用微电子技术改造转子槽铣床

一、设备状况 B1-195转子槽铣床,是对汽轮发电机转子槽进行加工的大型专用机床,是我厂关键性的生产设备。自1983年以来,其电气系统一直没有大修,元器件老化,故障频繁,发现以下问题: 1.用于工作台进给的直流电动机的调速控制是60年代的可控硅调速装置。调速不稳定,要求低速达10r/min,而实际上只能达到40r/min。     

“百万千瓦级发电机数控转子槽铣床”科技成果通过鉴定

2013年12月19日，中机联在武汉组织专家对武汉华中自控技术发展有限公司完成的“XKH9720型百万千瓦级发电机数控转子槽铣床”科技成果进行了鉴定。该成果是国内首台自主研发制造的满足AP1700发电机转子质量要求的全序数控加工机床。     

修理小型电机的几种适宜方法

1.鼠笼转子断条修理方法（1）铝条与端环之间开裂,可用气焊来修补。（2）个别铝条断裂时,可局部修理。将槽两端风叶锯下,夹住转子,用手摇钻把槽内的断条钻掉,注意不要钻到铁心上,然后在槽内打入一根好的铝条,再将铝条与端环风叶重新焊好。（3）断条较多时,可将转子加热至650～700℃,     

柔性转子的动平衡测试技术

微型涡轮发动机转子的转速一般高达几万至十几万转,常处在超临界转速下工作。这种柔性转子,若不平衡激振力过大,极易影响发动机的正常工作,甚至会引发灾难事故。因此,转子的动平衡被认为是转子运行成败的关键技术。本文介绍一种利用实验室现有设备,使用北京巨业科技开发中心生产的VT9410(A)动平衡仪,对转子进行平衡的方法。 一、柔性转子的动平衡原理和测试技术 对于微型涡轮发动机,在进行常规的刚性转子的动平衡后,虽然已获得了较高的平衡精度,     

旋转机械转子不平衡的现场校正

一、转子不平衡的特征 转子不平衡是具有偏心质量的转子,在旋转时产生一种惯性离心力,它在转子径向平面内的任一方向都会引起一个与转速频率相同的强迫振动。如果在轴承的某一方向上安装测振传感器,它就会收集到这一振动信号,经傅立叶交换,就转换为可识别的频谱。此种信号在时域内的波形为正弦波,在频域内是离散的     

铝电解槽上部结构件吊运重力平衡问题探讨

大型铝电解槽上部金属结构件的吊运过程是槽大修工作的重点和难点,解决好300kA槽上部吊运中的重力平衡问题,提高吊运过程的平稳性、可靠性和安全性,是确保槽大修工作安全有序的重要前提。     

可倾瓦式径向轴承对转子动力学影响分析

可倾瓦式径向轴承是为离心压缩机转子提供支撑的核心部件,也是轴承—转子系统中阻尼的重要来源。轴承—转子系统中阻尼的大小不仅对转子的临界转速产生影响,更直接关系到转子不平衡响应振动峰值的高低。以某轴承—转子系统为研究对象,通过改变轴承支点、包角、预负荷等轴承结构,分析其对转子动力学的影响。     

转子动平衡校正不能忽视正确操作

1993年我车间购进一台上海申克公司的H5U型动平衡机,配有较先进的CAB590电测箱。该机平衡精度为1μm,适用于各种大中型转子的低速动平衡校验。自安装以来已成功地对小到一般离心泵转子,大到气压机,甚至烟机转子进行了平衡校正,取得了良好     

风机转子磨损的检测与修复

依据近年来对用户风机转子磨损的修复经验,根据风机转子的各种磨损现象,归纳转子磨损的检测分析、修复方法和修复检验规则。通过修复,使磨损的转子满足了再次投入使用的要求,并投入工况运行,跟踪观察效果很好。     

刚性转子现场简易快速平衡法

目前,转子的现场平衡方法已有多种,如试加质量周期法,两点法和三点法,相对相位法等。但这些方法都要求有一定的测量振幅或测量相位的仪器,且有些方法开停机次数较多,在现场进行设备维护时,有时不太方便。本文介绍一种现场简易快速平衡方法,该方法仅需一支粉笔、一副量角器和一个已知重量的试重块,开停机次数仅为两次,非常适用于在现场对转子进行简易快速平衡。     

Airport capacity and inefficiency in slot allocation

This paper studies the time slot allocation of flight departures when travelers have a preference for departing on peak times and the number of available peak-time slots is constrained by airport capacities. We show that, compared to public airports, private airports may restrain their supply of peak slots strictly below their capacity levels when they serve airlines that compete to the same destinations. Such an inefficiency takes place in airports that have low per-passenger charges and are not too busy. It does not occur in the absence of competition in destination markets.     

Simulating media platform mergers

The empirical analysis of media platforms economics has often neglected the multi-homing behaviour of advertisers. Assuming away the cross-substitutability and/or complementarity between the advertising slots of different platforms could damage the quality and the robustness of counterfactual analysis. To evaluate the consequence of such an abstraction, we compare the simulation results of hypothetical platform mergers when the demand on the advertising side is derived from a Translog cost model which allows for multi-homing, and when it is approximated by using a simple log-linear inverse demand model that ignores the differentiation among media platforms’ advertising slots. Ignoring the existence of substitutes or complements on the advertising side would result in overpredicting the losses of the viewers’ surplus and in underpredicting the gains in platforms’ revenues.     

陆岸终端井口槽HSE管理实践

冀东南堡油田为实现＂海油陆采＂的需要,采用先进的井口槽布井方式,集批量钻井、油气采集、注水、洗井和修井等功能为一体。主要介绍了南堡油田首条井口槽投用以来,在井口槽内采油的HSE管理实践。     

Business as a Pivotal Actor in the Politics of Training Reform: Insights from the Case of Germany

Often admired by international observers, the German dual training system has come under pressure in recent years because of a persistent lack in training slots for young people. The article addresses the question of how policy makers have reacted to the problems in the training market. Particular attention is paid to the formation of politico‐economic coalitions between state actors, business representatives and unions. On the basis of three case studies of recent reforms (or reform attempts), we identify two types of cross‐class coalitions: a conservative coalition that aims at maintaining the status quo of the firm‐based training regime and a segmentalist coalition promoting the gradual transformation of the system towards a less collective and more firm‐centred variety. In both kinds of politico‐economic coalitions, business actors play a pivotal role. The reason for the privileged position of business in the politics of training reform is, I argue, a politically constructed dependency of the state and unions on the continued co‐operation of business in the provision of training slots. In the conclusion, I discuss the implications of my findings for the debate on the dualization of co‐ordinated market economies.     

24槽、2极三相单层同心式绕组穿线、嵌线工艺

本文结合清晰的绕组展开图,阐明了24槽、2极三相单层同心式绕组穿线、嵌线工艺的原理与方法。     

Foreign and domestic US policies: Spectrum reservations and media balance

This article examines the US opposition to a priori planning of the HF and space satellite spectrum, and ‘orbital slots’. This opposition is then contrasted with the rationale of domestic pre-engineered allocation and allotment plans for television and FM radio. The article then contrasts the US animus towards Third World calls for a ‘balanced’ information flow with the longstanding US commitment to fairness, balance, equal access and diversity. The author suggest that the operation of a foreign-domestic double standard could damage US credibility.     

Effects of asymmetric information on airport congestion management mechanisms

We study and compare three different mechanisms for capacity (slot) allocation in a congested airport when airlines have one-dimensional private information: direct allocation of slots, differentiated tolls and slot auctions. With perfect information, direct allocation is a first best policy which can be implemented through Pigouvian taxes or slot auctions; the mechanisms are equivalent in terms of social welfare. With the introduction of asymmetric information this equivalence is lost: direct allocation is always ex-post inefficient and, in some cases, tolls and subsequent quantity delegation is a better alternative social welfare wise. Auctions may be superior or inferior to tolls. We further show that naïve application of Pigouvian tolls is sub-optimal when imperfect information exists.     

基于定向天线无线自组网的快速随机邻居发现算法

为了减少无线自组网的组网所需时间,提升随机发现算法邻居发现的概率,提出了一种基于定向天线的随机邻居发现算法.根据相控阵天线能够自由切换宽波束和窄波束的特点,发挥宽波束搜索能力强、窄波束传输能力强的优势,使用宽波束和窄波束来进行邻居发现,并结合碰撞重传机制和邻居节点辅助发现机制,对碰撞重传的最优竞争窗口值进行了计算.仿真...     

600MW机组锅炉送风机节能改造效果

宁海电厂600MW机组锅炉送风机由于设计选型时裕量偏大,送风机长期在低效率区运行,浪费了大量的电能。在试验和分析的基础上,对送风机叶轮和电机进行了风机转子、轮毂和叶片等的改造。改造后送风机实际运行效率明显提高,送风机的厂用电率从改造前的0．135％下降到改造后的0．105％,经济效益明显,达到了节能改造的目的。     

组态王与Delphi的DDE通信应用

在污水处理控制系统中,组态王通常用于上位机开发,但在很多情况下,组态王需要与其他应用程序进行数据交换。给出组态王与Delphi进行动态数据交换(DDE)实现实时通信的具体设计方法,从而实现上位机数据处理能力的扩展,解决了单纯通过组态王获取数据途径有限的问题。