Impulse current withstand capability of coaxial cables in high current applications

2008 ◽  
Author(s):  
M. Romheld ◽  
W. Hartmann
Keyword(s):  
High Current ◽  
Impulse Current

Robust electrical contacts integrating a liquid metal bridge for mechanical switches

2021 ◽  
Author(s):  
Xiaonan Zhu ◽  
Fei Yang ◽  
Haoran Wang ◽  
Siyuan Zhao ◽  
Yifei Wu ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Electrical Contacts ◽  
Solid Surfaces ◽  
Uniform Structure ◽  
High Current ◽  
Electrodynamic Force ◽  
Volume Force ◽  
Physical Mechanisms ◽  
Simulation Results ◽  
Impulse Current

Abstract Intrinsic roughness of solid surfaces causes a series of inevitable shortcomings in the use of mechanical electrical contacts, among which one of the most fatal is the repulsive electrodynamic force arising from high currents. A large contact force coming from a heavy holding mechanism helps to suppress the repulsive effect whereas the mechanism consumes energy and remains to be challenging for a compact switching device. Here, a liquid metal (LM) bridge is introduced to wet solid electrodes to eliminate contact issues. Four instability patterns induced by the electromagnetic pinch effect are identified to characterize LM bridge’s response to high currents. Simulation results reveal that an inner vortex caused by uneven distributions of current density and electrodynamic volume force leads to the rupture of a necked LM bridge. With a uniform structure, a cylindrical LM bridge is proved to be robust with respect to an impulse current higher than 10 kA, exceeding a commercial compact relay by a factor of more than 10 in terms of current withstand performance. Our research facilitates compact and energy-saving switch equipment and has a potential to realize arbitrary desired levels of high current withstand without the use of a holding mechanism. This paper also offers deep insights into the high current applications of LM from the perspective of fluid related physical mechanisms.

scholarly journals On the Characterisations of the Impulse Breakdown in High Resistivity Soils by Field Testing

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2401
Author(s):  
Abdul Wali Abdul Ali ◽  
Normiza Mohamad Nor
Keyword(s):  
Steady State ◽  
Breakdown Voltage ◽  
Field Testing ◽  
High Resistivity ◽  
High Current ◽  
Current Generator ◽  
Current Impulse ◽  
Negative Impulse ◽  
Impulse Current Generator ◽  
Impulse Current

This paper presents experimental results of high-current impulse tests on six ground electrode configurations. A high impulse current generator is employed to inject different magnitudes of current into these rod electrodes, under both positive and negative impulse polarities. The effect of increasing the number of rod electrodes, hence the resistance at DC or steady-state (RDC), on the impulse response of ground electrodes is analysed. From the analysis of the results, it was found that the larger the size of rod electrodes, the less current-dependent Zimpulse becomes. The percentage of reduction of impulse impedance, Zimpulse from its steady state, and RDC values are found to be independent of impulse polarity. However, as the voltage magnitudes were increased, an occurrence of breakdown was seen, with higher breakdown voltage seen in negative impulse polarity in comparison to positive impulse polarity. Relatively, the higher the breakdown voltage is, seen in the ground electrodes subjected to negative polarity, the faster the time to breakdown is.

scholarly journals Investigations on the Performance of a New Grounding Device with Spike Rods under High Magnitude Current Conditions

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1138 ◽  
Author(s):  
Abdul Abdul Ali ◽  
Nurul Ahmad ◽  
Normiza Mohamad Nor ◽  
Muhd Reffin ◽  
Syarifah Amanina Syed Abdullah
Keyword(s):  
Field Measurements ◽  
Test Results ◽  
High Current ◽  
The Earth ◽  
High Magnitude ◽  
State Test ◽  
Earthing Systems ◽  
Steady State Test ◽  
Impulse Current ◽  
Earth Electrode

In many publications, the characteristics of practical earthing systems were investigated under conditions involving fast-impulse currents of different magnitudes by field measurements. However, as generally known, in practice the transient current can normally reach several tens of kiloamperes. This paper therefore aimed to investigate the characteristics of a new electrode for grounding systems under high current magnitude conditions, and compare it with steady-state test results. The earth electrodes were installed in low resistivity test media, so that high impulse current magnitudes can be achieved. The effects of impulse polarity and earth electrode’s geometry of a new earth electrode were also quantified under high impulse conditions, at high currents (up to 16 kA).

Spatial resolution of X-ray microanalysis in thin foils

1978 ◽  
Vol 36 (1) ◽  
pp. 544-545
Author(s):  
R. Hutchings ◽  
I.P. Jones ◽  
M.H. Loretto ◽  
R.E. Smallman
Keyword(s):  
Spatial Resolution ◽  
Electron Probe ◽  
Beam Divergence ◽  
Inelastic Interaction ◽  
Specimen Thickness ◽  
High Current ◽  
Beam Spreading ◽  
X Ray ◽  
Thin Foils ◽  
Complex Calculation

There is increasing interest in X-ray microanalysis of thin specimens and the present paper attempts to define some of the factors which govern the spatial resolution of this type of microanalysis. One of these factors is the spreading of the electron probe as it is transmitted through the specimen. There will always be some beam-spreading with small electron probes, because of the inevitable beam divergence associated with small, high current probes; a lower limit to the spatial resolution is thus 2αst where 2αs is the beam divergence and t the specimen thickness.In addition there will of course be beam spreading caused by elastic and inelastic interaction between the electron beam and the specimen. The angle through which electrons are scattered by the various scattering processes can vary from zero to 180° and it is clearly a very complex calculation to determine the effective size of the beam as it propagates through the specimen.

Precipitation in silicon: Microanalysis

1988 ◽  
Vol 46 ◽  
pp. 474-475
Author(s):  
R.W. Carpenter
Keyword(s):  
Transition Metals ◽  
Spatial Resolution ◽  
Thin Foil ◽  
Precipitation Reaction ◽  
High Current ◽  
Reaction Products ◽  
Carbon And Nitrogen ◽  
Dielectric Layers ◽  
Precipitation Processes ◽  
Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

Defect reduction in oxygen implanted silicon-on-insulator material during high-temperature annealing

1989 ◽  
Vol 47 ◽  
pp. 604-605
Author(s):  
P. Roitman ◽  
B. Cordts ◽  
S. Visitserngtrakul ◽  
S.J. Krause
Keyword(s):  
High Temperature ◽  
Annealing Temperature ◽  
Silicon On Insulator ◽  
High Dose ◽  
High Temperature Annealing ◽  
High Current ◽  
Defect Reduction ◽  
Annealing Step ◽  
Multiple Cycle ◽  
Defect Densities

Synthesis of a thin, buried dielectric layer to form a silicon-on-insulator (SOI) material by high dose oxygen implantation (SIMOX – Separation by IMplanted Oxygen) is becoming an important technology due to the advent of high current (200 mA) oxygen implanters. Recently, reductions in defect densities from 109 cm−2 down to 107 cm−2 or less have been reported. They were achieved with a final high temperature annealing step (1300°C – 1400°C) in conjunction with: a) high temperature implantation or; b) channeling implantation or; c) multiple cycle implantation. However, the processes and conditions for reduction and elimination of precipitates and defects during high temperature annealing are not well understood. In this work we have studied the effect of annealing temperature on defect and precipitate reduction for SIMOX samples which were processed first with high temperature, high current implantation followed by high temperature annealing.

CONDUCTIVITY MEASUREMENTS OF HIGH CURRENT, HIGH PRESSURE DISCHARGES

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-303-C7-304
Author(s):  
M. Skowronek ◽  
L. Giry ◽  
Vu Tien Gia ◽  
P. Romeas
Keyword(s):  
High Pressure ◽  
High Current ◽  
Conductivity Measurements

HIGH-CURRENT DIFFUSE DISCHARGE WITH THE EXPLOSIVE CATHODE PROCESS

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-281-C7-282
Author(s):  
A. P. Kchuzeev ◽  
Yu. D. Korolev ◽  
V. A. Kuzmin ◽  
G. A. Mesyats ◽  
V. P. Rotshtein ◽  
...  
Keyword(s):  
High Current ◽  
Diffuse Discharge ◽  
Cathode Process

Micropinch in a high-current diode

1979 ◽  
Vol 129 (9) ◽  
pp. 87 ◽  
Author(s):  
E.D. Korop ◽  
B.E. Meierovich ◽  
Yu.V. Sidel'nikov ◽  
S.T. Sukhorukov
Keyword(s):  
High Current
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