摘要 :
Modern theoretical notations on electrical breakdown in vacuum consider cathode triggering mechanisms to be most responsible on short-pulsed (< 1μs) breakdowns while anode mechanisms to be responsible in a part on dc and long-pulsed breakdowns. Following those notations, we tried to reveal conditions at which either mechanism steps aside to another one. The study involved several experimental techniques including the anode-probe surface scanning, pulsed electron-beam surface melting in vacuum for surface cleaning, and intentional dust particle contamination of electrode surfaces. Breakdown tests were performed using a pulser capable of producing 220 kV quasi-square pulses that were adjustable to ～ 30 to 80 ns pulse length. Our experiments showed that cathode emission sites are responsible for breakdowns at relatively low hold-off fields. At higher electric fields of up to 1 MV/cm, the anode share in the mechanism of triggering breakdown becomes probably more significant than the cathode mechanism....
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Modern theoretical notations on electrical breakdown in vacuum consider cathode triggering mechanisms to be most responsible on short-pulsed (< 1μs) breakdowns while anode mechanisms to be responsible in a part on dc and long-pulsed breakdowns. Following those notations, we tried to reveal conditions at which either mechanism steps aside to another one. The study involved several experimental techniques including the anode-probe surface scanning, pulsed electron-beam surface melting in vacuum for surface cleaning, and intentional dust particle contamination of electrode surfaces. Breakdown tests were performed using a pulser capable of producing 220 kV quasi-square pulses that were adjustable to ～ 30 to 80 ns pulse length. Our experiments showed that cathode emission sites are responsible for breakdowns at relatively low hold-off fields. At higher electric fields of up to 1 MV/cm, the anode share in the mechanism of triggering breakdown becomes probably more significant than the cathode mechanism.
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In this paper, the pressure monitor method of vacuum glazing was studied by using the Micro-Pirani vacuum sensor. The limited condition of the Micro-Pirani vacuum sensor for vacuum glazing was given. The detail structure of the im...
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In this paper, the pressure monitor method of vacuum glazing was studied by using the Micro-Pirani vacuum sensor. The limited condition of the Micro-Pirani vacuum sensor for vacuum glazing was given. The detail structure of the improved Micro-Pirani vacuum sensor is shown. The finite element method was used to simulate the vacuum sensor performance. The max temperature of the heater is increased with the heater power by the lining rule. The max temperature is affected by the gas pressure obviously. The wonderful sensitivity is shown between 0.1 Pa and 1 Pa that is enough to check the thermal insulation performance affected by gas pressure. The vacuum glazing is used in different environment, so the heatsink temperature is varied with the environment temperature, which affects the max heater temperature.
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in anii 1990, companiile de top Leybold si Degussa si-au externalizat diviziile "Topirea in vid" si "Tratamentul termic in vid" si au infiintat pentru a stabili compania LeyboldDurferrit. in 1994, Aichelin s-a unit pentru o scurta...
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in anii 1990, companiile de top Leybold si Degussa si-au externalizat diviziile "Topirea in vid" si "Tratamentul termic in vid" si au infiintat pentru a stabili compania LeyboldDurferrit. in 1994, Aichelin s-a unit pentru o scurta perioada de timp cu LeyboldDirferrit si a luat fiinta compania ALD. Din 2007 ALD a devenit membru al "Grupului de Metalurgie Avansata" AMG" care este cotat la Bursa de Marfuri din Olanda. Grupul AMG Group este compus din doua divizii principale:"Materiale" si "Inginerie". Divizia de materiale este format din mai multe companii care produc materiale, cum ar fi grafit natural, siliciu, tantal etc. ALD este parte a diviziei de inginerie, al carei scop este de a dezvolta si produce cuptoare de topire in vid pentru rafinarea materialelor. ALD produce, de asemenea, cuptoare de tratament termic pentru carburarea la presiune scazuta a angrenajelor si arborilor, in vederea imbunatatirii calitatii acestora. Astazi, ALD este lider tehnic global in domeniul tehnologiei in vid si detine mai multe brevete. in cele ce urmeaza sunt prezentate, principalele concepte, echipamente si tehnologii de vid produse de ALD.
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In the 1990s the leading companies Leybold and Degussa outsourced the ,,Vacuum Melting" and ,”Vacuum Heat Treatment" divisions to establish the company LeyboldDurferrit. In 1994 Aichelin joined LeyboldDurferrit for a short time a...
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In the 1990s the leading companies Leybold and Degussa outsourced the ,,Vacuum Melting" and ,”Vacuum Heat Treatment" divisions to establish the company LeyboldDurferrit. In 1994 Aichelin joined LeyboldDurferrit for a short time and the company name ALD was born. Since 2007 ALD has been a member of the Advance Metallurgical Group "AMG", which is listed on the Netherland Stock Exchange. The AMG Group consists of two major divisions: "Materials" and "Engineering". The materials division consists of several mining companies which produce materials such as natural graphite, silicon, tantalum etc. ALD is part of the engineering division, whose aim is to develop and produce vacuum melting furnaces for the refining of materials. ALD also produces heat treatment furnaces for the low pressure carburization of gears and shafts in order to improve their quality .Today, ALD is the global technical leader in vacuum technology and holds many patents. In this paper, the main ALD vacuum concepts, installations and technologies are shown.
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The article presents the detailed construction and capabilities of a research station for the diagnosis and testing of vacuum interrupters used in medium voltage electrical switching devices. The correct functioning of the stand h...
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The article presents the detailed construction and capabilities of a research station for the diagnosis and testing of vacuum interrupters used in medium voltage electrical switching devices. The correct functioning of the stand has been confirmed by conducting a number of tests on the electrical strength of the MV switchgear vacuum interrupter type HVKR 24/400.
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The vacuum field is considered as a force field, which consists of particles moving at speeds of the order of the speed of light, such as neutrinos, photons and charged cosmic rays. This distinguishes it from the classical static ...
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The vacuum field is considered as a force field, which consists of particles moving at speeds of the order of the speed of light, such as neutrinos, photons and charged cosmic rays. This distinguishes it from the classical static ether and some models of the quantum vacuum. In the presented model the occurrence of gravitational and electromagnetic force is substantiated, some vacuum field parameters are predicted, the sources that generate the vacuum field are suggested based on the theory of infinite nesting of matter.
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A new vacuum seal for a rectangular flange used in r.f. equipments, was developed. The vacuum seal consists of a recess with a flat surface, machined into a rectangular flange, a rectangular metal gasket with a raised projection o...
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A new vacuum seal for a rectangular flange used in r.f. equipments, was developed. The vacuum seal consists of a recess with a flat surface, machined into a rectangular flange, a rectangular metal gasket with a raised projection on one face, and a mating flange with a recess and raised projection. No leak greater than 1 × 10~(-10) Pa m~3/s was found in leak tests, before and after baking cycles (100 °C, 12 h).
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The development of power grid infrastructure and increasingly stringent environmental regulations have intensified work, carried out by researchers and electrical equipment manufacturers, to develop innovative gas-insulated, envir...
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The development of power grid infrastructure and increasingly stringent environmental regulations have intensified work, carried out by researchers and electrical equipment manufacturers, to develop innovative gas-insulated, environmentally neutral devices. The emergence of new designs of circuit breakers and disconnectors, in which the resulting electric arc is extinguished in a vacuum environment, requires the development of appropriate techniques for diagnosing the chambers responsible for the dielectric parameters of the device. The following article presents an overview of the directions of development of diagnostic methods for medium-voltage vacuum switching equipment, which can potentially be used to develop a real-time pressure monitoring system that can be applied to vacuum switching equipment used in electrical infrastructure.
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There are two types of fluctuations in the quantum vacuum: type 1 vacuum fluctuations are on shell and can interact with matter in specific, limited ways that have observable consequences; type 2 vacuum fluctuations are off shell ...
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There are two types of fluctuations in the quantum vacuum: type 1 vacuum fluctuations are on shell and can interact with matter in specific, limited ways that have observable consequences; type 2 vacuum fluctuations are off shell and cannot interact with matter. A photon will polarize a type 1, bound, charged lepton-antilepton vacuum fluctuation in much the same manner that it would polarize a dielectric, suggesting the method used here for calculating the permittivity epsilon(0) congruent to (6 mu(0)/pi)(8e(2)/(h) over bar )2=9.10x10(-12) C/(Vm). The calculated value for epsilon(0) is 2.7% more than the accepted value. The permittivity of the vacuum, in turn, determines the speed c of light in the vacuum. Since the vacuum is at rest with respect to every inertial frame of reference, c is the same in every inertial reference frame.
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A high-speed vacuum circuit breaker which forces the fault current to zero was investigated. The test circuit breaker consisted of a vacuum interrupter and a high-frequency current source. A vacuum interrupter with an axial magnet...
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A high-speed vacuum circuit breaker which forces the fault current to zero was investigated. The test circuit breaker consisted of a vacuum interrupter and a high-frequency current source. A vacuum interrupter with an axial magnetic field electrode and a disk-shaped electrode was tested. The arcing period of the high-speed vacuum circuit breaker is much shorter than that of a conventional circuit breaker. The arc behavior of the test electrodes immediately after the contact separation was observed by a high-speed video recorder. The relation between the current waveform just before the current zero point and the interruption ability was investigated experimentally by varying the high-frequency current source. The results demonstrate the interruption ability and the arc behavior of the high-speed vacuum circuit breaker. Effective current interruption is made possible by a low current period just before the current zero point, even though the arcing time is short and the arc is concentrated.
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