The Molten Metal Bridge Stage of Opening Electrical Contacts

Koren, P.; Nahemow, M. D.; Slade, Paul G.

doi:10.1109/tphp.1975.1135030

Cited by 23 publications

(9 citation statements)

References 7 publications

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“…The contacts can be divided into three regimes: the initial melting period, a stable period and an unstable period during which it eventually ruptures. This conclusion is consistent with the research result of P. Koren [24] . It can be observed from the experiment that the shape of the molten bridge is pier rough in its initial formation stage, then the shape develops into cylindrical type with the increase of breaking distance of contact pair, and the shape becomes dumbbell when the molten bridge is in the period of instability until its rupture.…”

Section: Analysis On the Observation Results Of Molten Bridges Behaviorsupporting

confidence: 94%

High Speed Imaging Observation on Molten Bridge of AgSnO 2 Electrical Contact Material

Chen

Song

Muyang

et al. 2017

Rare Metal Materials and Engineering

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An electrical contact-high speed imaging experimental system was developed to study the basic characteristics and laws of molten bridges of AgSnO2 electrical contact material. On the one hand, the quantitative measurements were investigated by high speed imaging technology. On the other hand, the microstructure and element distribution on the surface of contacts were analyzed by SEM and EDS after molten bridges behavior. Results indicate that the evolution behavior of molten bridges of AgSnO2 contacts can be divided into three regimes: the initial melting period, a stable period and an unstable period during which it eventually ruptures. Molten bridges and arc can exist simultaneously in which there is some cooperation and competition relationship. The dimension of molten bridges of AgSnO2 contact material is micron scale, the diameter of molten bridges increases with the increase of current and the length decreases with the increase of current. In the process of the evolution behavior of molten bridges, the feature of molten bridges can be divided into three types: the pier, follow by the cylindrical and the dumbbell. The morphology and element distribution of the contacts surface are changed by the behavior of molten bridges.

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Section: Analysis On the Observation Results Of Molten Bridges Behaviorsupporting

confidence: 94%

High Speed Imaging Observation on Molten Bridge of AgSnO 2 Electrical Contact Material

Chen

Song

Muyang

et al. 2017

Rare Metal Materials and Engineering

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“…When the molten bridge is further heated, the bridge boils, metal vapor forms in the space between the contacts, and, finally, the arc discharge occurs. The minimum arc voltage with copper contacts in atmospheric air is known to be 12.19 V . The peak values of the contact voltage shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Dielectric strength of electric contacts after short‐duration arc in a hybrid DC circuit breaker

Nakayama

Zen

et al. 2020

IEEJ Transactions Elec Engng

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A hybrid direct current circuit breaker consisting of electrical contacts connected in parallel with a silicon carbide metal oxide semiconductor field‐effect transistor semiconductor device is capable of operating with low energy loss and high short‐circuit tolerance. It features a short‐duration arc discharge during current commutation; however, how the arc affects the dielectric strength between the contacts is not yet clear. This study conducts a quantitative evaluation of the dielectric strength after a short‐duration arc commutation. It is shown that the dielectric strength decreases after the arc commutation, and the breakdown electric field decreases as the arc duration increases. These results suggest that the existence of metal vapor and an increase in contact erosion caused by the commutation arc lower the dielectric strength of the electric contacts, in addition to the known effects of temperature rise of the contact surface and the air between contacts. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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“…Once the contact spot has melted and the contacts continue to separate, a molten bridge is formed between them. This molten bridge forms between them even at low currents [70], even when contacts open at high acceleration [112,113] and in vacuum [114]. The molten bridge lengthens, becomes unstable and finally ruptures releasing metal vapor in the contact gap.…”

Section: The Electric Arcmentioning

confidence: 99%

A Uniform Pressure Electromagnetic Actuator for Forming Flat Sheets

Kamal

Daehn

2006

Journal of Manufacturing Science and Engineering

139

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High velocity electromagnetic forming can lead to better formability along with additional benefits. The spatial distribution of forming pressure in electromagnetic forming can be controlled by the configuration of the actuator. A new type of actuator is discussed which gives a uniform pressure distribution in forming. It also provides a mechanically robust design and has a high efficiency for flat sheet forming. A simplified analysis of the actuator is presented that helps in the design of the system. Examples of uses of the actuator are then presented, specifically with regards to forming shapes and surface embossing. Some practical challenges in the design of the actuator are also addressed. This paper emphasizes the approaches and engineering calculations required to effectively use this actuator.

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The Molten Metal Bridge Stage of Opening Electrical Contacts

Cited by 23 publications

References 7 publications

High Speed Imaging Observation on Molten Bridge of AgSnO 2 Electrical Contact Material

High Speed Imaging Observation on Molten Bridge of AgSnO 2 Electrical Contact Material

Dielectric strength of electric contacts after short‐duration arc in a hybrid DC circuit breaker

A Uniform Pressure Electromagnetic Actuator for Forming Flat Sheets

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