Electromagnetic forces on contacts

Kulas, S.; Kolimas, Łukasz; Piskala, M.

doi:10.1109/upec.2008.4651638

Cited by 4 publications

(6 citation statements)

References 6 publications

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“…The contact blow-open process is a complex one, dependent on the pre-open phenomena [25] and on electrodynamic forces [15,22,26,27]. The current thrusts of research are the effects of blow-open contact bounce on contact welding and the phenomena behind it [4,5,13,26].…”

Section: Resultsmentioning

confidence: 99%

“…The current thrusts of research are the effects of blow-open contact bounce on contact welding and the phenomena behind it [4,5,13,26]. Studies regarding the influence of electrodynamic forces [15,28] and high current [29,30] do not cover the electrodynamic action of the operating relay coil. Presented research shows the relationship between the electrodynamic blow-open of contacts under high fault currents and the static contact force trying to prevent the contacts from opening.…”

Section: Resultsmentioning

confidence: 99%

“…Studies of electrodynamic forces that can act on electrical contacts have provided insight as to how these phenomena work. Both theoretical and experimental results are available that can, in some manner, describe these phenomena [15]. They describe the electrodynamic force generated by current flowing between contacts, but they do not link all force components.…”

Section: Introductionmentioning

confidence: 99%

“…Research into the issue of electrodynamic bounce and electrodynamics in electrical contacts, focuses mainly on a single component of this force. It is focused mostly on the repulsion force between contacts [15] or force generated by electric arc [21]. Other studies attempt to describe these phenomena but only for very high currents, with a magnitude of kiloamperes [1,2,16].…”

Section: Introductionmentioning

confidence: 99%

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Electrodynamic Contact Bounce Induced by Fault Current in Low-Voltage Relays

et al. 2019

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Due to fault currents occurring in electrical installations, high electromagnetic force values may be induced in current paths of low-voltage electromagnetic relays. This force may lead to an electromagnetic bounce that will further result in an electric arc ignition between contacts, and under some circumstances, it will result in contact welding. For the proper exploitation of relays, the threshold value of the maximum current, and thus the electrodynamic force, should be known. This force depends on several factors, including: contact materials, dimensions of relay current paths, relay electromagnetic coil, etc. This paper presents the results of calculations and an experiment on electromagnetic forces, which cover these factors. A static closing force, acting on the contacts, and the fault current were measured. As a result, values of the force and current threshold were obtained, which inform when an electrodynamic bounce may occur. The obtained result may be used in designing contact rivets and relay current paths together with the selection of adequate fault protection devices.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrodynamic Contact Bounce Induced by Fault Current in Low-Voltage Relays

et al. 2019

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“…This method relies on replacing one busbar of heterogeneous current density by a series of separate smaller current circuits of constant current density [5]. The application of the Biot-Savart law gives the possibility of determining the magnetic induction at any point of space caused by the flow of current through the element of the conductor [6]. Furthermore, calculations of the magnetic induction value allow determining the electrodynamic forces acting in the conductor system [7], which is shown in Figure 1 below.…”

Section: Introductionmentioning

confidence: 99%

Calculations of Electrodynamic Forces in Three-Phase Asymmetric Busbar System with the Use of FEM

et al. 2020

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Proper busbar selection based on analytical calculations is of great importance in terms of power grid functioning and its safe usage. Experimental tests concerning busbars are very expensive and difficult to be executed. Therefore, the great advantage for setting the valid parameters for busbar systems components are analytical calculations supported by FEM (finite element method) modelling and analysis. Determining electrodynamic forces in busbar systems tends to be crucial with regard to subsidiary, dependent parameters. In this paper analytical calculations of asymmetric three-phase busbar system were carried out. Key parameters, like maximal electrodynamic forces value, mechanical strength value, busbar natural frequency, etc., were calculated. Calculations were conducted with an ANSYS model of a parallel asymmetric busbar system, which confirmed the obtained results. Moreover, showing that a model based on finite elements tends to be very helpful in the selection of unusually-shaped busbars in various electrotechnical applications, like switchgear.

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Electrodynamic Forces in a High Voltage Circuit Breakers With Tulip Contact System—FEM Simulations

et al. 2022

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Paper concerns the effects of electrodynamic forces that act on the contacts of the tulip contact system that is often implemented in high voltage circuit breakers. The high voltage circuit breaker often consists of two such systems. One of the systems is treated as an arcing one -made of tungsten coated elements. Capable of implementing the phenomenon of thermal-expansion. The second is made of one or two crown laces. The first system consists of a single piece of large mass, cut in such a way as to obtain the effect of increasing the contact surface. The second is a system, often of several dozen contacts, so as to increase the contact area and reduce the transition resistance. The main problem of actual validation through dynamic measurements (electrodynamic forces) is the specificity of the circuit breaker operation. The contact system is located directly in the switch chamber filled with CO2 or SF6 gas. Hence, tests under normal working conditions are very difficult -even impossible. Therefore, the authors proposed employment of FEM (Finite Element Method) in order to obtain values of electrodynamic forces acting on the contact system by executing the detailed 3D coupled simulation. The analysis of the results brought interesting conclusions that concerned operation of such contact layouts in short circuit conditions.

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Electromagnetic forces on contacts

Cited by 4 publications

References 6 publications

Electrodynamic Contact Bounce Induced by Fault Current in Low-Voltage Relays

Electrodynamic Contact Bounce Induced by Fault Current in Low-Voltage Relays

Calculations of Electrodynamic Forces in Three-Phase Asymmetric Busbar System with the Use of FEM

Electrodynamic Forces in a High Voltage Circuit Breakers With Tulip Contact System—FEM Simulations

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