ABB接触器（A50-50-11^＊220V）

A-Line接触器采用系统一体化概念,实现接触器与断路器、熔断开关、热过载继电器和电子过载保护继电器等元件在功能和安装上的配合,可构成一体化的电动机起动保护装置,结构紧凑,安装方便,产品系列齐全。     

TSD-10中波发射机去抖动电路的原理分析

TSD-10中波发射机的各种命令是由按键或接触器来传递实现的,其开关机按键、升降功率按键和接触器所用的开关均为机械弹性开关,当机械触点接通、断开时,由于受开关中弹簧力和触点之间反作用力等各种力的影响,会产生抖动,这种抖动产生的电信号会让后级电路发生误动作,从而影响发射机的正常工作,因此必须对这种抖动信号进行滤除。本文对发射机几种抖动电路的原理进行了分析,供大家参考。     

三相交流电机缺相保护器

本保护器电路简单可靠、制作容易、无需复杂调试,一装就成。该保护器已获得国家知识产权局颁发的《实用新型专利证书》专利号:为ZL932096026。电路如图所示。工作原理合上开关QS,按下起动按钮SB2,通过B、C相以及继电器K、热继电器FR、SB1的常闭触点和交流接触器KM线圈构成回路得电串接在主电路中的三个主触点闭合,电动机转动。松开SB2,与SB2并联的交流接触器辅助触点和主触点同时闭合,KM线圈仍然通电,并自锁。要停机时按一下SB1使触点断开,接触器辅助触点和主触点全部断开,电动机切断电源停转。     

如何做好电锅炉主要电器元件的日常维护及故障处理

电器元件是电锅炉运行的主要控制元件。其质量的好坏，直接关系到电锅炉的运行稳定性和运行成本的高低。对电器元件的日常维护和巡视检查，在电锅炉运行中就显得尤其重要。本文就电锅炉常用的断路器、交流接触器、热继电器等电器元件的日常维护及常见故障的处理，提出了切实可行的解决方法。     

基于PLC的三相鼠笼式异步机控制系统设计

本设计为plc控制的三相鼠笼式异步电动机控制系统设计。主电路采用断路器、接触器、热继电器等元件组成,采用继电器、并关及西门子S7200完成控制部分设计。实现对电机的过流及过载保护,并通过PLC编程实现电动机的正反转、星角启动、延时自启动等功能。本设计操作简单,易编程,实用性强。     

降低拉绳开关引起的直流系统接地故障

在发电厂、变电所直流系统中,普遍采用蓄电池组作为直流电源。直流电源为给信号设备、保护、自动装置、事故照明、应急电源及断路器分合闸操作提供直流电源的电源设备。直流系统是一个独立的电源,它不受发电机、厂用电及系统运行方式的影响,并在外部交流电中断的情况下,保证由后备电源—蓄电池继续提供直流电源,所以保证直流系统的稳定运行至关重要。传统的输煤皮带机拉绳开关触点并联到跳闸回路中,回路是由直流电源控制,改进型的拉绳开关回路是在原有的二次回路上先将拉绳开关接到一个带有保险端子排的转接箱内,最后接到皮带机开关柜的交流回路中,并且通过增加断路器及扩展继电器的方法,将二次回路设计成交流、直流交替控制,克服了传统回路由于拉绳开关引起的直流接地故障,也能直观地判断某个拉绳开关故障。     

一种新型的大电流射频接触器介绍

在大功率中波广播发射机中,广泛应用一种新型的大电流射频接触器,通过对刀口部分不同的短路方式,进行不同的开关组合,安全便捷的完成在高频环境中赋予的切换任务。     

智能交流接触器数据采集模块的研究

交流接触器是电力系统和自动化控制系统中不可缺少的量大面广的低压电器.但是传统接触器功能单一、耗电多、噪音大、触头容易烧毁、寿命短.随着科学技术的飞速发展,电力网和其他控制系统和保护电路对交流接触器的性能要求日益提高,希望设计制造出体积小、重量轻、寿命高、精度和可靠性高、节能、可通信、价格合理的交流接触器.本课题的研究具重要的经济意义和社会的应用价值.本文主要介绍了智能接触器数据采集模块的设计,开关量、模拟量信号的采集     

巧用时间继电器

笔者在为XF-2型集卵机而设计的电气仪表线路中,由于巧用时间继电器,达到一举多得的效果,其巧妙之处是: 1.在设计线路时,按一般方法需由交流接触器或通用继电器控制电子泵(为晶体管电磁柱塞泵的简称)与时间继电器,再由时间继电器控制拖动用微电机。由于选用了气膜式JSKI-4型时间继电器,就可以用其一对瞬动常开触点代替交流接触器或通用继电器的常开触点对电子泵和时间继电器本身进行控制,这样就节省了一个环节,如电气仪表原理图所示的JS_2处即是。 2.设计要求在正常情况下,电子泵停止工作的同时延时停止微电机工作;有时可能因某种实际情况,使微电机不能按预先整定的延时时间完成预定的动作,     

电源保护设备

熔丝、电路断路器、继电器、断路开关和浪涌电压保护器可以保护自动化系统、控制系统和设备,维持工厂运行。对比10个新产品,并聆听受访者对选型有何建议。     

基于模糊PID参数自整定的细胞培养箱温度控制算法

针对细胞培养箱温度控制具有非线性、时滞性、易受干扰且难以建立精确的数学模型的特点,传统的PID控制方法对于快速维持系统箱内温度稳定存在一定的局限性。提出了以温度误差和误差变化率为控制输入,培养箱内温度为控制量的模糊PID参数自整定的温度控制算法,实现了对PID参数的实时在线修正。实验表明,该模糊PID参数自整定温度控制算法,温度从26℃上升到目标温度37℃,建立稳态的时间为2890s,温度超调极小。系统温度控制精度为±0.05℃,并在相同型号的细胞培养箱上同样得到验证。在控制稳定性方面获得了比传统PID控制更好的控温效果,稳定快,极小超调,温度控制精度高,能满足细胞培养箱温度控制的要求。     

Hyperbolic regression analysis for kinetics, electrophoresis, ELISA, RIA, Bradford, Lowry, and other applications

Hyperbolic regression analysis is an effective method for fitting experimental data points obtained from a variety of experiments in molecular biology, including enzyme kinetics, agarose gel electrophoresis of DNA fragments, SDS-polyacrylamide gel electrophoresis of proteins, enzyme-linked immunosorbent assays (ELISA), radioimmunoassays (RIA), Bradford protein quantitation assays, Lowry protein assays, and other applications. Hyperbolic regression yields excellent fitted curves without the biases that are introduced by carrying out linear regression on double reciprocal coordinates, and it produces one simple equation, encompassing all the data points, that can be used easily in a pocket calculator to estimate the values of unknown samples from the known standards.     

Louis Kruh,Cryptologist, Editor,Activist

Abstract

The double transposition cipher was considered to be one of the most secure types of manual ciphers. It was extensively used in both World Wars and during the Cold War. In 1999, Otto Leiberich, the former head of the German federal office for information security, suggested that a double transposition challenge be published with specific parameters designed to ensure its security. Such a challenge was published by Klaus Schmeh in 2007. In November 2013, the authors solved the challenge using a ciphertext-only hill climbing attack. They also solved the challenge using a dictionary attack. In this article, they describe both methods, which are based on a “divide-and-conquer” approach. They additionally discuss the impact of their solutions with respect to the general security of the double transposition cipher.     

Pointcuts, advice, refinements, and collaborations: similarities, differences, and synergies

Aspect-oriented programming (AOP) is a novel programming paradigm that aims at modularizing complex software. It embraces several mechanisms including (1) pointcuts and advice as well as (2) refinements and collaborations. Though all these mechanisms deal with crosscutting concerns, i.e., a special class of design and implementation problems that challenge traditional programming paradigms, they do so in different ways. In this article we explore their relationship and their impact on modularity, which is an important prerequisite for reliable and maintainable software. Our exploration helps researchers and practitioners to understand their differences and exposes which mechanism is best used for which problem.     

Texture,contour, shape,and motion

Intrinsic magic calculation exploits constraints arising from physical and imaging processes to derive physical scene parameters from input images. After a brief review of a paradigmatic intrinsic image calculation we turn to a recent result in shape from texture and then to a new result that derives shape and motion from a sequence of patterned inputs. Experimental results are demonstrated for synthetic and natural images.