带有集成前置器的位移传感器

对旋转机械的运行状态进行在线连续监测,目前采用最广泛的方法是用非接触式电涡流传感器对转轴直接测试。非接触式位移传感器是基于电涡流原理设计制造的,整个一次仪表测量回路是由探头、延伸电缆和前置器组成。 德国申克公司最近推出了一种集成化的电涡流位移传感器VIBRONECS,其设计思想是将涡流探     

电涡流传感器的特性分析与标定方法

结合电涡流传感器的原理,分析了采用电涡流传感器测量位移时传感器特性与被测体尺寸的关系,研究了不同被测材料对电涡流传感器灵敏度的影响,提出了电涡流传感器的标定方法。     

电涡流式压力传感器的研究

本文根据电涡流传感器的检测原理,从弹性元件的设计着手,通过力学分析,建立了压力与形变的数学表达式。在讨论电涡流检测电路的基础上,讨论了电涡流式压力传感器的变换原理,并通过实验检验,表明这种新型力传感器具有较好的应用特性,有着独特的优点。     

球体曲率变化对涡流传感器灵敏度影响

电涡流传感器的电磁场分布对传感器的灵敏度有重要影响,目前均将被检测体假设为平板导体进行电磁场仿真,并未考虑被测体为球体时其曲率半径对电涡流传感器灵敏度的影响。基于电涡流传感器的原理,利用有限元方法对电涡流传感器检测球体的电磁场分布进行了数值仿真分析,仿真结果与经典的电涡流理论相符,并由此验证模型的正确性。通过对不同曲率的球体进行电磁场仿真,研究分析了球体曲率对传感器灵敏度的影响,理论上为电涡流传感器检测球体零件时的优化设计提供了参考。     

电涡流传感器探头线圈的参数化设计与制造

探头线圈是电涡流传感器的最核心的部件,其设计参数对电涡流传感器的性能有直接影响。建立电涡流传感器探头线圈的等效模型,根据理论推导和ANSYS参数化建模仿真,分析探头线圈的设计参数对电涡流传感器线性度、灵敏度和测量范围的影响。根据所确定的设计参数,利用印刷电路板制造工艺,制作PCB板探头线圈,并测试了基于PCB板探头线圈的电涡流传感器的静态和动态性能。结果表明,PCB板探头线圈制造工艺成熟稳定,一致性很高,质量容易保证,基于PCB板探头线圈的电涡流传感器可以满足实际应用的需要。     

电涡流传感器的常见故障处理及安装方法

本文详细阐述了电涡流传感器的工作原理和系统组成,简单分析了电涡流传感器的常见故障和处理方法,介绍了电涡流传感器探头的安装方法,安装中的常见错误以及处理方法。     

电涡流传感器动态响应特性研究

为了提高磁悬浮轴承高频电主轴控制系统中电涡流传感器的动态响应特性,针对恒频调幅式电涡流位移振动传感器,分析了电涡流传感器的基本结构和工作原理,建立了电涡流传感器检测电路数学模型,分析了电涡流传感器动态响应特性与检测线圈谐振回路品质因数 Ｑ 的关系,提出了对电涡流传感器动态响应特性在不影响灵敏度和线性测量范围的情况下进行线性校正的方法,从而使电涡流传感器幅频响应带宽提高一倍甚至几倍以上,相位角的滞后量也可以大大减小,充分满足了对磁悬浮轴承高速转子进行位移和振动的非接触性监测的需要。     

大位移电涡流传感器的设计

电涡流传感器具有对介质不敏感、非接触的特点,广泛应用于对金属的距离检测中.为扩大电涡流传感器的检测范围,对电涡流传感器从理论上进行了分析,设计了基于恒定频率载波调幅法的振荡器及测量电路.利用Matlab仿真软件对Φ60 mm的电涡流传感器探头参数进行仿真,并结合设计的测量电路进行了实验.仿真研究和实验结果表明该电涡流传感器能够检测到70 mm的距离.     

电涡流传感器谐振测量电路参数的优化选择

为了满足磁悬浮轴承系统高精度的位移检测要求,必须对位移传感器的测量电路参数进行优化设计。文章从电涡流传感器的原理出发,介绍了谐振检测电路的工作原理,分析了谐振检测电路各参数对灵敏度的影响,提出了谐振测量电路参数优化的方法,利用这种参数优化方法来提高电涡流位移检测传感器的灵敏度简单、切实有效。     

电涡流传感器在电机换向器测试中的应用

设计出一套换向器跳动测试仪,用于测量直流电机换向器超速前后片间跳动和圆周跳动。根据电涡流传感器的测量原理,电涡流传感器将传感器探头与换向器片间的距离转换成电压值,再经过dsPIC30F6014数字信号控制器进行采集、处理、计算,并与上位机交换数据。给出了以dsPIC30F6014和电涡流传感器为核心的系统硬件设计和软件控制流程,并对实验结果进行了分析。该仪表既可以单独使用,也可以于上位机联合,实现测量系统的多功能化。     

Features of Eddy-Current Tests of Stepped Axial Bores in Rotors of Turbines of Thermal Power Plants

The paper reports on an investigation of parameters of the applied eddy-current transducer output in the presence of a cylindrical cavity with crack-like discontinuities and an interfering factor in the form of steps, i.e., local variations in the bore diameter. It has proven to be difficult to distinguish between a crack and a step when the recorded parameter is the signal amplitude; the method based on two parameters (amplitude and phase) allows one to get round the difficulties caused by the interfering factor.     

Eddy-current quality control of soldering of current-carrying joints in electrical machines. II. Experiment

The possibilities of the eddy-current method for quality control of soldering of joints of stator copper windings in electrical machines are studied. The contribution of closed eddy currents, which are induced in inspected joints by an eddy-current transducer and differ in perimeters and location depths of joints, to the signal of the eddy-current transducer is considered experimentally. The information content of eddy-current transducer signals is shown to be sufficient for estimating the soldering quality of joints of this type. The effect of various technological factors on the reliability of the inspection was determined.     

Features of dynamic addition of signals in two-frequency eddy-current testing

Shaping a signal carrying information using instantaneous values of the output voltage of an eddy-current transducer is considered. The main characteristic that determines the selection of the static or dynamic mode for shaping the informative signal is the system operator, through which the compensation for undesired factors in the testing technique is realized.     

Eddy-current testing of fatigue degradation under contact loading of NiCrBSi coatings obtained through gas–powder laser cladding

The possibilities of using the eddy-current method for testing the fatigue degradation under contact loading of NiCrBSi coatings were investigated. These coatings are obtained using the method of the gas–powder laser cladding from powders with different contents of chromium, boron, carbon, and additives of titanium carbide TiC (15 and 25 wt. %). It was established that eddy-current testing of fatigue degradation under contact loading of PG-SR2 and PG-10N-01 coatings can be performed at high excitation frequencies of an eddy-current transducer, when the depth of the analyzed layer is maximally close to the thickness of the surface layer that was subjected to fatigue degradation. Testing the fatigue degradation under contact loading of TiC–PG-SR2 composite coatings with TiC-additive contents of 15 and 25 wt. % has certain limitations and features that result from the presence of a significant number of discontinuity flaws in the structure of these coatings.     

The influence of a combined strain-heat treatment on the features of electromagnetic testing of fatigue degradation of quenched constructional steel

The possibilities of the magnetic and eddy-current methods for testing fatigue degradation during low-cycle loading of quenched steel 50 (0.51% C) that was subjected to a combined strain-heat treatment according to an optimal regime that included friction treatment with subsequent tempering at T = 350°C, were investigated. It is shown that for steel that was subjected to a combined nanostructuring treatment, the accumulation of a plastic strain under “hard” cyclic loading can be tested using the coercimetric method and values of the residual magnetic induction on the major and minor magnetic-hysteresis loops, values of the maximum and initial magnetic permeabilities, and readings of an eddy-current instrument at a low excitation frequency of the eddy-current transducer. The appearance of surface fatigue cracks can be tested via eddy-current measurements at high frequencies, when the contribution of the crack formation in the hardened layer to the eddy-current characteristics is considerable.     

A two-step algorithm for finite-element solution of electromagnetic-testing problems: Eddy-current testing

An algorithm for finite-element simulation of eddy-current testing problems is described. This algorithm allows calculation of transducer signals from any 3D flaw in a metallic item. In practice, the studied flaws are often characterized by small dimensions. Therefore, the measured increment of the voltage induced in the transducer’s output winding owing to the presence of such a flaw is only several percent of the voltage’s average value. If a standard calculation scheme based on the finite-element method is applied, significant computational resources are needed to solve this problem. The two-step algorithm allows a significant reduction in the required resources. The essence of the algorithm is that the source of the field of a flaw’s effect is determined from the distribution of eddy currents in metal free of flaws. Such an approach allows the calculations of the “unperturbed field” to be simplified significantly through consideration of the geometric symmetry of the problem solved and thus, through reduction of its dimensionality. The efficiency of the two-step algorithm is demonstrated during the solution of a typical problem: the use of a through differential transducer for eddy-current testing of a segment of a heat-exchange pipe in the steam generator of a nuclear power plant.     

Eddy-current quality control of soldering of current-carrying joints in electrical machines. I. General principles

The possibility of testing the electrical conductivity of soldered joints using and eddy-current transducer has been studied. The simplest model calculations allowing evaluation of the relative value of a signal from an inhomogeneity depending on its location inside a specimen are presented. It is shown that signals yielded by an eddy-current transducer are quite informative for determining the quality of soldering of current-carrying joints.     

An eddy-current gauge for measuring the wall thickness of light-alloy drill pipes

The operating principle and design of an eddy-current transducer intended for in-service measurement of the wall thickness of light-alloy drill pipes are described. The block diagram and algorithm of conversion are provided for measurement-data signals from the eddy-current thickness gauge. The main technical specs are listed for a thickness gauge prototype.     

Eddy-current testing of the wear resistance of laser-hardened carburized chromonickel steel and the quality of laser hardening of drill bits

Features of eddy-current testing of carburized chromonickel steel 30XH3A subjected to processing with continuous laser radiation, subsequent treatment with cold at s-196°C (reducing the content of retained austenite in the carburized layer from 25–40 to 5–10 vol %), and tempering in the temperature range 100–400°C are studied. It is shown that the eddy-current method can be used to detect the presence of a laser-hardened wear-resistant layer on the steel surface and evaluate an abrupt decrease in the abrasive wear resistance of steel hardened with laser radiation, additionally treated with cold, and then exposed to low-temperature tempering. The possibility of eddy-current testing of the quality of laser hardening of roller paths of the bearing unit of rock-drilling bits manufactured from carburized steel 20XH3A using an attachable transducer with a protruding rod core is established.