Motion of a rotor at an elastically anchored stator

A universal multiparametric model of a Jeffcott rotor is presented. The model takes account of stator jamming and vibration, rotor slip at the stator, and noncoaxiality of the rotor and stator. The proposed model is used to determine typical trajectories and motion of the rotor and stator and also to identify the critical values of their noncoaxiality and mutual friction at which the vibrational characteristics of the rotor-stator system sharply deteriorate.     

Analysis of rolling with slip of flexible rotor inside stator

The interaction of a rotor with a stator without separation is considered during their plane-parallel motion and under assumption of constant rotor speed. In contrast to known papers devoted to the problem of the possibility of rolling in the rotor system, it is shown that the retrograde precession frequency is always lower than the inherent one, which corresponds to a zero-clearance flexible–mobile stator system.     

外转子电动机定子轴承室加工工艺研究

针对外转子电动机定子轴承室加工工艺的问题,提出了一种双头车的方法.目前市场上现有的设备,外转子电动机定子两个轴承室的加工不能一次装夹完成.而两次装夹加工误差很大,两个轴承室同轴度很差,无法满足设计需求.因此,研究生产了一种专用双端车床.经过生产实践证明:所研究的双头车床,能有效解决上述问题.     

主回凸轮机构中回凸轮运动规律的确定

主回凸轮机构在泵送机构中应用广泛。利用运动传递的连续性，分析了主回凸轮机构中回凸轮与主凸轮之间的运动关系，循序渐进地找到了回凸轮的运动规律，为下一步回凸轮轮廓曲线的确定奠定了基础。     

电机冲片冲剪工艺与模具结构的改进

以兰州电机有限责任公司中型交流调速电机定,转子冲片为例,结合企业实际,吸收国外同类产品加工工艺的先进经验,对中型电机冲片冲剪工艺的合理性与模具结构提出了改进意见。     

Diagnostics of breaks of rotor winding bars in electric motors based on stator current analysis

The relevant problem of testing the integrity of rotor winding bars in an electric motor is considered. The existing methods for revealing bar breaks are evaluated and an alternative method based on the stator current analysis is proposed.     

Reliability analysis of a nonlinear rotor/stator contact system in the presence of aleatory and epistemic uncertainty

On the basis of an overview of the global responses of a nonlinear Jeffcott rotor/stator contact model, the system reliability was evaluated subject to mixed aleatory-epistemic uncertainty. We used a likelihood-based approach for reliability modeling and analysis. In the context of uncertainty quantification, some advanced Bayesian techniques were adopted to reduce the computation cost in traditional Monte Carlo method. The parameters’ effects on reliability were studied, incorporating both rotor physical background and inherent uncertain factors. This framework could be applied in the field of industrial manufacturing & mounting, risk assessment, product maintaining and benefit rotary machines from design phase to operation stage.     

预变形对多层钢板支撑转子运动稳定性的影响

多层波纹钢板阻尼器支撑转子系统是利用干摩擦作用实现阻尼减振.阻尼器装配时的预压缩变形影响转子的运动稳定性.文中基于李雅普诺夫线性化理论对转子系统的运动稳定性进行研究,得出系统平凡解的稳定条件,并给出应用实例.结果表明,根据预变形处的迟滞回线计算能判断转子系统的运动稳定性.     

Design and determination of stator geometry for axial flux permanent magnet free rod rotor synchronous motor

During designing a new axial flux permanent magnet free rod rotor synchronous motor, it is important to know before hand in which phase the largest angular velocity can occur, what is the ways to reduce the power consumption, how to achieve to increase or decrease the rotation speed by changing the core geometry. Therefore, presenting these preliminary information that are necessary for the design of a free rod rotor synchronous motor to the researchers is the aim of this work. In this respect, this study presents the design and geometrical dimensions of the stator for a new synchronous motor which is an axial flux permanent magnet free rod machine with three, four, five and six phases. This type of motors are an innovative approach especially for the applications used in industrial stirrers. Each type of stator is designed such that it has an appropriate number of phases. The rotating magnetic field over the stator is established by a PIC based microcontroller feeding the interface circuit to the stator wounds. The maximum angular speeds of bar magnet rotors with four different lengths and masses are calculated theoretically and determined experimentally. In addition, the effects of the distance between the rotor and stator, the angular speed of the rotor within the limits of the operation, and the volume of the liquid to be stirred to the power applied are investigated. Furthermore, the effects of the lengths and angular speeds of the bar magnet rotors to the distance between the rotor and stator are determined. In the light of the information obtained and taking into account the power used, the most appropriate parameters and variables such as the stator geometry changing with the phase used, the length of rotor, the distance between the rotor and stator and the angular speeds of rotor are determined.     

Estimation of frequency components in stator current for the detection of broken rotor bars in induction machines

The limitation of data window length in induction machine broken rotor bar diagnostics is a real challenge in practice. Sideband frequencies which are used as broken rotor bar indicators are very close to the fundamental frequency and have low magnitude. Traditional spectral analysis approach such as Discrete Fourier Transform (DFT) can be inaccurate in these conditions due to its inherent drawbacks such as the requirement of long data window for high resolution and the side lobe leakage in frequency domain. In this paper, a high-resolution spectral analysis technique, Prony Analysis (PA), is proposed for broken rotor bar detection in induction machines. The method is described and demonstrated in detail, validated by experimental data, and compared with DFT. Results clearly indicate the advantages of PA over DFT in terms of maintaining a high resolution with a much shorter window and a better frequency estimate accuracy with the same window length.     

鼠笼电机转子断条故障的定子电流信号平方解调分析诊断方法

受基频频谱泄露影响,经典MCSA方法诊断鼠笼电机转子断条故障时的诊断能力严重依赖于电机负载大小。针对这一问题,提出了基于定子电流信号平方解调制分析诊断方法。首先采用硬件方式对定子电流信号作基于平方解调制的信号预处理,以此消除制约诊断能力的基频频谱泄露,继而对解调后的信号作快速傅里叶变换,然后根据频谱中是否存在特征频率成分判断转子断条故障发生与否。在3 k W电机实验平台上对所提出的方法进行实验验证。实验结果表明,即使鼠笼电机在轻载或空载条件下运行时所提出的方法仍然能够诊断出转子断条故障,从而有效提高了诊断能力。     

散斑运动模糊复原的直线电机动子位置检测

图像测量技术具有非接触性、抗干扰性等优点被越来越多地应用到双次级永磁直线电机动子位置检测中。针对图像采集过程中所产生的图像模糊问题,提出了一种精确辨识运动模糊参数的方法,实现了直线电机动子位置的精确测量。采用数字散斑图像作为原始拍摄面,通过相机获得包含动子位置信息的序列运动模糊图像。利用奇异值分解对运动模糊图像进行去噪重构预处理,降低噪声对运动模糊参数辨识精度的影响。求取预处理后图像的倒谱图,通过主成分分析找到倒谱图二值化后亮线的主矢量方向即为模糊方向;同时作出倒谱三维图,利用其负峰值中两个最小值坐标求出模糊长度。根据计算的模糊参数值复原模糊散斑图像,再利用图像亚像素测量方法获得动子位置。实验结果表明:本文算法的计算耗时比Radon算法缩短了5倍多,不同位移下的平均绝对误差仅为0.084 7mm,满足直线电机动子位置检测的实时性和高精度要求。     

Measuring the total pressure in the relative motion of the flux behind a compressor rotor

A nontraditional method is proposed for measuring the total pressure behind the compressor rotor in relative motion of the gas flux. The operation of a rotary probe is considered. The flow pattern at the exit from the rotor’s blade channel is determined.     

结构物滑移装船平衡控制系统的研究

在对驳船受力进行了系统分析的基础上,将自动测量技术和软件集成技术应用到驳船控制,通过调载水量计算模型和稳性控制模型由程序自动判断压载水舱调节水量的大小,进行水位的调节,并对滑移装船的位移进行实时监测,提高了滑移装船的安全性、可靠性和自动化程度.系统以工控机为控制系统的核心,采用RS485网络进行通讯,由弦振式应变测量系统、潮位传感器、激光测距仪等组成数据采集系统.开发了平衡控制系统软件,建立了系统设备、驳船和大型结构物的信息数据库,并开发了检测控制模块、通讯模块和数据处理模块.进行了实验仿真,通过比较结构物滑移装船在不同工况下的计算数据,对平衡控制系统及其稳性控制进行了验证.     

Slipping thrust bearings with initially parallel surfaces in orbital motion of a rotor

Tests of slipping thrust bearings with initially parallel surfaces in orbital rotor motion are conducted on a test bench simulating the kinematics and dynamics of a spiral compressor. On the basis of tests of seven transmission designs, recommendations are made regarding the best material to use.     

螺杆泵漏失机理研究

讨论了腔室内压力、压差和液压作用对螺杆泵橡胶衬套的影响,提出一种新的解释螺杆泵漏失的机理。结果表明:腔室内压力会使橡胶衬套产生压缩变形,导致漏失;压差会使橡胶从高压区向低压区挤动,在一定范围内,反而增强了密封性能;腔室液压力对转子产生的力和力矩会导致转子产生一定的偏移,这也会间接产生橡胶衬套的变形,从而导致漏失。螺杆泵是在上述三者的共同作用下产生漏失的。同时提出一种改进方法,还比较了等壁厚螺杆泵和常规螺杆泵的密封性能。     

Measurement of radial expansion and tumbling motion of a high-speed rotor using an optical sensor system

In order to investigate the load capacity and the strength properties of high-speed rotors, dynamic deformation and vibration measurements are of importance, in particular at lightweight composite devices which cannot be simulated reliably. This is a challenging task in metrology since non-contact inspection techniques are required which offer micron uncertainties and high temporal resolution simultaneously, also under vacuum conditions. In order to meet these requirements, a non-incremental laser Doppler distance sensor system was developed using fiber and diffractive optics. In this paper we present for the first time high-speed deformation measurements of a cylindrical steel rotor using this novel sensor system. The radial rotor expansion of only some microns was determined despite the presence of an unsteady tumbling motion of the rotor, which was measured simultaneously. Future prospects are discussed including the possibility to measure non-metallic devices such as fiber-reinforced composites.     

利用AutoLISP的转子泵内转子仿真切削建模及应用

研究利用AutoLISP语言编程,模拟内、外转子啮合运动关系,仿真切削生成转子泵内转子精确三维模型.该模型可用于数控机床精确制造内转子零件或其成型模具.     

Full and partial boundary slippage effect on squeeze film bearings

Simple experiments were carried out to illustrate the effect of the boundary slippage on the load capacity of a squeeze film. The surface energy of the bearing surface was modified using laser excimer (UV laser). It was found that the load capacity can be reduced if the surfaces are modified to be hydrophobic. The boundary slippage effect on squeeze film was further studied theoretically to get more insight. The paper presents a mathematical model with a critical shear-stress criterion of slippage to describe the squeeze film effect. Three types of slippage, i.e. single zone partial slippage, single zone full slippage, and double zone partial slippage, are modeled. The analytical solution shows that the pressure distribution is a piecewise parabolic curve, where the pressure gradient can be discontinuous at the border of the slip and no-slip regions. Parametric studies illustrate the variations of the pressure and the boundary slippage under different conditions. It is demonstrated that with the increase of the length of the hydrophobic region, the maximum pressure does not increase continuously. Similar to the classical squeeze film bearing, the pressure decreases with the increase in the film thickness or the decrease in the approach velocity. The influences of the critical shear stress are also explored, and are found to significantly affect the squeeze behavior.     

基于CAN总线的液压同步滑移控制系统设计与实现

液压同步滑移是为解决施工中大跨度、大空间结构安装问题而发展起来的一项技术,其应用已经越来越广泛.为了达到控制精度高、响应速度快和布线简单的控制要求,系统采用了基于CAN总线的液压同步控制技术.阐述了基于CAN总线的液压同步滑移控制系统的组成及各节点硬件和软件设计.