had seen. He also wrote plays, erected a stage with drop scenes and gas footlights and made all the dresses for family theatricals. At seventeen he went abroad for two years to Dunkerque and Stuttgart mainly to study languages. At this age he was imbued with the idea of taking up electrical engineering for monetary reasons, but in the hope that sooner or later he would be in a position to abandon it and devote his life to the study of the fundamental phenomena of electricity in the future importance of which he had profound faith.

3D Thermal Analysis of a Power Supply Busbar Structure

2010 ◽  
Author(s):  
Adrian Plesca ◽  
Alina Scintee
Keyword(s):  
Thermal Analysis ◽  
Power Supply ◽  
Low Voltage ◽  
Circuit Breaker ◽  
Convective Heat Exchange ◽  
Point Of View ◽  
Circuit Breakers ◽  
Transient Thermal ◽  
Supply Systems ◽  
Electrical Apparatus

Busbar technology is more and more used to realize connections within power supply systems in answer to the need of compactness. The integrated problem on heat conduction and radiation-convective heat exchange describes the temperature regime in current conductors and current carrying busbars of power electrical apparatus such as circuit breakers or high breaking capacity fuses. Beside steady-state conditions, the transient thermal regime of busbar has an important influence upon whole power supply system from thermal behaviour point of view. Hence, a 3D thermal analysis of a power system including fuse, low voltage circuit breaker and busbars connections, using a specific software package based on Finite Element Method, has been done. From 3D thermal modelling and simulations, the thermal transient impedance for the busbar has been computed. This allows a better correlation between protection characteristics of the fuse and circuit breaker and busbar design.

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