Journal articles on the topic 'Electromechanical protection device'
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1
Attary, Navid, M. Symans, and S. Nagarajaiah. "Development of a rotation-based negative stiffness device for seismic protection of structures." Journal of Vibration and Control 23, no. 5 (August 9, 2016): 853–67. http://dx.doi.org/10.1177/1077546315585435.
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Researchers worldwide have developed various semi-active control devices for seismic protection of structures. Most of these devices are electromechanical in nature and thus require a power source for their operation. In this paper, a newly developed rotation-based mechanical adaptive passive device is presented. These unique devices are able to mechanically change stiffness, either by adding positive or negative stiffness, by using different types of rotational elements. The devices are compact due to their use of rotational elements, facilitating their implementation in structures. The conceptual development of these devices is presented herein along with analytical models and numerical simulation results that demonstrate their potential for providing seismic protection. In addition, an extension of the stiffness modulation concept is introduced wherein damping is modulated.
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Vinogradov, A. V., A. V. Vinogradova, M. O. Ward, A. N. Kharkhardin, A. I. Psaryov, and T. I. Afanasyeva. "Choice of commutation device and development of the scheme of a universal sectionalizing point with automatic load transfer function for the 0.38 kV electric network." E3S Web of Conferences 124 (2019): 02011. http://dx.doi.org/10.1051/e3sconf/201912402011.
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The overestimated length of rural power lines of 0.38 kV leads to the fact that it is often not possible to fulfill both the sensitivity conditions of the protective device installed at the transformer substation and protecting the line from overloads and short circuits, and the requirements of the power supply reliability of consumers. This problem can be solved by installing in-line universal sectionalizing point equipped with an automatic load transfer function. The use of these devices allows dividing a line into sections provides the necessary sensitivity of protection for each section of the line and the possibility of supplying power to undamaged areas from a backup power source. In addition, only with the use of automated switching devices installed in power lines, it is possible to create intelligent electrical networks. When developing these devices, it is necessary to take into account the electromechanical characteristics of switching devices that are planned to be used for switching lines.
3
A., HADAI. "Overview of calculation verification methods of current transformers which work in relay protection circuits." Journal of Electrical and power engineering 27, no. 2 (November 28, 2022): 25–34. http://dx.doi.org/10.31474/2074-2630-2022-2-25-34.
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Systematized existing methods of calculation verification of current transformers that work in the circuits of modern relay protection devices. The requirements of the Ukrainian rules for the arrangement of electrical installations differ from the requirements of the standard of the International Electrotechnical Commission IES 61869-2. The difference concerns the absence of contact vibration and not exceeding the maximum allowable current error of 50% in the case of an internal short circuit is a separate case of the requirements for electromechanical protections and these requirements cannot be used for microprocessor protection devices. For any relay protection device, there is no concept of the permissible value of "voltages at the current inputs". The voltage at the terminals of the secondary winding and the voltage at the "input of the relay protection device" are two completely different voltages. There are no methods for calculating errors in the case of switching on protection based on the sum of the currents. Companies producing microprocessor relay protection devices specify in their instructions individual requirements for current transformers for each individual device. Compliance with these requirements guarantees the correct operation of the relay protection even for large values of the time constant of the primary network. Leading manufacturers of microprocessor relay protection devices develop and recommend software tools for checking the correct selection of current transformers. But they are not freely available. To increase the accuracy of the calculation of the limit multiplicity, it is advisable to use complex supports of the secondary winding and load of current transformers. Depending on the initial data and conditions, the permissible load resistance can be calculated using four methods. The question of whether the allowable load of a current transformer can exceed its nominal load requires further research. The scientific novelty is consists in the systematization of existing methods of calculation verification of current transformers that work in the circles of modern relay protection devices. The practical significance of the work is that checking current transformers that are connected to microprocessor relay protection devices do not need to check the maximum permissible current error of 50%; to check the correct operation of microprocessor relay protection devices, it is advisable to use the instructions for the requirements for current transformers of device manufacturers; for a more accurate calculation of the limit multiplicity, it is advisable to use complex supports of the secondary winding and load of current transformers.
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Chirca, Mihai, Marius Dranca, Claudiu Alexandru Oprea, Petre-Dorel Teodosescu, Alexandru Madalin Pacuraru, Calin Neamtu, and Stefan Breban. "Electronically Controlled Actuators for a Micro Wind Turbine Furling Mechanism." Energies 13, no. 16 (August 14, 2020): 4207. http://dx.doi.org/10.3390/en13164207.
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This paper presents two electromechanical systems used for the overspeed protection of small wind turbines. The actuators have the purpose of rotating the back rudder (tail vane) of the wind turbine when the blades are overspeeding. The rudder rotation angle is 90 degrees in order to completely turn the wind turbine blades away from the wind flow direction. The first device is a new limited-angle torque electromechanical actuator consisting of a device with a simplified structure composed of four permanent magnets (two on each side) glued on a rotor mounted between two stator poles built from ordinary rectangular construction pipes and an electronic control unit. The second device is based on a regular stepper motor actuator with a reduction gear and an appropriate control scheme to maximize the energy harvested at high, over-nominal wind speeds. A generic comparison is provided for the proposed solutions.
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Anderson, David A., Andrew D. Brown, Nathaniel Greene, Theodore F. Argo, and Bruno Mary. "Development of an in-ear microphone for individualized measurement of hearing protection device output." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A57. http://dx.doi.org/10.1121/10.0010644.
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Hearing protection devices (HPDs) are designed to reduce the amplitude of sound reaching the ear, but can also distort the acoustical cues necessary for sound localization. In order to quantify the acoustic impact of an HPD on the signal reaching the tympanic membrane, the signals deep in the ear canal with and without the HPD must be compared. While some commercial microphone solutions for measuring in-ear pressures with HPDs exist, they are device-specific and/or may not provide reliable isolation of the microphone transducer from the (potentially high-intensity) ambient sound field. Here, we describe a new assembly using a small MEMS microphone attached to the end of a thin flexible circuit, which can be inserted either alongside or through virtually any HPD. Following a description of the electromechanical design of the assembly, we present measurements of insertion loss for HPDs with and without the microphone using an acoustic test fixture. These measurements demonstrate that the presence of the microphone does not significantly disrupt the sound attenuation characteristics of a range of HPDs. Preliminary measurements of insertion loss and head-related transfer functions in human subjects are also presented.
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Seetharaman, Krishnan, Bart van Velzen, Johannes van Wingerden, Hans van Zadelhoff, Cadmus Yuan, Frank Rietveld, Coen Tak, Joost van Beek, Peter H. C. Magnée, and Herman C. W. Beijerinck. "A Robust Thin-Film Wafer-Level Packaging Approach for MEMS Devices." Journal of Microelectronics and Electronic Packaging 7, no. 3 (July 1, 2010): 175–80. http://dx.doi.org/10.4071/imaps.270.
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Micro-electromechanical systems (MEMS) devices are extremely sensitive to their environment, especially at the wafer level, until they are packaged in final form. The harsh back-end (BE) operations that the MEMS devices have to endure include dicing, pick-and-place, wire bonding, and molding. During these processing steps, the MEMS device is exposed to particles and contaminants. Therefore, protection at an early stage is a fundamental requirement. We describe a silicon nitride thin-film capping, which is processed using a sacrificial layer technique only with front-end technology. This approach is suitable for mass production of MEMS devices, owing to the fact that it is more cost-effective when compared to other approaches such as wafer-to-wafer bonding and die-to-wafer bonding. A bulk acoustic wave (BAW) resonator that finds application in the radio frequency (RF) front end, for example, in cell phones, is taken as a MEMS vehicle for our work. It is an example of an extremely sensitive MEMS device, because the resonance frequency shifts significantly when additional mass is accidentally deposited on its surface. The thickness of the silicon nitride capping that is required to withstand all the BE steps, in particular transfer molding, is estimated using simple analytical calculations and finite element model (FEM) simulations. The pressure acting on the thin film capping and the thermal load during molding are included in the FEM model. Using this, the minimum thickness required for the capping is determined. We prove that a BAW resonator capped with silicon nitride at the wafer level can be wafer-thinned, diced, wire bonded, and molded without major degradation in performance.
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Seetharaman, Krishnan, Bart van Velzen, Hans van Zadelhoff, Cadmus Yuan, Frank Rietveld, Coen Tak, Joost van Beek, et al. "A Robust Wafer-Level Capping Approach for MEMS Devices." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2010, DPC (January 1, 2010): 000891–924. http://dx.doi.org/10.4071/2010dpc-tp21.
Full textAbstract:
Micro-electromechanical systems (MEMS) devices are extremely sensitive to their environment, especially at wafer-level, until they are packaged in final form. The harsh back-end (BE) operations that the MEMS devices have to endure include dicing, pick-and-place, wire bonding and molding. During these processing steps, the MEMS device is exposed to particles and contaminants. Therefore, protection at an early stage is a fundamental requirement. In this work, we describe a silicon nitride thin-film capping, which is processed using a sacrificial layer technique only with front-end technology. This approach is suitable for mass production of MEMS devices, owing to the fact that, it is more cost-effective when compared to other approaches such as wafer-to-wafer bonding and die-to-wafer bonding. A Bulk Acoustic Wave (BAW) resonator, that finds application in the Radio Frequency (RF) front end, e.g., in cell phones, is taken as a MEMS vehicle for our work. It is an example of an extremely sensitive MEMS device, because the resonance frequency shifts significantly when additional mass is accidentally deposited on its surface. The thickness of the silicon nitride capping that is required to withstand all the BE steps, in particular transfer molding, is estimated using simple analytical calculations and finite element model (FEM) simulations. The pressure acting on the thin film capping and the thermal load during molding are included in the FEM model. Using this, the minimum thickness required for the capping is determined. We prove that, a BAW resonator capped with silicon nitride at wafer-level can be wafer-thinned, diced, wire bonded and molded without major degradation in its performance.
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Nie, Xiao Yu, Zhi Xiang Li, Lei Bai, and Geng Weng. "Research and Realization for the System of Coal Mine Ventilation System." Advanced Materials Research 383-390 (November 2011): 4603–11. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.4603.
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Coal mining is an integrated trade which involves the geology, well ventilated, transportation, electricity and environmental protection and so on. The mining industry has labor intensity, bad work condition, many harm factors. Each kind of virulent noxious gas, coal dust, fire, electromechanical device are all immediate danger to operate personnel's safety and healthy. Well-balanced and suitable ventilation is the postulate to keep the health of underground worker and the safety of the production. We take air quantity of laneway as the research emphasis, considering the release of state regulations on coal min. We figure out the optimum area of air quantity via building the optimization programming model, and realize an actual case study to interpret the process of the probabilistic risk analysis (PRA) with statistic theory. We take the theory to the actual production. We establish a MIS base on the theory. In the process of establishing the system, we use the object-oriented analysis method and the B/S structure, take JAVA as the development kit, and realize the risk analysis system. Then the risk manager can take the corresponding monitoring measure.
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Contell Asins, Conchin, Volker Landersheim, Dominik Laveuve, Seiji Adachi, Michael May, Jens-David Wacker, and Julia Decker. "Analysis and Design of a Leading Edge with Morphing Capabilities for the Wing of a Regional Aircraft—Gapless Chord- and Camber-Increase for High-Lift Performance." Applied Sciences 11, no. 6 (March 19, 2021): 2752. http://dx.doi.org/10.3390/app11062752.
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In order to contribute to achieving noise and emission reduction goals, Fraunhofer and Airbus deal with the development of a morphing leading edge (MLE) as a high lift device for aircraft. Within the European research program “Clean Sky 2”, a morphing leading edge with gapless chord- and camber-increase for high-lift performance was developed. The MLE is able to morph into two different aerofoils—one for cruise and one for take-off/landing, the latter increasing lift and stall angle over the former. The shape flexibility is realised by a carbon fibre reinforced plastic (CFRP) skin optimised for bending and a sliding contact at the bottom. The material is selected in terms of type, thickness, and lay-up including ply-wise fibre orientation based on numerical simulation and material tests. The MLE is driven by an internal electromechanical actuation system. Load introduction into the skin is realised by span-wise stringers, which require specific stiffness and thermal expansion properties for this task. To avoid the penetration of a bird into the front spar of the wing in case of bird strike, a bird strike protection structure is proposed and analysed. In this paper, the designed MLE including aerodynamic properties, composite skin structure, actuation system, and bird strike behaviour is described and analysed.
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Flaxer, Eli. "Principles, design and implementation of a direct AC-to-AC power converter—Regulated electronic transformer." Review of Scientific Instruments 93, no. 11 (November 1, 2022): 114710. http://dx.doi.org/10.1063/5.0122782.
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In the last three decades, the energy conversion market has been dominated by switching power converters due to reduction of size and cost of electronic components. This market includes four types of conversion: DC–DC, DC–AC, AC–DC, and AC–AC. While the first three types are applied directly in a single conversion, the AC–AC converter is comprised of two serial converters leading to an AC–DC–AC conversion. This article introduces, for the first time, a real direct single-stage AC–AC conversion electronic transformer. The single stage AC–AC converter is fabricated using a unique high efficiency topology, combined with the advantages of dual-stage power-quality protection. This single-stage AC–AC regulated electronic transformer is stabilized, controlled, protected, and can lock onto any line voltage (110 or 220 V) with a frequency of 45–65 Hz. Stabilization is achieved by fast pulse-width modulation technology, applied by two-way fast solid-state switches. The transformer is controlled by a 150 MHz digital signal processor and is fully protected against overcurrent and output short circuits. Our first stage transformer is a single-phase device with 5 kW power with an efficiency of better than 97% with one-tenth of the weight and volume of present conventional electromechanical transformers.
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Varlamov, V. V., M. V. Kipervasser, and A. V. Gerasimuk. "Modeling of overloads of raising mechanism in metallurgical overhead cranes." Izvestiya. Ferrous Metallurgy 62, no. 8 (September 13, 2019): 646–51. http://dx.doi.org/10.17073/0368-0797-2019-8-646-651.
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Electromechanical processes occurring when the load is lifted by an overhead crane are considered. The main idea of the work is to identify emergency mode (crane overload) by a method based on control of stator current of lift motor. To obtain stator current diagrams of electric motor, mathematical model of overhead crane (three-mass circuit) has been developed, which includes equations describing elastic properties of crane beams and its rope. A system of (α, β) coordinates, fixed relative to electric motor stator, is adopted to describe the drive asynchronous motor. Lifting cycle is considered as sequence of three steps: choice of the rope “slack”; rope tension; separation of cargo lifting. For each stage, a system of differential equations has been compiled describing motion of masses of overhead crane elements and electrical parameters of electric motor. Initial and boundary conditions for each of the stages were determined. Preliminary transformations of the system of equations to their solution by numerical methods and subsequent modeling of stages of lifting loads were carried out for different weights. Sequential solution of three boundary value problems allows obtaining values of stator currents at time of load separation. Diagrams of stator phase currents of an electric motor were obtained for loads of different mass. Simulation results indicate the presence of fixable difference in magnitudes of stator currents after the load is separated from the support surface. On basis of the developed model and the study results, a functional diagram of crane overload protection device is proposed and its principle of operation is described. It consists in controlling lifted load mass and stator current when liftingthe load. Conclusion is made about feasibility and effectiveness of monitoring electrical values of lifting motor for development of overhead crane protection against overloads. Effectiveness of the proposed system was evaluated.
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Gurevich, Vladimir. "Hybrid reed: Solid-state devices are a new generation of protective relays." Serbian Journal of Electrical Engineering 4, no. 1 (2007): 85–94. http://dx.doi.org/10.2298/sjee0701085g.
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Research and development in the field of electromechanical protective relays has not been conducted for tens of years. Author?s approach allows viewing the problem of re-equipment of relay protection in a new way. In the author?s opinion combination of reed switches with magnetic circuits and semiconductor elements opens new avenues in development of the promising protective relays featuring reliability, simplicity and low cost. Examples of protective relays made with these elements are given below.
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Argo, Theodore F., Andrew D. Brown, David J. Audet, Nathaniel Greene, Caylin R. McCallick, Carol A. Sammeth, David A. Anderson, and Gregory T. Rule. "Methods for validation of electromechanical evaluation of hearing protection." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A216. http://dx.doi.org/10.1121/10.0011097.
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Preventing hearing injury while maintaining situational awareness is of critical importance while using hearing protection devices (HPDs). Determining the optimal HPD for such varied conditions as operating machinery, riding in aircraft, and using firearms is a non-trivial task. Currently, the Noise Reduction Rating (NRR) is the only required HPD specification; other important characteristics of advanced HPDs are not reported in a standardized manner despite the availability of relevant test standards. Barriers to standardized performance reporting are the use of human subjects and the range of performance capabilities of commercially available HPDs. To complement existing test standards and support standardization of performance reporting across a broader range of performance capabilities, a suite of quantitative, sensor-based tests is being developed to quickly, inexpensively, and comprehensively evaluate candidate HPDs. The five-test battery evaluates signal quality, sound localization, level-dependent frequency response, electronic self-noise, and impulse noise response. In parallel, a set of human subject tests is being developed to validate the electromechanical metrics. Here, we will present (1) preliminary results comparing human performance with complementary electromechanical data and (2) a software tool under development incorporating the electromechanical tests to optimize HPD selection for application-specific hearing protection.
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Wang, Jianjun, Weijie Li, Lei Qin, Jing Zhang, and Peijun Wei. "Effects of electrodes and protective layers on the electromechanical characteristics of piezoelectric stack actuators." Advanced Composites Letters 28 (January 1, 2019): 096369351987741. http://dx.doi.org/10.1177/0963693519877419.
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Piezoelectric stack actuators are a type of excellent smart devices that can activate large power and displacement outputs due to their unique stack configuration and have been widely used in linear vibrators for various engineering applications. For the fabricated piezoelectric stack actuator, it usually consists of multiple thin piezoelectric wafers, multiple electrodes, and two protective layers. All the piezoelectric wafers are connected electrically in parallel through the electrodes and are protected by two protective layers at the two ends. However, in most of the theoretical models, the active piezoelectric portion is mainly considered, while the electrodes and protective layers are usually neglected to simplify the complicated problem, which results in an inaccurate prediction of the electromechanical characteristics. In our previously published work, the exact theoretical models of the piezoelectric stack energy harvester and sensor with the electrodes and the protective layers included have been established successfully to evaluate the electromechanical performance of these two types of devices, and their validity has verified by the experimental results. However, the exact theoretical model of the piezoelectric stack actuators has not been established, and the effects of the electrodes and the protective layers on the electromechanical characteristics of the actuator are not fully understood. In this article, the exact theoretical model of piezoelectric stack actuator was derived based on our previous work, and the effects of these two factors on the electromechanical characteristics were investigated. Comparisons with the results in the earlier literatures and the experimental results were presented to validate the model. Furthermore, two kinds of typical working states, including clamped–free (C-F) and free–free (F-F), were discussed. The results showed that neglecting the electrodes and the protective layers will greatly affect the accuracy of the prediction model, thus providing some valuable guidelines in designing the piezoelectric stack actuators.
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Alonso, Monica, Hortensia Amaris, Daniel Alcala, and Diana M. Florez R. "Smart Sensors for Smart Grid Reliability." Sensors 20, no. 8 (April 13, 2020): 2187. http://dx.doi.org/10.3390/s20082187.
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Sensors for monitoring electrical parameters over an entire electricity network infrastructure play a fundamental role in protecting smart grids and improving the network’s energy efficiency. When a short circuit takes place in a smart grid it has to be sensed as soon as possible to reduce its fault duration along the network and to reduce damage to the electricity infrastructure as well as personal injuries. Existing protection devices, which are used to sense the fault, range from classic analog electro-mechanics relays to modern intelligent electronic devices (IEDs). However, both types of devices have fixed adjustment settings (offline stage) and do not provide any coordination among them under real-time operation. In this paper, a new smart sensor is developed that offers the capability to update its adjustment settings during real-time operation, in coordination with the rest of the smart sensors spread over the network. The proposed sensor and the coordinated protection scheme were tested in a standard smart grid (IEEE 34-bus test system) under different short circuit scenarios and renewable energy penetration. Results suggest that the short-circuit fault sensed by the smart sensor is improved up to 80% and up to 64% compared with analog electromechanics relays and IEDs, respectively.
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Debéda, Hélène, Maria-Isabel Rua-Taborda, Onuma Santawitee, Simon Grall, Mario Maglione, U.-Chan Chung, and Catherine Elissalde. "The Role of Sacrificial and/or Protective Layers to Improve the Sintering of Electroactive Ceramics: Application to Piezoelectric PZT-Printed Thick Films for MEMS." Ceramics 3, no. 4 (November 16, 2020): 453–75. http://dx.doi.org/10.3390/ceramics3040038.
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Piezoelectric thick films are of real interest for devices such as ceramic Micro-ElectroMechanical Systems (MEMS) because they bridge the gap between thin films and bulk ceramics. The basic design of MEMS includes electrodes, a functional material, and a substrate, and efforts are currently focused on simplified processes. In this respect, screen-printing combined with a sacrificial layer approach is attractive due to its low cost and the wide range of targeted materials. Both the role and the nature of the sacrificial layer, usually a carbon or mineral type, depend on the process and the final device. First, a sacrificial layer method dedicated to screen-printed thick-film ceramic and LTCC MEMS is presented. Second, the recent processing of piezoelectric thick-film ceramic MEMS using spark plasma sintering combined with a protective layer approach is introduced. Whatever the approach, the focus is on the interdependent effects of the microstructure, chemistry, and strain/stress, which need to be controlled to ensure reliable and performant properties of the multilayer electroceramics. Here the goal is to highlight the benefits and the large perspectives of using sacrificial/protective layers, with an emphasis on the pros and cons of such a strategy when targeting a complex piezoelectric MEMS design.
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Zhang, Yan Hua, Xue Jiao, Ying Ying Zhong, Jun Chi Zhou, and Ju Yuan. "Application of Mobile Data Acquisition Technology in Highway Lightning Protection." Applied Mechanics and Materials 596 (July 2014): 498–504. http://dx.doi.org/10.4028/www.scientific.net/amm.596.498.
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The inspection of lightning protection system is developing gradually presently,while it is still in a relatively backward stage, data acquisition method is old, measuring conclusion is not real-time, data measurement is out of line with the standardization of lightning business. The service area and toll station of highway prone to lightning strikes for the isolated location. Meantime, there is no lightning protection facility or facilities are not perfect, lightning accidents happen sometime which caused heavy losses to the highway with a lot of sensitive electronic equipment. The inspection of highway lightning protection should be strengthened, the mobile data acquisition technology is introduced to the highway lightning inspection in order to make the lightning protection devices play an effective role. The data acquisition process and application are described, it can ensure the diversification of data, the real-time transmission of field testing data, further standardization of the lightning inspection process and the quality of inspection to ensure safe and effective operation of building and electromechanical systems.
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Kuzhekov, Stanislav, Andrey Degtyarev, Nikolay Doni, and Aleksey Shurupov. "On the Problem of Selecting and Replacing Current Transformers for Relay Protection Devices." Известия высших учебных заведений. Электромеханика 63, no. 6 (2020): 72–82. http://dx.doi.org/10.17213/0136-3360-2020-6-72-82.
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In connection with cases of incorrect operation of high-speed relay protection devices (RPD) in case of short circuits outside their range, the issue of replacing current transformers (CT) of class P with more ad-vanced current converters is relevant. The article shows that the decision to replace existing class P CTs with CTs with a non-magnetic gap should be made taking into account the probability of saturation of the magnetic cores of the latter in a transient short-circuit mode, as well as an increase in their dimensions compared to class P CTs. The issue of using optoelectronic current converters should be resolved after the latter are put into mass production, taking into account the difficulty of integrating the latter with the RPDs implemented using an Electromechanical base. In many cases, the correct functioning of high-speed RPDs without replacing existing CTs of class P can provide the following measures: the use of algorithms that increase the stability of the oper-ation of high-speed RPDs when the CT is saturated; taking into account in the calculations of the settings the rectangular characteristic of the CT magnetization in transient modes and the permissible deceleration of pro-tections under the condition of the dynamic stability of electric power systems; refusal to use CT connection groups (physical sum of currents, delta and star).
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Rubes, Ondrej, Zdenek Machu, Oldrich Sevecek, and Zdenek Hadas. "Crack Protective Layered Architecture of Lead-Free Piezoelectric Energy Harvester in Bistable Configuration." Sensors 20, no. 20 (October 14, 2020): 5808. http://dx.doi.org/10.3390/s20205808.
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Kinetic piezoelectric energy harvesters are used to power up ultra-low power devices without batteries as an alternative and eco-friendly source of energy. This paper deals with a novel design of a lead-free multilayer energy harvester based on BaTiO3 ceramics. This material is very brittle and might be cracked in small amplitudes of oscillations. However, the main aim of our development is the design of a crack protective layered architecture that protects an energy harvesting device in very high amplitudes of oscillations. This architecture is described and optimized for chosen geometry and the resulted one degree of freedom coupled electromechanical model is derived. This model could be used in bistable configuration and the model is extended about the nonlinear stiffness produced by auxiliary magnets. The complex bistable vibration energy harvester is simulated to predict operation in a wide range of frequency excitation. It should demonstrate typical operation of designed beam and a stress intensity factor was calculated for layers. The whole system, without presence of cracks, was simulated with an excitation acceleration of amplitude up to 1g. The maximal obtained power was around 2 mW at the frequency around 40 Hz with a maximal tip displacement 7.5 mm. The maximal operating amplitude of this novel design was calculated around 10 mm which is 10-times higher than without protective layers.
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Prokopchuk, Artem, Ivan Zozulia, Yurii Didenko, Dmytro Tatarchuk, Henning Heuer, and Yuriy Poplavko. "Dielectric Permittivity Model for Polymer–Filler Composite Materials by the Example of Ni- and Graphite-Filled Composites for High-Frequency Absorbing Coatings." Coatings 11, no. 2 (February 1, 2021): 172. http://dx.doi.org/10.3390/coatings11020172.
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The suppression of unnecessary radio-electronic noise and the protection of electronic devices from electromagnetic interference by the use of pliable highly microwave radiation absorbing composite materials based on polymers or rubbers filled with conductive and magnetic fillers have been proposed. Since the working frequency bands of electronic devices and systems are rapidly expanding up to the millimeter wave range, the capabilities of absorbing and shielding composites should be evaluated for increasing operating frequency. The point is that the absorption capacity of conductive and magnetic fillers essentially decreases as the frequency increases. Therefore, this paper is devoted to the absorbing capabilities of composites filled with high-loss dielectric fillers, in which absorption significantly increases as frequency rises, and it is possible to achieve the maximum frequency selective of absorption due to electromagnetic and electromechanical resonances.
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Argo, Theodore F., David A. Anderson, Andrew D. Brown, Nathaniel Greene, and Jennifer Jerding. "Development of an electromechanical test system and acoustical metrics to predict impacts of hearing protection devices on sound localization." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A165. http://dx.doi.org/10.1121/10.0010990.
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Hearing protection devices (HPDs) such as earplugs and earmuffs can protect users from dangerously high acoustical pressures but also distort cues important for the spatial localization of sounds, likely through spectral distortions associated with occlusion of the pinnae. Evaluation of the degree to which an HPD distorts localization cues is essential for critical situations where users must be protected from high pressures but maintain spatial awareness. Automated testing offers several prospective advantages over human subject testing including cost, speed, and repeatability. In this paper, we describe an electromechanical system using a rotating manikin test fixture and a speaker on a track to simulate a hemispheric speaker array. The sound source localization impact of an HPD is estimated by comparing test signals recorded by the manikin with and without an HPD in place. Test results, as a function of sound source azimuth and elevation in the virtual speaker array, and as an average across locations, are shown for a variety of HPDs. Results are compared to an initial set of parallel measurements of sound localization during HPD use in human subjects.
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Chandra, Sudhir, and Atul Vir Singh. "Preparation and Characterization of Piezoelectric Films of ZnO and AlN by RF Sputtering for RF MEMS Applications." Key Engineering Materials 500 (January 2012): 84–89. http://dx.doi.org/10.4028/www.scientific.net/kem.500.84.
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In present work, we report preparation and characterization of piezoelectric films of zinc oxide (ZnO) and aluminum nitride (AlN) by RF magnetron sputtering using respective ceramic targets. The effect of ambient gas, substrate temperature, RF power and sputtering pressure has been studied to get highly c-axis oriented films for potential applications in micro-electromechanical systems. The films were characterized by X-ray diffraction technique to identify the crystallographic orientation. It was observed that the film deposited in pure Argon (Ar) ambient were amorphous or weekly crystallized with no preferred (002) orientation. On the other hand, the films prepared in Ar-O2 for ZnO were highly c-axis oriented. Similarly AlN films were observed to be oriented along c-axis perpendicular to substrate only when deposited in mixture of Ar-N2. To demonstrate the application of piezoelectric properties, an FBAR device (Film Bulk Acoustic Resonator) using ZnO thin film was fabricated. ZnO films are very sensitive to the chemicals used in the micro-electro-mechanical systems (MEMS) fabrication processes which include acids, bases and etchants of different material layers (e.g. SiO2, chromium, gold etc.). A specially designed mechanical jig was used for physically protecting the film during Si anisotropic etching process in potassium hydroxide solution. The potential applications of these films in various RF MEMS devices have been discussed.
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Hu, Shuaishuai, Jiansheng Liu, and Junlin Li. "Fracture Analysis of Griffith Interface Crack in Fine-Grained Piezoelectric Coating/Substrate under Thermal Loading." Advances in Mathematical Physics 2020 (September 15, 2020): 1–15. http://dx.doi.org/10.1155/2020/4201591.
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Coating often plays a role in monitoring and protecting substrates in engineering applications. Interface cracks between the coating and the substrate can lead to crack growth under the action of external loading and will cause device failure. In this paper, the behavior of a fine-grained piezoelectric coating/substrate with a Griffith interface crack under steady-state thermal loading is studied. The temperature field, displacement field, and electric field of the coupling of thermal and electromechanical problems are constructed via integral transformation and the principle of superposition. Thus, problems are transformed into a system of singular integral equations, and the expressions of thermal intensity factor, thermal stress intensity factor, and electric displacement intensity factor are obtained. We used a numerical calculation and a system of singular equations to obtain the relationship of strength factor with material parameters, coating thickness, and crack size.
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SZCZĘCH, Marcin, Wojciech HORAK, and Józef SALWIŃSKI. "THE INFLUENCE OF SELECTED PARAMETERS ON MAGNETIC FLUID SEAL TIGHTNESS AND MOTION RESISTANCE." Tribologia, no. 4 (August 31, 2017): 71–76. http://dx.doi.org/10.5604/01.3001.0010.5997.
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Magnetic fluid seals belong to the class of non-contact seals. They are used as protective seals for vacuum systems, high speed shafts, precision mechanics, and electromechanical devices. The proper functioning of the magnetic fluid seal is related to creating and maintaining the continuity of the fluid ring on the sealing stage. This is achieved by appropriately shaped magnetic field distribution in the region of the sealing stage. Consequently, one of the main issues with the construction of such seals is to determine the distribution of the magnetic field in this region. This paper presents the results of analytical calculations and numerical simulations, based on which the influence of selected geometric parameters on the critical pressure and motion resistance was determined.
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Böhnke, Philippa Ruth Christine, Hans Winger, Florian Wieczorek, Mareen Warncke, Lisa Marie Lüneburg, Iris Kruppke, Andreas Nocke, Eric Häntzsche, and Chokri Cherif. "Protective Coating for Electrically Conductive Yarns for the Implementation in Smart Textiles." Solid State Phenomena 333 (June 10, 2022): 11–20. http://dx.doi.org/10.4028/p-9q3n92.
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The Cluster of Excellence “Centre for Tactile Internet with Human-in-the-Loop (CeTI)” deals with developments and inventions concerning smart devices used in many fields, e.g. industry 4.0, medicine and skill learning. These kind of applications require smart devices, sensors, actors and conductive structures. Textile structures address these applications by meeting requirements such of being flexible, adaptable and wearable. Within this paper, the development of a protective coating for electrically conductive (EC) yarns is captured. These EC yarns are nowadays often used for smart textile applications. One challenge in their application is the integration into textile structures. Often, the handling and use of EC yarns lead on the one hand to damages on the surface of the yarn and on the other hand to reduced electromechanically characteristics. This paper aims to characterize these EC yarns in regard to develop a suitable protective coating based on polypropylene (PP). To achieve this development, an extensive characterization of the EC yarns as well as the protective coating itself is important. The surface free energy (SFE), the topographical and the chemical characteristics are necessary for developing a suitable protective coating. However, the yarns are characterized before and after implementation into the textile structure and furthermore after the coating respectively with the developed finish.
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Ma, Jianxing. "Study on Electric Card Effect of Lead-free Piezoelectric Ceramics." Highlights in Science, Engineering and Technology 27 (December 27, 2022): 285–91. http://dx.doi.org/10.54097/hset.v27i.3769.
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The electrocaloric effect of ferroelectric materials can be used for refrigeration. This new method has the advantage of high efficiency, environmental protection and lower cost. Its variable size can satisfy the cooling requirements of different devices. However, it still exist some problems of lead-free ferroelectric ceramics refrigeration: its refrigeration temperature is less than 1 K; refrigeration temperature range is narrow; working temperature is either too high or too low. Sodium bismuth titanate (Na0.5Bi0.5TiO3, NBT) material stands out and becomes the most promising candidate to replace lead-based materials. Properties of NBT almost meet the test requirements. Near depolarization temperature, this material shows ferroelectric/antiferroelectric phase transition, which brings a larger change in electric heating temperature. In this paper, electric card effect, lead-free piezoelectric ceramic materials and the BNT-xST ceramics were introduced in detail. Among these materials, BNT-xST is considered to be a promising material due to its excellent ferroelectric property and large electromechanical coupling coefficient.
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Smirnov, Alexandr, and Dmitriy Kudriashov. "Enhancement of Electromechanical Devices of the Rate Control of the Lowering Adjusting Gear of the Actuators of the System Control and Protection of Nuclear Reactors." Известия высших учебных заведений. Электромеханика, no. 5 (2016): 25–30. http://dx.doi.org/10.17213/0136-3360-2016-5-25-30.
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Jõgiaas, Taivo, Aivar Tarre, Hugo Mändar, Jekaterina Kozlova, and Aile Tamm. "Nanoindentation of Chromium Oxide Possessing Superior Hardness among Atomic-Layer-Deposited Oxides." Nanomaterials 12, no. 1 (December 29, 2021): 82. http://dx.doi.org/10.3390/nano12010082.
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Chromium (III) oxide is a technologically interesting material with attractive chemical, catalytic, magnetic and mechanical properties. It can be produced by different chemical and physical methods, for instance, by metal–organic chemical vapor deposition, thermal decomposition of chromium nitrate Cr(NO3)3 or ammonium dichromate (NH4)2Cr2O7, magnetron sputtering and atomic layer deposition. The latter method was used in the current work to deposit Cr2O3 thin films with thicknesses from 28 to 400 nm at deposition temperatures from 330 to 465 °C. The phase composition, crystallite size, hardness and modulus of elasticity were measured. The deposited Cr2O3 thin films had different structures from X-ray amorphous to crystalline α-Cr2O3 (eskolaite) structures. The averaged hardness of the films on SiO2 glass substrate varied from 12 to 22 GPa and the moduli were in the range of 76–180 GPa, as determined by nanoindentation. Lower values included some influence from a softer deposition substrate. The results indicate that Cr2O3 could be a promising material as a mechanically protective thin film applicable, for instance, in micro-electromechanical devices.
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Kim, Tae, Jee-Hwan Bae, Juyoung Kim, Min Cho, Yu-Chan Kim, Sungho Jin, and Dongwon Chun. "Curved Structure of Si by Improving Etching Direction Controllability in Magnetically Guided Metal-Assisted Chemical Etching." Micromachines 11, no. 8 (July 30, 2020): 744. http://dx.doi.org/10.3390/mi11080744.
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Metal-assisted chemical etching (MACE) is widely used to fabricate micro-/nano-structured Si owing to its simplicity and cost-effectiveness. The technique of magnetically guided MACE, involving MACE with a tri-layer metal catalyst, was developed to improve etching speed as well as to adjust the etching direction using an external magnetic field. However, the controllability of the etching direction diminishes with an increase in the etching dimension, owing to the corrosion of Fe due to the etching solution; this impedes the wider application of this approach for the fabrication of complex micro Si structures. In this study, we modified a tri-layer metal catalyst (Au/Fe/Au), wherein the Fe layer was encapsulated to improve direction controllability; this improved controllability was achieved by protecting Fe against the corrosion caused by the etching solution. We demonstrated curved Si microgroove arrays via magnetically guided MACE with Fe encapsulated in the tri-layer catalyst. Furthermore, the curvature in the curved Si microarrays could be modulated via an external magnetic field, indicating that direction controllability could be maintained even for the magnetically guided MACE of bulk Si. The proposed fabrication method developed for producing curved Si microgroove arrays can be applied to electronic devices and micro-electromechanical systems.
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Li, Cheng, Zijin Pan, Xunyu Li, Weiquan Hao, Runyu Miao, and Albert Wang. "Selective Overview of 3D Heterogeneity in CMOS." Nanomaterials 12, no. 14 (July 8, 2022): 2340. http://dx.doi.org/10.3390/nano12142340.
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As the demands for improved performance of integrated circuit (IC) chips continue to increase, while technology scaling driven by Moore’s law is becoming extremely challenging, if not impractical or impossible, heterogeneous integration (HI) emerges as an attractive pathway to further enhance performance of Si-based complementary metal-oxide-semiconductor (CMOS) chips. The underlying basis for using HI technologies and structures is that IC performance goes well beyond classic logic functions; rather, functionalities and complexity of smart chips span across the full information chain, including signal sensing, conditioning, processing, storage, computing, communication, control, and actuation, which are required to facilitate comprehensive human–world interactions. Therefore, HI technologies can bring in more function diversifications to make system chips smarter within acceptable design constraints, including costs. Over the past two decades or so, a large number of HI technologies have been explored to increase heterogeneities in materials, technologies, devices, circuits, and system architectures, making it practically impossible to provide one single comprehensive review of everything in the field in one paper. This article chooses to offer a topical overview of selected HI structures that have been validated in CMOS platforms, including a stacked-via vertical magnetic-cored inductor structure in CMOSs, a metal wall structure in the back end of line (BEOL) of CMOSs to suppress global flying noises, an above-IC graphene nano-electromechanical system (NEMS) switch and nano-crossbar array electrostatic discharge (ESD) protection structure, and graphene ESD interconnects.
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Ilyushin, Pavel, Sergey Filippov, Aleksandr Kulikov, Konstantin Suslov, and Dmitriy Karamov. "Specific Features of Operation of Distributed Generation Facilities Based on Gas Reciprocating Units in Internal Power Systems of Industrial Entities." Machines 10, no. 8 (August 15, 2022): 693. http://dx.doi.org/10.3390/machines10080693.
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The creation of a decentralized low-carbon energy infrastructure is the main trend in the development of the electric power industry in many countries. Distributed generation facilities (DGs) based on gas reciprocating units (GRUs) are often built by industrial entities for the efficient utilization of secondary energy resources in order to minimize the environmental impact. Modern GRUs have some advantages, but they have design features that should be factored in when connecting them to the internal power systems of industrial entities. Incorrect consideration of possible operating conditions of GRU in their design can lead to their damage, excessive shutdowns, and disruptions in power supply to essential power consumers with significant damage and losses from undersupply of their products. Excessive shutdowns of GRUs are often caused by a non-selective choice of settings for relay protection devices or by load surges that exceed the allowable ones. With high availability factors, GRUs are disconnected five to eight times more often compared to large gas turbine and steam turbine power units. The large total power consumed by electric motors, as part of the load of an industrial entity, determines the nature and parameters of electromechanical transient processes during emergency disturbances. The presented analysis of issues facing real DG facilities relies on the acts of investigation into the causes of accidents. Calculations have shown that the action of the “Load Agreement Module” in the GRU excitation controller can provoke the occurrence of a voltage avalanche in the internal power system with a complete shutdown of the load. The paper presents recommendations on the choice of control algorithms and voltage settings for the GRU excitation controller. Technical solutions are given to prevent damage and excessive shutdowns of GRU in various operating conditions of the system, and to help ensure a reliable power supply to power consumers. The change in approaches to the design of DG facilities is substantiated in the light of their significant differences from other electric power facilities.
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DENISIEV, SERGEY A. "Improving the efficiency of integrated security systems at guarded facilities of the penal system." Vedomosti (Knowledge) of the Penal System 233, no. 10 (2021): 69–76. http://dx.doi.org/10.51522/2307-0382-2021-233-10-69-76.
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The article discusses topical issues of organizing the functioning of security and alarm systems, CCTV, access control and management systems, which are part of the integrated security system of a penal system facility. The purpose of the study is a substantive analysis of the problems arising in the process of equipping with technical means of security and supervision the control panel for technical means of protection, the premises of the duty-assistant of the head of the colony, the checkpoint for the passage of people, the restricted areas of a penal system facility. The subject of the article is the realized and possible integration links at the software and hardware levels between the security and alarm system, the CCTV system, the access control and management system. The methodological basis of the research was formed by the statistical method, analysis, synthesis, induction, system-structural and formal-logical methods. The conclusions on the need to equip the premises of the duty-assistant to the head of the colony with an automated workstation of the integrated security system have been substantiated; to equip the gates for access to the restricted area with proximity card readers to control an electromechanical lock. In addition, proposals were made on the need of mandatory informing the chief of the guard about the alarming situation arising in the biometric control and access control system at the checkpoint for the passage of people; on the feasibility of considering the possibility of verifying alarming events in the restricted area by installing dome cameras on observation towers. The practical significance of the work results lies in the fact that the conclusions we have declared can be used to reequip integrated security systems used at the penal system facilities. Key words: engineering and technical means of security and supervision, an integrated security system, a security and alarm system, a security television system, a control and access control system, the chief of the guard, an assistant to the head of the colony, security and fire control devices.
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Kosarev, Boris. "FERRORESONANCE OVERVOLTAGES IN ELECTRICAL INSTALLATIONS 6–220 kV: THEORY AND RESULTS OF EXPERIMENTAL STUDIES." Electrical and data processing facilities and systems 18, no. 3-4 (2022): 45–55. http://dx.doi.org/10.17122/1999-5458-2022-18-3-4-45-55.
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Relevance The article is devoted to the systematization and generalization of theoretical and experimental studies of ferroresonance overvoltages in electrical installations 6–220 kV. The need to study this issue is associated with the active introduction of distributed generation facilities into distribution networks, as well as medium and low voltage networks. In power districts with distributed generation facilities, the settings and operation algorithm of relay protection and automation devices differ from the traditional ones used in centralized power supply. The generation parameters and the nature of electromechanical transients also differ, which is caused by the low dynamic stability of generating plants based on synchronous generation and the use of network inverters with energy storage in electronic generation. Thus, due to significant differences in the parameters of the network operation mode with and without distributed generation objects, it is necessary to revise many well-known technical problems, including the issue of ferroresonant processes. Electrical installations of 6–220 kV were chosen as the object of research, since the concept of distributed generation does not imply backbone networks, and the maximum installed power of an individual facility is limited by 25 MW. Aim of Research Aim of research is to systematize and summarize the theoretical and experimental studies of ferroresonance overvoltages in electrical installations 6–220 kV. Research methods To study the circuit-mode conditions for the occurrence of ferroresonant processes in electrical installations of 6–220 kV, an analysis of foreign and domestic publications, standards was carried out, and the theoretical foundations of electrical engineering and the theory of nonlinear electrical circuits were used. Results The physical essence of the phenomenon of ferroresonance, the conditions for the occurrence of ferroresonant processes and measures to prevent them in medium and high voltage networks, experimental studies of ferroresonant processes are considered. The ferroresonant process consists in compensating the inductive and capacitive resistances in the oscillatory circuit with a saturated inductance core. There are various modes of ferroresonance, which are determined by the initial conditions: fundamental, subharmonic, aperiodic and chaotic. A prerequisite for the occurrence of a ferroresonant process is the power of the power source sufficient to saturate the inductance core. Non-linear inductance that can participate in the formation of an oscillatory circuit are voltage transformers, power transformers, shunt reactors. The capacity of the circuit can be a power line, a busbar system, a capacitor bank, shunt capacitors of switches. Hardware and operational measures to protect against ferroresonant processes in electrical installations are aimed at changing the capacitance or inductance of network elements that may participate in the formation of a ferroresonant oscillatory circuit, preventing the formation of such a circuit or reducing its quality factor. The results of experimental studies of ferroresonant processes do not contradict the guidelines for protection against resonant voltage increases in electrical installations. Keywords: ferroresonance overvoltages, distributed generation, ferroresonant process, electrical installation, busbar system, high-voltage switch, non-linear inductance
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Bannov, D. M. "ANALYSIS OF METHODS FOR DIAGNOSTICS BROKEN ROTOR BAR OF INDUCTION MOTOR." Electrical and data processing facilities and systems 17, no. 3-4 (2021): 5–23. http://dx.doi.org/10.17122/1999-5458-2021-17-3-4-5-23.
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Relevance Uninterrupted operation of industrial facilities, oil and gas sector, metallurgy, power generation and other industries directly depends on reliable operation of critical mechanisms driven by electromechanical converters, operated as a part of working complexes. Reliability of operation of such mechanisms depends on reliability of all elements that make up the technological process. Inductions motor with squirrel-cage rotor (including high-voltage motors) is one of the most common types of converters of electrical energy into mechanical energy. Its uninterrupted operation directly depends on the reliability of two main elements: stator and rotor. If the causes of induction motor failure due to stator causes (inter-turn, inter-phase and single-phase short circuits) are determined by the provided protections, the damage in the rotor circuit can be implicit and exist for a long time, violating the machine uptime. Also, most of the faults in the inductions motor, leading to an emergency shutdown of technological processes of working complexes have their own history of development. At the moment of occurrence and during the period when the defect does not affect the serviceability of the machine, but its operation becomes critically dangerous, because it is not possible to determine the presence of the defect. So, for example, the breakage of the short-circuited rotor core of a high-voltage induction motor manifests itself at the stage of exit to the air gap at the time of operation, with subsequent damage to the stator winding and the magnetic core. In this case, the existence of this defect took place within a certain period of time, sufficient for its detection by means of diagnostic devices. The article analyzes the currently developed systems for diagnosing the presence of a fault according to various parameters (temperature, noise, vibration, analysis of electrical values consumed) both in the stator and in the rotor. It is determined that the most promising and technically feasible are methods based on the analysis of stator currents. When studying the works in the direction of inductions motor diagnostics it was found that a significant proportion of failures of mechanisms operated in the working complexes due to failure of inductions motor occurs due to broken rotor bar. Aim of research Analyze the existing methods for diagnosing induction motors during operation. Research methods The article used general scientific research methods: the method of analysis of literary sources, the study and generalization of information, comparison, classification. Results The analysis of existing methods of continuous diagnostics of induction motors for internal electrical and mechanical damage is carried out. It has been determined that the most promising from the point of view of economic and technical feasibility are methods based on the analysis of currents consumed by the stator.
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Wilcox, Bryan, and Harry Dankowicz. "Limit-Switch Sensor Functionality Based on Discontinuity-Induced Nonlinearities." Journal of Computational and Nonlinear Dynamics 6, no. 3 (December 16, 2010). http://dx.doi.org/10.1115/1.4002686.
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Limit-switch sensors are input-output devices that switch operating state in reaction to the crossing of a threshold value of their input. These are used to monitor and control critical values of temperature, voltage, pressure, etc., in both consumer and industrial settings. This paper argues for exploiting nonsmooth fold bifurcations in the design of ultrafast and robust, resettable, electromechanical limit switches. Specifically, the discussion emphasizes the dramatic changes in system response associated with the onset of near-grazing, low-velocity contact in vibro-impacting systems. These include rapid transient dynamics away from a pre-grazing, periodic, steady-state trajectory following the onset of impacts and post-grazing steady-state trajectories with a distinctly different amplitude and frequency content. The results reported here include a review of an experimental and computational verification of the ultrafast transient growth rates that show a significant potential for dramatic improvement in sensor performance. Moreover, two novel candidate sensor designs are discussed that rely on the post-grazing response characteristics for device function. In the first instance, transduction of a change in the response periodicity following grazing in a mechanical device is detected in a coupled electromagnetic circuit. In the second instance, a snap-through post-grazing response forms the operating principle of a capacitively driven circuit protection device.
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ZAKHAKHATNOV, VIKTOR, and ALEKSANDR BELOV. "SIMULATION OF TRANSFORMER DIFFERENTIAL PROTECTION IN THE MATLAB ENVIRONMENT." Elektrotekhnologii i elektrooborudovanie v APK 1, no. 46 (2022). http://dx.doi.org/10.22314/2658-4859-2022-69-1-19-25.
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Currently, relay protection is based on microprocessor units, which have expanded functionality in comparison with traditional electromechanical means. For the correct operation of these devices, it is necessary to enter the actuation settings, which are calculated manually taking into account the characteristics of a particular power system. Modeling of relay protections in the MatLab environment allows reducing the role of the human factor and minimizing possible errors. (Research purpose) The research purpose is to develop a model of differential relay protection of the transformer in the MatLab Simulink environment. (Materials and methods) The article presents a model of a power system with a power two-winding transformer and differential relay protection with the functions of a current cut-off, differential protection with bias and blocking of the magnetization current surge. (Results and discussion) In the external short-circuit mode, the current protection does not acts, which indicates that the differential protection against external short circuits is detuned. In the short-circuit mode, current cut-off and protection with bias are triggered from the sides of the lower and higher voltages, which also indicates the adequacy of the model. Testing in the magnetization current surge showed that with the 0.15 detuning setpoint recommended by manufacturers of relay protection devices, the protection is blocked for more than 15 seconds, which is unacceptable in practice. The adequate operation of the relay protection is noted at a setpoint of 0.7. The dependence of the harmonic composition of the magnetization current surge on the switching moment on the transformer relative to the transition of the supply voltage through zero was revealed. (Conclusions) The developed model implements the functions of differential protection of the transformer, adequately reproduces all the processes of digital signal processing in microprocessor relay protection units, allows you to check the correctness of functioning in different modes and at different actuation settings.
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Pithe, Lokesh V., and Avinash M. Badadhe. "Automatic Electromechanical Single Plate Clutch with Overload Protection Roller Clutch for Machine Safety." International Journal of Engineering Sciences 14, no. 1 (2021). http://dx.doi.org/10.36224/ijes.140104.
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This paper summarizes the development of the automatic Electro-Mechanical single plate clutch with the overload protection roller clutch. The major challenges in a Single Plate Clutch automation are the clutch control, which is presently manual. It increases the manual effort and complication during its operation. Due to the complex structure and high cost, the clutch control system used in an advanced vehicle cannot use in economical Vehicles. This situation forces us to develop a Special electromechanical clutch that controls automatically. The rarely occurring overload on machines, create some malfunctioning in the System, which may damage its members. By using an overload protection clutch, such overload can neutralize. We develop an Automatic Engage-disengage Overload Protection Roller Clutch. The facility provided to change its torque carrying capacity make this roller clutch special. Thus the combination of the automated single-plate clutch and the overload protection clutch is a desirable one and also essential. After the market survey, it observed that there is no such combined system is available. If we install these two devices separately, it will require more space and cost, which is infeasible.
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Kashirin, D. E., and V. V. Pavlov. "ИССЛЕДОВАНИЕ ПРОЦЕССА САМОЗАПУСКА ЭЛЕКТРОДВИГАТЕЛЯ НА УЧЕБНОМ СТЕНДЕ." VESTNIK RIAZANSKOGO GOSUDARSTVENNOGO AGROTEHNOLOGICHESKOGO UNIVERSITETA IM. P.A. KOSTYCHEVA, no. 3(43) (November 27, 2019). http://dx.doi.org/10.36508/rsatu.2019.43.41395.
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В повышении эффективности процесса обучения значительную роль играет использование наглядных пособий и учебного оборудования, в том числе лабораторных испытательных стендов, работа с которыми дает возможность будущему специалисту закрепить на практике полученные знания. В статье дается описание лабораторного стенда, разработанного сотрудниками кафедры электроснабжения РГАТУ им. П.А. Костычева и предназначенного для обучения студентов по основной образовательной программе высшего образования направления подготовки Электроэнергетика и электротехника . Разработанный стенд предоставляет широкие возможности по изучению электромеханических защитных устройств вторичной коммутации приборов релейной защиты (РЗ) и автоматического повторного включения (АПВ), позволяет проводить исследование ряда явлений, происходящих в электросети при срабатывании данных устройств, в частности, явления самозапуска электродвигателей при восстановлении питающего напряжения после перерыва питания. Представлено краткое описание опытов, проводимых на данном стенде и наглядно раскрывающих принцип действия АПВ выключателей с электромагнитным приводом, совместную работу комплектов РЗ и АПВ при имитации устойчивых и неустойчивых коротких замыканий (КЗ). Отдельно рассмотрен опыт по определению влияния бестоковой паузы до АПВ на время самозапуска асинхронного электродвигателя. Результаты проведенного лабораторного исследования наглядно демонстрируют существование пропорциональной зависимости между величиной бестоковой паузы и временем самозапуска асинхронного электродвигателя, необходимым для восстановления его номинальной частоты вращения. В эксперименте помимо устройств, непосредственно входящих в состав испытательного стенда набора электромеханических реле, магнитных пускателей, переключателя и т.д., использован ряд дополнительных приборов и устройств: асинхронный электродвигатель, электросекундомер, однофазные трансформаторы, лабораторный автотрансформатор, мультиметр и др.In enhancing the effectiveness of the learning process, the use of visual aids and modern training equipment, including laboratory test benches, plays a significant role. Working with them enables the future specialist to consolidate the knowledge gained in practice. The article describes the laboratory stand, developed by the staff of the Department of Power Supply, Ryazan State Agrotechnological University Named after P.A. Kostychev, and intended to teach students on the basic educational program of higher education areas of training Power and electrical engineering. The developed stand provides ample opportunities for the study of electromechanical protective devices of secondary switching devices of relay protection and automatic reclosing, allows to study a number of phenomena occurring in the electrical network when these devices are triggered, in particular, the phenomenon of selfstarting electric motors voltage after a power break. A brief description of the experiments carried out at this stand and clearly revealing the principle of the operation of automatic reclosing switches with an electromagnetic drive, the joint operation of sets of relay protection and automatic reclosing in the simulation of stable and unstable short circuits is presented. Separately, the experience of determining the influence of a currentfree pause on the selfstarting time of an asynchronous motor is considered. The results of the laboratory research clearly demonstrate the existence of a proportional relationship between the value of the dead time and the selfstarting time of the asynchronous electric motor, which is necessary to restore its nominal speed. In the experiment, in addition to the devices that are directly part of the test bench a set of electromechanical relays, magnetic starters, switches, etc., a number of additional devices and devices were used: asynchronous electric motor, electric stopwatch, singlephase transformers, laboratory autotransformer, multimeter, etc.
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Zhang, He, Kangxu Huang, Zhicheng Zhang, Tao Xiang, and Liwei Quan. "Piezoelectric Energy Harvesting From Roadways Based on Pavement Compatible Package." Journal of Applied Mechanics 86, no. 9 (July 10, 2019). http://dx.doi.org/10.1115/1.4044140.
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Scavenging mechanical energy from the deformation of roadways using piezoelectric energy transformers has been intensively explored and exhibits a promising potential for engineering applications. We propose here a new packaging method that exploits MC nylon and epoxy resin as the main protective materials for the piezoelectric energy harvesting (PEH) device. Wheel tracking tests are performed, and an electromechanical model is developed to double evaluate the efficiency of the PEH device. Results indicate that reducing the embedded depth of the piezoelectric chips may enhance the output power of the PEH device. A simple scaling law is established to show that the normalized output power of the energy harvesting system relies on two combined parameters, i.e., the normalized electrical resistive load and normalized embedded depth. It suggests that the output power of the system may be maximized by properly selecting the geometrical, material, and circuit parameters in a combined manner. This strategy might also provide a useful guideline for optimization of piezoelectric energy harvesting system in practical roadway applications.
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Isakov, Alexander, Kimberly M. Murdaugh, William C. Burke, Sloan Zimmerman, Ellen Roche, Donal Holland, Jon I. Einarsson, and Conor J. Walsh. "A New Laparoscopic Morcellator Using an Actuated Wire Mesh and Bag." Journal of Medical Devices 8, no. 1 (January 15, 2014). http://dx.doi.org/10.1115/1.4026294.
Full textAbstract:
Laparoscopic morcellation is a technique used in gynecological surgeries such as hysterectomy and myomectomy to remove uteri and uterine fibroids (leiomyomas) through a small abdominal incision. Current morcellators use blades or bipolar energy to cut tissue into small pieces that are then removed through laparoscopic ports in a piecewise manner. These existing approaches have several limitations; (1) they are time consuming as the tissue must be manually moved over the devices during the cutting step and removal is piecewise, (2) they can lead to accidental damage to surrounding healthy tissue inside the body and (3) they do not provide safe containment of tissue during the morcellation process which can lead to seeding (spreading and regrowth) of benign or potentially cancerous tissue. This paper describes a laparoscopic morcellator that overcomes these limitations through a new design that is based on an enclosed, motor-actuated mesh that applies only an inward-directed cutting force to the tissue after it has been loaded into the protective mesh and bag. The deterministic design approach that led to this concept is presented along with the detailed electromechanical design. The prototype is tested on soft vegetables and an animal model to demonstrate successful morcellation and how the device would be compatible with current clinical practice. Results show that the time required to morcellate with the new device for a set of tests on animal tissue is relatively uniform across samples with widely varying parameters. Including tissue manipulation and extraction time, the new device is shown to have an improvement in terms of speed over current morcellators. The mean time for cutting animal tissue ranging from 100 g to 360 g was 30 s with small variations due to initial conditions. The time for cutting is expected to remain approximately constant as tissue size increases. There is also minimal risk of the protective bag ripping due to the inward-cutting action of the mesh, thereby potentially significantly reducing the risk of seeding during clinical procedures; thus, further increasing patient safety. Finally, this design may be applicable to other procedures involving removal of tissue in nongynecologic surgeries, such as full or partial kidney or spleen removal.
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Li, Xiaodong, Veit Grosse, Dongbin Song, Wenjiang Yang, and Rafael Macian-Juan. "Electromechanical behaviour of REBCO coated conductor toroidal field coils for ultra-high-field magnetic-confinement plasma devices." Journal of Physics D: Applied Physics, December 7, 2022. http://dx.doi.org/10.1088/1361-6463/aca988.
Full textAbstract:
Abstract The development of rare-earth barium copper oxide (REBCO) coated conductors with an extremely high critical current density under ultra-high fields opens up a high-field path towards large-scale fusion. The latest technology has inspired cable-in-conduit conductors (CICC) such as conductor on round core (CORC) wires, twisted stacked tape conductor (TSTC) cables and Rutherford cables with outstanding current-carrying capacities. In order to realise an inductance balance and decrease magnetic diffusion, these cables have been twisted or folded to a certain extent, thus breaking the mechanical behaviour of the ceramic superconductor and limiting their potential for ultra-high-field applications. One possible solution is to employ a non-twisted cable, which offers maximum protection of its mechanical properties and enables a parallel orientation of the toroidal field vector to the surface of REBCO coated conductors. However, the applied physics community’s attitude towards using non-twisted, parallel REBCO stacked-tape cables is one of scepticism, the main argument being that the nonlinear E-J behaviour associated with screening current in the parallel stack might lead to a field distortion and reduce the performance of superconductivity. Recent analyses have demonstrated that the effect of screening current decreases significantly owing to a wavelike magnetic field distribution along the cable. The authors obtained similar results using H-formulation and T-A formulation based finite element methods and demonstrated that the non-twisted cable may be feasible for DC current transmission toroidal field coils in magnetic-confinement devices. Furthermore, the electromechanical behaviour of toroidal field coils has been evaluated via the Maxwell stress, solved by using an A-V formulation. It was discovered that the stress generated by the toroidal field coils is within the stress tolerance of the REBCO coated conductor, something which is of great significance in promoting the application of REBCO coated conductors for ultra-high-field magnetic-confinement plasma devices.
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El-Bayeh, Claude Ziad, Mohamed Zellagui, and Brahim Brahmi. "A Novel Fully Controllable Rotary Switch for Electrical Installation in Buildings." ENERGY, ENVIRONMENT & STORAGE 1, no. 3 (November 26, 2021). http://dx.doi.org/10.52924/dkma3371.
Full textAbstract:
In an electrical installation in buildings, electromechanical switches are mostly used to turn on and off a load. However, sometimes there are two or more switches in the same circuit intended to control the same load. Thus, a conflict can happen between multi-users who are trying to overtake the control of the load (such as turning it on or off). To solve the problem, this paper proposes a novel switch called “Fully Controllable Rotary Switch” (FCRS) in which it can fully control not only the load but also other switches by blocking them or giving them limited or full access over the electrical circuit and the loads. For validation purposes, the utilization of FCRS in buildings is compared to the traditional switches under the same functionality and conditions. Results show that FCRS has the ability to control many electrical loads simultaneously, control other switches in the circuit, increase the satisfaction, security, and privacy of the users. Finally, it reduces the conflict between multi-users and the investment cost by avoiding installing additional switches and protection devices.
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El-Bayeh, Claude Ziad, Mohamed Zellagui, and Brahim Brahmi. "A NOVEL FULLY CONTROLLABLE ROTARY SWITCH FOR ELECTRICAL INSTALLATION IN BUILDINGS." ENERGY, ENVIRONMENT & STORAGE 1, no. 3 (October 13, 2021). http://dx.doi.org/10.52924/zurr2598.
Full textAbstract:
In an electrical installation in buildings, electromechanical switches are mostly used to turn on and off a load. However, sometimes there are two or more switches in the same circuit intended to control the same load. Thus, a conflict can happen between multi-users who are trying to overtake the control of the load (such as turning it on or off). To solve the problem, this paper proposes a novel switch called “Fully Controllable Rotary Switch” (FCRS) in which it can fully control not only the load but also other switches by blocking them or giving them limited or full access over the electrical circuit and the loads. For validation purposes, the utilization of FCRS in buildings is compared to the traditional switches under the same functionality and conditions. Results show that FCRS has the ability to control many electrical loads simultaneously, control other switches in the circuit, increase the satisfaction, security, and privacy of the users. Finally, it reduces the conflict between multi-users and the investment cost by avoiding installing additional switches and protection devices.
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Fasoro, Abiodun A., Manoj Mittal, Dan O. Popa, Dereje A. Agonafer, and Harry E. Stephanou. "Design for Reliability Applied to Packaging of a MOEMS Switch." Journal of Electronic Packaging 130, no. 4 (November 17, 2008). http://dx.doi.org/10.1115/1.2993142.
Full textAbstract:
Microelectromechanical systems (MEMSs) consist of moving mechanical microparts often integrated with electronics and optics that may be used for sensing or actuating purposes. MEMS and micro-opto-electromechanical system (MOEMS) packaging requirements vary widely with application, but they generally involve protecting the device from the damaging effects of the environment, such as moisture and dust. Reliability is often not considered as a design factor during product development. Rather, reliability is assessed using life tests, accelerated tests, and other techniques after a product has completed its development cycle. The goal of design for reliability (DfR) is to be proactive by introducing reliability early in product development so that concerns are identified and assessed at every stage, from the conception to obsolescence. In this paper, we present a framework for applying DfR principles to MOEMS packaging. Such an approach is desirable for several reasons. First, it reduces the cost and time for product development by departing from the “build-test-rebuild” approach. Second, it provides better understanding of the process input-output relationships, so the practitioner is better able to make informed design decisions. Lastly, this can lead to enhanced product performance, reliability, and reduced cost. To demonstrate the use of DfR in MOEMS packaging, we present a case study involving carrier level packaging of a MOEMS switch. The reliability requirements for this device are stringent, namely, a shelf life of 25years or more, requiring hermetic sealing through the use of metal seals and no organic compounds inside the package. Simulation and experiments are used systematically in order to guide the package design and process windows, ensuring that the device passes MIL-STD reliability tests. The packaging processes include fluxless die-to-carrier attachment, optical fiber-to-carrier attachment, and hermetic sealing. Results show that our packaging approach can determine adequate process windows using only a small number of reliability experiments.