如何正确理解、执行《耐电压测试仪》检定规程

本文对JJG795-2004《耐电压测试仪》检定规程中的部分新修订条款和执行过程中遇到的难点及疑问进行解释和说明,以便于计量检定人员加深对该规程的理解,正确执行规程。     

耐电压测试仪击穿电流设定误差的检定

在JJG795－1992耐电压测试仪试行检定规程（以下简称检定规程）中对击穿电流设定误差的检定是：如图1,将耐电压测试仪输出电压调至（500－1000河之间,然后将电阻箱阻值从大到小调整,直至耐电压测试仪发出报警或切断输出电压,记下此刻的电流值。击穿电流设定误差S;：互＿一工St＝H－X100％下式中：干一击穿电流三次测量值的平均值,L一击穿电流设定值。l——耐电压测试仪;H一电流毫安表;M一电阻箱。HB——高压变压器;D;。D。、D。、D。——整流二极管;R——击穿电流取样电阻;KZ——击穿电流控制电路。笔者曾经按以上方法…     

JJG795-2016《耐电压测试仪检定规程》解读

正一、修订背景JJG795-2004《耐电压测试仪检定规程》(以下简称"旧规程")已实施10余年,随着测试技术与制造水平的发展,有部分条款已不适应现行的检定工作。为此,在广泛征求意见和会议讨论的基础上,JJG795-2016《耐电压测试仪检定规程》(以下简称"新规程")于2015年修订完毕,并于2017年5月开始实施。为使检定人员更好地理解、执行规程,本文对规程的主要变化和执行规程中存在的难点及疑问加以     

耐压测试仪检定中容易出现的几个问题

耐压测试仪检定时有3个重要参数：输出电压、击穿报警电流和电压持续时间。笔者认为,击穿报警电流和电压持续时间这两个参数的检定容易出现以下问题：     

关于JJG795-2016《耐电压测试仪检定规程》的探讨

本文介绍了新近颁布的JJG795-2016《耐电压测试仪》检定规程在贯彻执行时对输出电压检定及检定点选择、泄漏电流和击穿报警电流的检定、输出电压持续时间的检定的理解和探讨     

指针式耐电压测试仪输出电压超差原因的分析

耐电压测试仪对安全防护起相当重要的作用,因此,耐电压测试仪的准确度要求比较严格。在JJG795-1992《耐电压测试仪(试行)》检定规程中,对此作出了明确规定,即输出电压、设定击穿电流、时间自动控制的误差都不应超过±5%。在这里主要对输出电压的误差进行讨论。JJG795-1992中规定,按下式计算输出电压各挡内每个测试点的输出电压相对误差Sn。Sn=UnV-nV n×100%(1)式中:U n——输出电压示值;Vn——静电电压表的测量值。从实际工作情况来看,现在企业生产所配置的耐电压测试仪有指针式的,也有数字式的。指针式耐电压测试仪所占比例约为40%…     

耐电压测试仪检定规程应切合实际

《耐电压测试仪检定规程》（JJG795—2004）已于2004年9月2日开始施行。该规程对旧规程（JJG795—1992）作了必要的完善、补充和修改，但在执行过程中，笔者觉得有些地方还应进一步改进，以更加切合实际需要。     

关于耐电压测试仪击穿报警电流和漏电流检定的探讨

从分析不同类型耐电压测试仪的击穿报警工作原理出发,讨论了击穿报警电流设定误差与漏电流示值误差的检定.分析了检定漏电流示值误差的必要性,以及现行检定规程中击穿报警电流检定方法的适用性,并对程控型耐电压测试仪的漏电流检定作了探讨.     

SODIM综合测试台测定普通滤棒吸阻的研究

为了研究不同长度吸阻测试单元对滤棒压降测量结果的影响,选择不同长度的滤棒作为实验样品,用三个不同长度套管的吸阻测试单元测定滤棒的吸阻。结果表明,不同长度的吸阻测试单元对测定普通成型纸滤棒的吸阻无明显的影响。     

几种特殊压力表检定的思考

本文探讨了几种特殊用途压力表的检定方法。     

Dielectric integrity of ion beam deposited aluminum oxide films in the 10-100 nm thickness range

Catastrophic electrical breakdown of thin Al₂O₃ reader gap films is becoming increasingly important for Giant Magneto-Resistive (GMR) recording heads. In this paper, we study the dielectric integrity of thin Al₂O₃ films in the 10-100 nm thickness range produced by ion beam deposition. The effects of substrate preparation, film thickness and assist beam parameters on electric breakdown are investigated. It was found that optimized films produced using an Al₂O₃ target break down at electric field strengths in the 8.5-9 MV/cm range.     

Effect of crystallographic dislocations on the reverse performance of 4H-SiC p-n diodes

A quantitative study was performed to investigate the impact of crystallographic dislocation defects, including screw dislocation, basal plane dislocation, and threading edge dislocation, and their locations in the active and JTE region, on the reverse performance of 4H-SiC p-n diodes. It was found that higher leakage current in diodes is associated with basal plane dislocations, while lower breakdown voltage is attributed to screw dislocations. The above influence increases in severity when the dislocation is in the active region than in the JTE region. Furthermore, due to the closed-core nature, the impact of threading edge dislocation on the reverse performance of the p-n diodes is less severe than that of other dislocations although its density is much higher.     

在用制冷压力容器试压工质及其应用技术的研究

压力试验是在用制冷装置压力容器安全监察和检验工作的重点之一,本文在介绍常用制冷剂的热力特性的基础上,分析和探讨了采用替代制冷剂后系统运行参数的变化、压力试验介质的基本选择、容器压力参数变化和不同制冷剂的压力试验以及安全装置的设定等.     

I-V曲线测试仪在线校准方法研究

为解决I-V曲线测试仪在量传溯源方面的技术问题,通过对太阳电池开路电压（Voc）、短路电流（Isc）测量方法和技术的研究与开发,实现了对I-V曲线测试仪Voc,Isc参数的在线测量,从而完成了对I-V曲线测试仪的系统在线校准。研究结果表明,Voc,Isc在线校准的相对示值误差分别为0.45%,0.20%,满足了光伏产业相关设备的量传溯源需求,为该产业健康发展提供了技术支撑。     

The effect of Ca-rich on the electric properties of Ca1+xCu3−xTi4O12 polycrystalline system

Ca_1+xCu_3−xTi₄O₁₂ (x = 0, 0.25, 0.5, 1) ceramics were prepared using the conventional solid-state reaction method. The XRD patterns show that Ca_1+xCu_3−xTi₄O₁₂ compounds are comprised of CaCu₃Ti₄O₁₂ (CCTO) and CaTiO₃ (CTO) phases compared with the traditional CCTO and the content of CTO phase increases with the increase of x. The micrographs demonstrate that the sample for x = 0 has larger grain size 8-10 μm. However, for the samples (x = 0.25, 0.5, 1), the mean grain size decreases markedly with the increase of CTO phase. The measurement for electric properties indicates that the permittivity values decrease with the increase of Ca atoms, but the breakdown electric field E_b and the nonlinear coefficient α values have a behavior reverse to it. The nonlinear coefficient α reaches 28 for x = 1, yet it is only 11.4 for x = 0 in the current range of 1-10 mA. This can be ascribed to the reduction of grain size and the changes in the electric conductivity of main grains and grain boundary with increasing Ca/Cu ratio. Imbalances between Ca and Cu atoms with Ca in excess can favor the non-ohmic properties in detriment to the dielectric property and a suitable Ca/Cu ratio can be selected to adjust the permittivity and I-V nonlinearity, according to different desired device applications.     

An investigation into the parameters affecting the breakdown voltage and inter-particle bonding in the electrical discharge compaction of metal powders

The aim of present investigation is to gain deeper understanding of breakdown behavior and inter-particle bonding by conducting experimental tests. This may lead to improve the state of compaction by relative arrangement of initial parameters to maintain uniform distribution of current density and producing compacts with sufficient mechanical strength. Experimental work was carried out using two different set-ups. The first arrangement was employed to provide steady-state alternating voltage. The effect of column geometry and particle size on breakdown voltage was investigated under this condition. The second set-up, capacitor discharge circuit, was used to provide impulse voltage. Under this condition, the influence of column geometry, particle size, application of axial pressure, evacuation of air, energy input, electrode material and configuration on breakdown voltage was studied. Also, scanning electron microscopy was employed to study the effect of different parameters on inter-particle bonding. The results of experiments conducted on the influence of each of the voltage and capacitance on the compaction properties are also discussed.     

An Experimental Technique for the Analysis of Slug Flows in Pneumatic Pipelines Using Pressure Measurements

An experimental technique has been developed to measure the flow characteristics of slugs in dense phase pneumatic conveying using pressure measurements. This method is based on the unique characteristics of slug flows in pipes, i.e., an axial pressure fluctuation along the pipeline and a pressure difference in the radial direction at the back of a slug. Standard differential pressure transducers were used in this study and the influence of the finite response time of these transducers was considered. Experiments were conducted over a range of gas-solids flow conditions and experimental data were analyzed to describe the behavior of solids slugs through pipes. The calculated slug velocity and length using axial pressure measurements were confirmed by video recordings, and the synthesis between axial and radial pressure signals showed reasonable agreement in flow pattern analysis. This relatively simple measuring technique has been found effective in detecting solids slugs traveling through horizontal pipes and will distinguish various flow regimes. It provides a useful and easily applied tool for system optimizing and benchmarking in industrial applications.     

导热系数测试仪校准中压力影响研究

根据防护热板法导热系数测试仪的原理和特点,通过专门的压力实验测试,研究了多孔绝热材料导热系数参比板在不同温度、压力条件下的厚度变化,提出了实际校准中建议采用的压力设定值,在实际校准工作具有一定的参考价值。