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关键词： 交流开关和控制开关   交流电流   交流电动机   特性曲线   电路   图示   电动机   电气工程   熔断体   熔断器   高电压   高压电器   高压熔断器   电动机保护   电机起动   电机   过流断路器   过载保护装置   保护设备   短路电流   规范(验收)   规范   启动电流   开关设备   测试  

标准号: BS EN 60644-2009

摘要： This standard applies primarily to fuse-links used with motors started direct-on-line on alternating current systems of 50 Hz and 60 *** When motors are used with assisted starting this specification can also be applied but particular attention should be paid to the selection of the rated current of the fuse-link (see 8.1) and the manufacturer of the fuse-link should preferably be ***-links according to this specification are intended to withstand normal service conditionsand motor starting pulses. They should comply with the requirements of IEC *** purpose of this standard is to standardize time-current characteristics, to formulate pulsewithstand requirements regarding testing and to give guidance regarding the selection of fuselinksintended to be used with motors.

关键词： 断路容量   定义   设计   拆分范围   电气工程   电气设备   熔断体   熔断器   冲击设备   指示装置   低电压   低压熔断器   使用条件   特性   保护(装置)   保护设备   额定电压   半导体器件   半导体工程   半导体保险丝   规范(验收)   试验   类型   电压源  

标准号: BS EN 60269-4-2009+A1-2012

关键词： 断路容量   定义   设计   拆分范围   电气工程   电气设备   熔断体   熔断器   冲击设备   指示设备   低电压   低压熔断器   使用条件   性能   保护(装置)   保护设备   额定电压   半导体器件   半导体工程   半导体保险丝   规范(验收)   测试   类型  

标准号: BS EN 60269-4-2009

摘要： These supplementary requirements apply to fuse-links for application in equipment containingsemiconductor devices for circuits of nominal voltages up to 1 000 V a.c. or 1 500 V d.c. andalso, in so far as they are applicable, for circuits of higher nominal *** 1 Such fuse-Iinks are commonly referred to as “semiconductor fuse-links”.NOTE 2 In most cases, a part of the associated equipment serves the purpose of a fuse-base. Owing to the great variety of equipment, no general rules can be given; the suitability of the associated equipment to serve as a fusebase should be subject to agreement between the manufacturer and the user. However, if separate fuse-bases or fuse-holders are used, they should comply with the appropriate requirements of IEC *** object of these supplementary requirements is to establish the characteristics of semiconductor fuse-links in such a way that they can be replaced by other fuse-links having the same characteristics, provided that their dimensions are identical. For this purpose, this standard refers in particular toa) the following characteristics of fuses:1) their rated values;2) their temperature rises in normal service;3) their power dissipation;4) their time-current characteristics;5) their breaking capacity;6) their cut-off current characteristics and their I2t characteristics;7) their arc voltage characteristics;b) type tests for verification of the characteristics of fuses;c) the markings on fuses;d) availability and presentation of technical data (see Annex B).

关键词： 辅助装置   铜导线   定义   接地导线   导电体   电气工程   熔断器   低电压   低压设备   低压开关设备   处理   性能   额定值   安全性要求   规范(验收)   开关   开关装置   接线板   测试  

标准号: BS EN 60947-7-3-2009

摘要： This part of IEC 60947 applies to fuse terminal blocks with screw-type or screwless-typeclamping units for the connection of rigid (solid or stranded) or flexible copper conductors forthe reception of cartridge fuse-links in accordance with IEC 60127-2, intended primarily for industrial or similar use in circuits not exceeding 1 000 V a.c., up to 1 000 Hz or 1 500 V d.c., and having a maximum short-circuit breaking capacity of 1 500 *** are intended for installation in electrical equipment with enclosures which surround thefuse terminal blocks to such an extent that they are accessible only with the aid of a *** certain applications, for example in control circuits, the fuse terminal blocks may bedesigned exclusively for short-circuit *** This standard may be used as a guide for fuse terminal blocks for the reception of special cartridge fuselinkswhich do not meet the requirements of IEC *** object of this standard is to specify safety requirements and test methods for the mechanical, electrical and thermal characteristics of fuse terminal blocks, to ensure the compatibility between terminal blocks and standardized *** standard may be used as a guide for? fuse terminal blocks requiring the fixing of special devices to the conductors, for examplequick connect terminations or wrapped connections, etc.;? fuse terminal blocks providing direct contact to the conductors by means of edges or pointspenetrating the insulation, for example insulation displacement connections, *** applicable in this standard, the term “clamping unit” has been used instead of the term“terminal”. This is taken into account in case of reference to IEC 60947-1.

关键词： 音频功率放大电路   OCL电路   仿真分析   音频功率放大器   基本电路   耦合电容   电路实验   定量估算  

摘要： 引言 OCL电路是高保真音频功率放大器的基本电路之一，它去除了输出级与扬声器之间的耦合电容，使扬声器与输出级电路直接相连，因此电路的频带进一步向低端扩展（接近于零），保真度更高，使用更普遍。与此同时在设计和制作中也给我们带来了一些缺点，如修改某个元件的参数就会影响前后级的工作点，需要重新计算或调整其他元件的参数值等。因此传统的方法是以定量估算和电路实验为基础，工作量较大。

关键词： 电磁式交流接触器   动态特性分析   labVIEW   振动和噪声   软件系统   系统动态特性   计算软件   相关产品  

摘要： XMCO—188型交流接触器是一种空调控制专用接触器，如何减小其工作中的振动和噪声是一个值得商榷的问题。本文采用labVIEW软件系统，建立XMCO-188型交流接触器吸合过程与吸持阶段动态特性计算软件，通过动态仿真计算结果，提出减少产品噪声的措施和建议。该软件系统人机界面友好、直观、方便，便于系统的维护和功能扩展，也可方便的应用于其他型号电磁式交流接触器电磁系统动态特性的计算和分析中。为相关产品电磁机构的进一步优化奠定基础，这种基于虚拟仪器的设计方案具有一定的实用价值。

关键词： 交流接触器   化工生产   晃电   应用   电网电压   电压闪变   电压暂降   额定电压  

摘要： 1晃电现象及其影响 电网发生电压暂降或电压闪变，俗称晃电。现象为：电网电压在0．01S～1min内下降到额定电压的10％-90％，然后又恢复到正常水平。

关键词： 并联电容器组   熔断器   群爆   谐波   电抗器  

摘要： 以某220kV变电站发生的电容器组熔断器群爆故障为实例,据其呈现的特征,提出故障分析的方法以及整改方案,为避免电容器组熔断器"群爆"的现象再次发生提供借鉴。

关键词： 555定时器   单稳态触发器   多谐振荡器   工作模式  

摘要： 555定时器是一种中规模集成电路,只要在外部配上适当阻容元件,就可以方便地构成各种脉冲产生和整形电路,例如多谐振荡器、施密特触发器和单稳态触发器等。主要分析555定时器的电路结构、逻辑功能及工作模式,并介绍由555定时器构成的各种典型电路的组成、工作原理、元器件选择等,以供电子爱好者设计时作为参考。

关键词： 接触器   全速   维护费用  

摘要： 本文通过对原来设计四台SSC-F5060-1600KW型内反馈调速装置,对于其柜内交流接触器在实际运行中出现的不稳定状态,大胆地进行了共计12台的交流接触器的技术改造,既保证了热电厂的安全运行又确保了锅炉正常运行的炉堂负压。