XFD-7A型低频信号发生器故障分析排除一例

<正> XFD—7A型低频信号发生器是一种性能比较稳定电子管型的RC信号发生器,其功率输出级抗短路电流冲击性远优于晶体管低频信号发生器,晶体管低频信号发生器虽在功率输出级上设有短路电流保护装置,但在学生的实验中因短路造成大功率输出管损坏的现象仍时有发生,这也是电子管型低频信号发生器在有些实验室和一些部门中至今仍被使用的原因吧。     

突发短路对110kV主变压器损坏分析研究

110 kV及以上主变压器因外部短路引起的损坏的原因是多方面的,文中对一起典型的近距离突发短路造成两台变压器严重损坏进行详细分析,并结合相关检查试验项目和要求,对变压器近距离出口短路损坏事故的过程、检查试验情况和分析处理进行叙述,介绍了变压器经受出口短路损坏后的现场判别和修复方案,提出针对性的防范措施,为提高电网和设备安全、稳定、健康运行提供参考和借鉴.     

捷克W160HA镗床进给系统

W160HA镗床是一台捷克进口的机床，使用中经常出现机床送电主回路保险熔断的现象。为此进行了系统的测试与分析，并经过适一排除，发现一只二极管损坏，更换二极管后，故障排除。     

RM1-20-5中等延时熔断器

中等延时熔断器在过电流保护方面有着特殊的功能，具有耐脉冲电流冲击，过电流时又能较快熔断的特点，因而能较好地保护电子设备与仪器的安全，RM1-20-5型中等延时熔断器采用高熔点金融与低熔点金属所组成的复合熔丝结构而达到中等延时效果。作为电路中过电流和短路电流保护器，它可被广泛用于各种电子仪器与设备中。     

设备基础损坏的快速处理

设备基础是设备安全运行的先决条件,基础在设备的长期运行中也同样受到疲劳损坏或意外损坏,如不及时处理势必酿成事故.设备基础一般都是钢筋混凝土结构,如重新制作费工费时影响生产.我厂在基础损坏时采用了一些快速处理法,收到了较好的效果.基础长期受冲击载荷的影响,达到疲劳的极限属于正常损坏,一般能做到有计划的修整;另一种事故性的属于无法预见的损坏.我厂的事故损坏一般有:基础底层地质结构的变化造成基础下沉或整体基础移动;基础遭受剪切力过大,造成地脚螺栓断裂;基础施工在二次灌浆时与母基础结合不牢,造成松动.现介绍两起快速修复的实例:1.二次灌浆与母基础脱离或基础中间因受超极限剪切力造成断裂的快速处理.     

基于LabVIEW软件平台的同步发电机短路电流分析与研究

运用一套电机过渡过程微机触发装置,在精确控制短路合闸角的情况下,实现发电机端口的短路,然后通过数据采集器实时采集短路电流信号,并在以LabVIEW为开发平台的可视化软件界面上显示和存储整个短路瞬态过程电流波形,并通过与Madab仿真波形进行了对比分析,总结其短路电流的变化规律.     

电子成果信息

计算机FL系列防雷器 计算机FL系列防雷器是专门为计算机、计算机网络和通信设备防雷电袭击而研制的。雷电是当前危害计算机、汁算机网络和计算机通信设备的一个不可忽视的自然灾害,在全国各地都有因雷电损坏计算机、计算刚络和通信设备的现象,为此研制出计算     

机电信息

自复保险丝将淘汰熔断器 所有的电子设备几乎都离不开保险丝，传统的保险丝又称熔断器。当电子设备由于局部故障引发电流剧增，保险丝温度升高以致合金丝熔化切断供电，从而保护了整个设备，这就是过流保护． 传统的保险丝仅能使用一次，熔断后要在设备检修后更换新的。但是并非每次保险丝的熔断都是设备故障引发的。就是电子设备在正常启动或插拔电源肘，也有可能产生浪涌电流（瞬间大电流）导致保险丝烧毁，目前一种被称作自复保险丝的产品正在逐渐被电子仪器及设备的制造企业采用。自复保睑丝工作原理很简单，实质上是一个热敏电阻。该器…     

电子成果信息

计算机 FL 系列防雷器计算机 FL 系列防雷器是专门为计算机、计算机网络和通信设备防雷电袭击而研制的。雷电是当前危害计算机、计算机网络和计算机通信设备的一个不可忽视的自然灾害,在全国各地都有因雷电损坏计算机、计算网络和通信设备的现象,为此研制出计算机防雷装置。     

均流冗余技术在功率驱动中的应用

选择了一种“恒流”驱动电路，采用并联冗余，在不增加外部控制电路的情况下，能确保各并联支路的电流自动平均分配，使均流和冗余技术融为一体。当其中一路出现过载、短路时．热熔保险迅速熔断，使这一路断开冗余组件，其余支路又自动均流。提高了系统的可靠性。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

基于多目标非支配解提取法的电力系统无功优化

针对传统的电力系统多目标粒子群优化算法采用权重系数法将多目标转化为单目标,从而忽视了各目标函数间的竞争关系这一问题,提出将非支配解提取法运用到电力系统多目标无功优化中,并设定了一套提取规则,以电力系统中的有功网损、电压偏差和电压稳定裕度为目标,使目标在充分竞争的情况下得出Pareto最优解,利用IEEE-14节点系统对多目标非支配解提取法的电力系统无功优化进行了仿真测试。研究结果表明,该算法一次运行可以得出多组非支配解,既有偏向单个目标的解也有兼顾所有目标的解,克服了权重系数法的盲目性和单一性,可使电力决策者根据实际问题选择最优解,具有较好的灵活性与多样性。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.