三峡左岸电站VGS机组推力轴承分析

三峡左岸电站VGS(VOITH-GE-SIEMENS集团)机组推力轴承为小弹簧束支撑结构.小弹簧支撑推力轴承属弹性支撑,安装后不需进行受力调整.本文主要针对VGS水轮发电机组推力轴承运行情况,介绍了VGS水轮发电机组推力轴承的结构、运行及技术改造情况,分析了瓦温偏高的原因,并提出改进建议.     

复合材料瓦推力轴承热弹性动力润滑研究

为了解决蓄能机组复合材料瓦面推力轴承的计算问题,根据流体润滑理论,建立了流体动力润滑数学模型,并对某蓄能机组复合材料瓦推力轴承进行热弹性流体动力润滑计算分析.对比PEEK复合材料瓦和钨金瓦推力轴承表明,PEEK复合材料瓦变形小,瓦温低,可以替代钨金瓦推力轴承.研究成果可以应用于相似结构和材料的推力轴承计算分析.复合材料瓦推力轴承可以应用于蓄能机组中.     

三峡右岸发电机推力轴承热弹流性能分析

对三峡右岸小支柱簇双层瓦推力轴承进行了热弹性流体动力润滑性能有限元分析.采用推力轴承润滑计算的有限元程序,并借助ANSYS软件的热传导和热弹变形分析功能,形成了一套完整的推力轴承热弹流动力润滑性能分析软件.物理模型包括润滑油膜、推力轴承和镜板推力头.对三峡试验推力轴承性能的计算结果和测量结果进行了对比分析,计算结果和实...     

新型卧式液体静压轴承在斜击式模型水轮机上的应用

本文介绍了一种新型的卧式液体静压轴承在斜击式模型水轮机上的应用。鉴于斜击式水轮机具有轴向水推力的特点,在这套卧式液体静压轴承中采用了双斜面背靠背的双止推结构。本文叙述了这种双套轴承的工作原理、结构特点、设计计算方法、调试及运行情况。     

水轮发电机组推力轴承技术的发展

本文介绍了水轮发电机组推力轴承瓦面材料、支撑结构和循环冷却系统,推力轴承设计技术和试验技术及推力轴承的发展.     

立式电机推力轴承的发展现状

介绍了国外立式电机轴承的发展现状,并论述了立式电机推力轴承的特点.在对轴承工作特性、支承结构和轴瓦的几何形状重点分析的基础上,比较了不同轴承支承结构形式和轴瓦几何形状对推力轴承的影响,继而结合工程应用的实际情况,提出较为合理的选择方案.最后针对立式电机推力轴承在应用过程中的常见故障,提出可行的解决办法.     

弹簧束支承的塑料瓦推力轴承

本文通过弹簧束支承结构塑料瓦推力轴承在推力台上的试验结果,说明了弹簧束支承结构的塑料瓦推力轴承具有油膜温升低,油膜厚度均匀,因而压力峰值小,承载能力大的特点,在包括抽水蓄能机组在内的中、大型机组推力轴承中有着广阔的应用前景。     

水轮发电机弹性金属塑料瓦推力轴承瓦面形状

本文介绍了水轮发电机弹性金属塑料瓦推力轴承的变形分析和瓦面形状的设计方法.利用结构有限元程序对各种支承结构的推力轴承和镜板推力头进行三维热弹变形分析,真正实现了对推力轴承的热弹流动力润滑性能分析.瓦面形状设计合理、准确.其结果对弹性金属塑料瓦的设计具有指导意义.     

水轮发电机推力轴承支承结构性能的研究

本文通过在我公司1000t 推力轴承试验台上进行的四种推力轴承支承结构钨金瓦的试验结果的分析与对比,论述了支承结构对水轮发电机推力轴承性能的影响。双托盘支承及弹簧束多点支承结构由于能部分抵消推力轴承运行时产生的力变形与热变形,瓦面形状较佳,因而具有较大的承载能力,很适合三峡机组推力轴承。本文在分析对比时采用无量纲轴承参数,以期得到较为客观的对比结果。     

大型抽水蓄能机组推力轴承运行特点研究

对大型蓄能机组推力轴承进行全模拟试验,从结构参数设计、冷却润滑方式、转速区间三方面,分析大型抽水蓄能机组推力轴承运行特点.弹性油箱、弹簧簇均是较好的支撑方式,轴承设计中应根据工况和轴瓦的结构参数确定是否进行轴承瓦面的型面设计及结构参数优化;推力轴承油槽液面最少应比轴承摩擦面高25 mm以上;在某个转速区间内,推力轴承瓦...     

钢管混凝土柱应用于大偏心受压框架柱的设计

结合工程实例，介绍了钢管砼柱在多层框架建筑中的应用，以及钢管砼柱和两种特殊节点的设计。     

大功率潜油电机的设计及模拟实验样机的制造

针对潜油电机的特殊结构,研究其定转子分段的特点对电机设计及性能的影响.通过求解三维磁场得出隔磁段所引起的漏抗,对转子冲片巧妙设计以起到斜槽的作用,在电机局部的设计计算上采用了辛普森算法和分层算法等方法,改进了潜油电机的设计方法并在此基础上设计制造了模拟实验样机,分析实验结果表明改进后的设计方法正确可行,对于提高此类电机的设计精度具有重要意义.     

Magnetic field analysis of a squirrel cage induction motor considering rotor skew and higher harmonics in the secondary current

This paper describes a method to analyze harmonic magnetic fields of squirrel cage induction motors considering rotor skew and higher harmonics in the secondary current. The proposed method is based on a two‐dimensional finite element method. The rotor skew structure is expressed by multiple 2D finite element mesh models, produced in suitable axial positions, and the magnetic field in each mesh model is calculated by the revised secondary current taking into account the skew effect. The secondary currents, magnetic flux densities, and electromotive forces are calculated by the proposed method. Then the differences between a skewed rotor and a nonskewed rotor are discussed. From the comparison between the calculated and the experimental results, the proposed method is shown to be appropriate and useful for quantitative estimation of harmonic components of induction motors. © 1999 Scripta Technica, Electr Eng Jpn, 129(2): 98–109, 1999     

福清核电站常规岛发电机定子吊装方案

介绍了福清核电站常规岛发电机定子吊装方案。该方案使用液压提升装置及配套吊装构架,建立了吊装构架的有限元分析模型进行力学分析。实际应用表明,吊装构架结构紧凑、安全可靠;支柱采用桁架柱与柱脚箱结构,降低了对基础的要求; 新型顶推滑移方式平稳、无冲击,安全可靠; 钢索式液压提升装置具有起重能力大、结构紧凑和自动闭锁等优点,非常适合发电机定子等设备的吊装工作。     

高内压盾构隧洞原位试验及衬砌变形行为研究

针对城市地下高内压盾构输水隧洞工程,提出一种“外衬管片-中衬自密实混凝土(self compacting concrete,SCC)-内衬钢管”分离式衬砌结构,立足珠江三角洲水资源配置工程试验段,开展衬砌结构原位试验,探索该结构的变形行为.采用柔性囊体实现洞内高内压的可控有序加压模拟,并使用光纤光栅及分布式光缆测试技术...     

Iron Losses in Cable Supports and Members of Tunnels Adjacent to Large Power Transmission Cables

Iron losses in cable supports and members of tunnels in large power transmission were measured and analyzed by arranging cables in various configurations in tunnels of actual size and about 10 m long in order to study iron losses which come from cable supports and members of tunnels adjacent to large power transmission cables installed in tunnels. Cable supports used in the study were typically made of square hollow steel pipe and L-bar. A box culvert tunnel, a steel segment tunnel and a reinforced concrete segment tunnel, which are widely used as tunnels for large power transmission cables, were prepared for the measurement. Theoretical expressions for qualitatively evaluating iron losses in various cable supports and members of tunnels were derived, and their validity was confirmed by experiments.     

Permanent Magnet Motor Torsional Resonance Noise Reduction by Rotor Skew Phase Adjustment

Hybrid Vehicles (HEVs) and Electric Vehicles (EVs) improve drive efficiency and reduce CO₂ emissions by regenerative braking and operating the engine under optimum conditions. It is desirable to decrease the motor size and increase the maximum torque to minimize driving units. For these purposes, motors employing permanent magnets are now commonly used. The motor driving systems of HEVs and EVs must operate over variable speed ranges of up to 1:5. Over this large range, smooth, silent operation is desirable and important. The skew method is often adopted to ensure a smooth start and stop and silent operation by reducing torque ripple. However, this method possibly causes noise and motor vibration. This paper describes the mechanism of torsional resonance noise and vibrations arising from the skew method and a countermeasure to decrease them by optimizing the skew phase distribution on the rotating axis.     

计算三相异步电动机转子斜槽度

三相异步电动机的振动、噪声一直是电机设计中重点关注的问题之一,其中铸铝转子利用斜槽来削弱齿谐波对电磁转矩和电流的影响是较常用的方法,但斜槽度的确定以往大多数都是依靠经验和制作样机来完成的。使用Ansoft Maxwell等电磁场有限元分析软件的瞬态分析功能,计算出电机的电磁转矩和绕组电流波形而得出谐波频率,就能计算出所需的转子斜槽度。     

椭圆余弦内波作用下沿海电厂卸煤码头墩柱受力分析

将沿海电厂卸煤码头简化为只有2排4个墩柱,模拟了沿海椭圆余弦内波的生成,并且得到了不同周期和波高下椭圆余弦内波的波浪形态.在特定的周期和波高条件下进行了三维椭圆余弦内波作用于码头墩柱的数值模拟,分析了墩柱上受到的惯性力和粘性力的变化趋势,得出墩柱上受到的波浪力呈现周期性变化并且第2排墩柱受力小于第1排的受力.     

Investigation on a choice of stator slot skew angle in brushless PM machines

The paper investigates the effects of stator slot skewing in a permanent magnet brushless DC motor. A simple analytic formula for calculation of the best angle of stack skew, which leads to nearly total reduction of the cogging torque, is developed. The skew angle obtained from this formula is different to that used by the designers of PM brushless motors. The analysis is carried out for a fractional horsepower brushless permanent magnet motor with the surface-mounted magnets using a time-stepping, multi mesh-slice finite element model, to assess the impact of this change. The steady-state characteristics and core losses are analyzed quantitatively using the elaborated numerical model. It is shown that smaller skew angles obtained from the formula lead to noticeable rise in motor overall efficiency and decrease of the core loss. The possibility of accomplishment of the desired effect of skew in a real machine is also a subject of discussion.