500kV电容式电压互感器电压异常分析及处理

介绍电容式电压互感器的工作原理、结构及故障情况,结合CVT介损电容量测试数据、一次电压监测数据、角差比差试验数据,分析某变电站500kV电容式电压互感器电压异常的原因,并提出处理措施和建议。     

35kV母线CVT高压侧熔断器异常爆裂原因及解决方案研究

为了解决甘肃天水电网35kV侧母线CVT在电力电容器合闸时,其高压侧熔断器发生异常爆裂的事故,通过对电力电容器合闸过电压的Matlab仿真分析,得到了引起该事故的原因.电力电容器合闸过程产生的过电压激发CVT中间变压器铁芯饱和,进而引发CVT内部非线性电感和电容铁磁谐振,产生谐振过电流,使熔断器发生爆裂.针对这一原因,文中从限制电力电容器合闸过电压和对CVT消谐两个方面提出了解决方案.仿真验证这些方案具有可行性.     

Molecular structures of traction fluids in relation to traction properties

In order to develop excellent traction fluids, guidelines for molecular design were studied through analyzing correlation between molecular structures and traction properties of traction fluids quantitatively. Some results among various simple compounds as model compounds of traction fluids and among various traction fluids were described in this article. This revised version was published online in June 2006 with corrections to the Cover Date.     

大速比多项作业车辆采用一种牵引弧锥环轮式无级变速传动和牵引行星传动的变速箱

采用一牵引无级变速传动和一行星牵引定速比传动的一种新型变速箱已经设计、研制与试验。本文将以功率流概念和新部件结构两方面来描述这种变速箱的设计。把这种无级变速传动和行星传动综合成一体，可以据此由三个功率流实现总速比２０∶１以上的大无级变速范围。不加其他设备可实现空档与倒档。该变速箱已装于０．５ｔ轻型货车做大速比车辆变速箱有关试验。     

摩托车速控无级变速器设计

根据踏板式摩托车无级变速器使用过程中存在的问题,通过改变控制变速比的方法,使之适应摩托车的各种工况。     

恒功率恒滑动率行星锥盘无级变速器的设计构想

在分析通用行星锥盘无级变速器缺陷的基础上,提出了针对文献[1]所述的恒功率行星锥盘无级变速器的锥盘形状进行改进的设想,以改善主要工作件的受力状况,降低机器滑动率,并最终实现恒功率恒滑动率传动的目的。     

考虑动力系功率损失和CVT响应滞后集成发动机-CVT控制的性能

本文考虑由于CVT速比变化引起动力系功率损失和惯性转矩推荐了一种集成发动机一无级变速器(CVT)控制算法。此外还提出了减少CVT速比响应滞后对驱动转矩影响的补偿算法。实验结果表明，最佳发动机速度补偿算法给出最佳发动机工作点在最佳工作线附近。当加速度响应接近相等时和最佳转矩补偿比较。建议把集成发动机-CVT控制算法的特点和传统CVT相比较，加速时采用集成控制来实现在最佳工作线上找到最佳发动机工作点。     

汽车无级自动变速器(CVT)液压控制系统综述

简述了CVT的传动机理，介绍了CVT液压控制系统的种类、组成、工作原理及研究现状。     

Preparation of w–cu nano-composite powders with high copper content using a chemical co-deposition technique

A novel chemical co-precipitation was used to produce W-70%Cu nanocomposite powders with coating structure. The precursors consisting of CuC₂O₄·xH₂O and WO₃·2H₂O were first synthesized using copper nitrate, ammonium metatungstate(AMT) and oxalic acid as the raw materials at 80?°C for 1.5?h when the concentrations of the reactants were 0.8?mol/L and the hydrogen ion concentration was 1.2?mol/L. The precursors were calcined to produce the powders with different phase components and microstructure at various temperatures. The CuWO₄ and CuO nano-powders were obtained at 300?°C, which is colder than the traditional reaction temperature (1000?°C) of CuO?+?WO₃ = CuWO₄. However, the cubic Cu₂O and Cu₂WO₄ could be formed when the calcining temperature was 600?°C. The hydrogen reduction results show that the calcined powder is reduced to obtain W-Cu composite powder at 750?°C and 800?°C. In reduction process, volatile WO₂(OH)₂ through chemical vapor transport(CVT) continuously spreads to the copper surface and is reduced to form W and the coated particle is eventually formed. This particle is Cu particle coated by W phase and the interface between W and Cu phases is semi-coherent. It is found that the average particle size of the reduced powder is 30–50?nm observed by TEM images.     

Zero-Max型无级变速器传动机构的振动分析

采用有限元法对Zero-Max型无级变速器主传动机构的振动特性及受力危险部位进行了分析。主传动机构是由2个平面四杆机构串联而成的平面六杆机构,通过对各构件的模态进行模态叠加和模态综合,得到传动机构的固有频率和振型。从模态分析的结果可知,传动机构各构件危险部位多发生在靠近两级串联机构相连处附近,其失效多发生在这些部位。