Search

Tissue paper is deep-rooted in our daily life because of its different types of products that allow various applications. Tissue paper is a low grammage paper that is mainly characterized by softness, tensile strength, liquid absorption, and elasticity. These characteristics are essential when producing products such as toilet paper, kitchen rolls, hand towels, napkins, and facials. The tissue paper production involves two stages: formation of the tissue paper sheet itself and its converting into different finished products. Converting is characterized by several operations, namely: unwinding, winding, embossing, lamination, perforation, cutting, packaging, and palletizing. The most impacting operation is the embossing, which consists of marking a pattern on the paper sheet by applying pressure, with the intent to produce papers more aesthetically pleasing to the final consumer and/or a way to identify a particular brand. Also, it affects final properties, increasing the liquid absorption capacity and bulk but reducing softness and tensile strength. Converting is complex and has a huge impact on the finished products properties. In this review, the authors explored the different steps of converting and how they impact the different properties of finished tissue products. [ABSTRACT FROM AUTHOR]

The paper overviews modern axial-flux permanent-magnet synchronous electric motor designs with a particular emphasis on the double-sided TORUS design with a slotted stator core. The concentrated and distributed stator windings with short end-winding lengths are presented. Differently shaped rotor permanent magnets are discussed. They are either shaped in different ways, segmented and glued together, magnetized according to the Halbach array or of a variable thickness. A comparison is made between the market available motors, according to their technical properties. [ABSTRACT FROM AUTHOR]

This paper reports a new strand wire winding method in a solenoidal coil with limited geometry that enables good impedance matching. In the proposed method strand wires are wound layer-by-layer on top of each other allowing one to set equivalent inductance and resistance of the coil to desired values while obtaining dense magnetic flux and high current carrying capacity. As a proof-of-concept demonstration, simple model setups were constructed with solenoidal coils composed of copper wire strands wound according to the proposed method, and a plastic pipe. The measurements were repeated with a metal shell placed inside the coil to model a complete heating system. System inductance and resistance were measured at two different frequencies. The results show that with the new winding method it is possible to increase a coil's turn number and the number of strand layers composed by the coil. Also, adding and removing strand layers in the proposed coil architectures enable inductance and resistance values to decrease and increase, respectively, in a controlled way. To understand changes of system parameters, simulations were also performed. The calculated inductance and resistance values in the simulations agree well with the measurement results and magnetic flux distribution created in the system demonstrates the changes. [ABSTRACT FROM AUTHOR]

We study a model for the entanglement of a two-dimensional reflecting Brownian motion in a bounded region divided into two halves by a wall with three or more small windows. We map the Brownian motion into a Markov Chain on the fundamental groupoid of the region. We quantify entanglement of the path with the length of the appropriate element in this groupoid. Our main results are a law of large numbers and a central limit theorem for this quantity. The constants appearing in the limit theorems are expressed in terms of a coupled system of quadratic equations. [ABSTRACT FROM AUTHOR]

Hairiness is an important quality parameter of yarn after winding process. It affects not only the quality of yarn, but also the productivity of the warping, weaving, knitting machines as well as the quality of produced fabrics. Hairiness is influenced by the factors of raw materials, technology and equipment at all stages of yarn production. This article presents the results of experimental research on the simultaneous influence of four typical winding parameters, including: Winding speed (Z1), the load on the friction discs of the yarn tensioner (Z2), the distance between the bobbin and the yarn guide (Z3) and the pressure of package on the grooved drum (Z4) to the increasing percentage of the hairiness of the yarns after winding compared to that before winding. Yarn hairiness was measured by Uster tester 5. By using the second-order orthogonal experimental planning, together with the support of Excel 2019 and Design Expert 11 software, an experimental matrix and mathematical models describing the relationship between the four winding parameters and increasing percentage of the hairiness of three types of yarn (carded Ne 31/1 CVCD, combed Ne 30/1 CVCM, combed Ne 30/1 COCM) are established. The research result is the scientific basis for selecting the optimal winding parameters in order to achieve the required increase in hairiness of the yarn after winding or predict hairiness increase of the yarns before winding. [ABSTRACT FROM AUTHOR]

Alternating current (AC) copper losses in motors increase with carrier frequency of the pulse width modulation (PWM) and are further increased by leakage flux of the permanent magnet. Therefore, AC copper losses increase with motor speed. Conventional techniques for reducing AC copper losses tend to increase other losses. In this paper, AC copper loss was reduced by wrapping a magnetic tape made of a magnetic composite material around the winding. This method controlled the flux path through the winding. Magnetic composite materials are mixtures of magnetic powders and liquid resins whose magnetic properties can be manipulated by changing the combination and other factors. When Fe–Si–Al magnetic tape was wrapped around the winding, the AC copper loss was reduced by 40%. The loss was further reduced by optimizing the magnetic properties of the magnetic composite material. The AC copper loss was maximally reduced when the specific permeability was 100 and the saturation flux density was 1.6. Magnetic tapes composed of magnetic composite materials with high saturation flux density and specific permeability reduce the AC copper losses without increasing other losses in the motor. [ABSTRACT FROM AUTHOR]

Relevance of the work is related to the fact that currently the technological processes of exploration, extraction, transportation of geo-resources in the oil, mining, coal, chemical and other industries are subject to a high level of mechanization and automation involving electric machines. The reliability and trouble-free operation of these machines depend on the state of the winding insulation, the role of which is played by the insulation of the windings of electric motors. Reliability indicators of this element of the windings are laid in the process of their production. At the same time, a significant contribution to the mentioned indicators is made by the technological operation of impregnation. The probability of hiding defects in the insulation of the windings, thermal properties of electric motors, moisture resistance and solidity of the windings depend on how well this operation is carried out. Therefore, the improvement of impregnation and increase of its efficiency are very topical. The purpose of the work is to create a mathematical model of the technological operation of impregnation with the use of electrostatic charging of the impregnating composition jet; to show that it is possible to reduce the level of induced voltage used for electrostatic charging of the impregnating composition jet by strengthening the electric field in the nozzle area, from which the frontal parts of the winding are watered with impregnating composition, by giving the nozzle a certain shape. Methods. When creating a mathematical model, classical methods of solving differential equations describing electromagnetic fields were used, and experimental studies made it possible to establish the adequacy of the created model. Results. The results of modeling and research of a new technology of impregnation of windings of electric machines with an electrostatically charged jet of impregnating composition are presented. A mathematical model was developed linking the field gain at the top of an ellipsoid nozzle with its geometric parameters. The experimental verification of the obtained model was carried out and the adequacy of the model to the experimental results was shown. The data of practical application of the obtained model on real factory installations are presented, showing the real possibility of reducing the voltage level at the nozzle and the effectiveness of the proposed impregnation of the windings. The advantages of the proposed technology are shown in comparison with typical impregnation technologies based on the data obtained in real production. The proposed technology will significantly reduce the likelihood of factory defects due to winding circuits in the windings, will increase the reliability of manufactured electric motors in the process.

• We study the effect of skin and proximity effects on the ac impedance of windings. • The effect of temperature and frequency in transformer windings is studied. • We propose an analytical method to separate skin and proximity contributions. • Experimental results and FEA simulations are used to validate the proposed method. • Presented results are based on a single-phase transformer. Eddy current effects, which include skin and proximity effects, are usually associated only with frequency, but they are also affected by temperature. This paper analyzes the effect of both, temperature and frequency on skin and proximity effects in transformer windings. When analyzing transformer windings, despite the existence of powerful finite element analysis (FEA) modules, they return the total contribution of eddy current effects and do not separate the contributions of skin and proximity effects. This paper proposes an analytical method to determine the contribution of both effects to the AC winding resistance and leakage inductance based on the orthogonality of the skin and proximity effects. This method is based on the exact solution of the skin effect for an isolated round conductor combined with Dowell's solution of the proximity effect. Presented experimental results and FEA simulations based on a single-phase transformer have determined the accuracy of the proposed method, which allows accurate prediction of the temperature and frequency behavior of the winding resistance and leakage inductance. [ABSTRACT FROM AUTHOR]

Additive manufacturing is a promising and resource-efficient construction method, applying material only where needed. Demand for these processes in construction is growing, but research into their use in timber construction is limited. The 3DWoodWind project explores additive application methods using thin wood veneer strips. Robotic winding processes can be used to develop wood-based hollow parts with minimal material input and optimised structural properties. This paper presents a modular building system of robotically wound column and slab components, including a brief description of the structural design and material system, with a focus on the manufacturing process. It covers in detail robotic fabrication, customised end-effector design, formwork system development, computational design methods, and the integration of a fully automated adhesive application system. A full-scale prototype roof structure demonstrates the manufacturing process and reusability concept in various architectural applications. The paper concludes by discussing the building system's potential and areas for further research. • Additive application methods of wood veneer as a sustainable alternative to synthetic fibres. • Three-dimensional robotic winding processes for material-efficient lightweight components. • Production of a modular column and ceiling system for large-scale applications. • Computational design methods for filament layup and fibre orientation. • Highly automated robotic fabrication technique with customised end-effector design. [ABSTRACT FROM AUTHOR]

A person’s body temperature is an important indicator of their health status. A deviation of that temperature by just 2 °C already has or can lead to serious consequences, such as fever or hypothermia. Hence, the development of a temperature-sensing and heatable yarn is an important step toward enabling and improving the monitoring and regulation of a person’s body temperature. This technology offers benefits to several industries, such as health care and sports. This paper focuses on the characterization and development of a hybrid yarn, which can measure and visualize temperature changes through a thermoresistive and thermochromic effect. Moreover, the yarn is able to serve as a flexible heating element by connecting to a power source. The structure of the yarn is designed in three layers. Each layer and component ensures the functionality and flexibility of the yarn and additional compatibility with further processing steps. A flexible stainless steel core was used as the heat-sensitive and heat-conducting material. The layer of polyester wrapped around the stainless steel yarn improves the wearing comfort and serves as substrate material for the thermochromic coating. The resulting hybrid yarn has a reproducible sensory function and changes its resistance by 0.15 Ω between 20 and 60 °C for a length of 30 cm. In addition, the yarn has a uniform and reproducible heating power, so that temperature steps can be achieved at a defined length by selecting certain voltages. The thermochromic color change is clearly visible between 28 and 29 °C. Due to its textile structure, the hybrid sensory and actuating yarn can easily be incorporated into a woven fabric or into a textile by means of joining technology sewing.

The elimination of harmonic components of the magnetic motive force (MMF) waveform improves the performance of induction motors. The non-sinusoidal MMF waveform creates harmonic components. One of the effects of these components is to increase core losses, noise, and vibration while reducing the efficiency of induction motors. In this paper, to eliminate the harmonic components of the MMF waveform, a novel winding design for the stator of the induction motors is presented. Then, the novel winding design is compared to the conventional one. The effects of the new winding have been investigated to improve the performance of the induction motor. Also, the designed stator winding in ANSYS MAXWELL software was simulated and its magnetic parameters were evaluated. Finally, practical experiments have been performed on two similar 3-phase motors of 380 V, 50 Hz, 180 W, and 2-pole. The obtained simulation and experimental results illustrate the superiority of the novel winding over the conventional one. [ABSTRACT FROM AUTHOR]

The operating condition and structural state of the converter transformer are closely related to vibration. Abundant harmonics aggravate the vibration of windings and iron cores, resulting in frequent mechanical structural failures, which seriously affect the stable operation of the power system. Traditional research mainly focuses on the vibration of AC transformers without harmonics and there is no in-depth discussion of the vibration mechanism and the numerical calculation model of windings and iron cores under harmonics. In addition, the influence of harmonics, winding connection method and other factors on the vibration characteristics are not clear. Therefore, this paper analyzes the voltage and current harmonic components and contents, establishes a harmonic-vibration numerical model and compares the vibration time-frequency characteristics with or without harmonics and different valve side winding connections through vibration measurement experiments. Finally, a combined simulation analysis reveals the contribution of the windings and core to the tank. The results show that the tank vibration amplitude and dominant frequency will increase under harmonica and the valve side current will affect the dominant frequency. Among these results, when there are harmonics, the amplitude increases by three times, the vibration dominant frequency changes from 100 Hz to 400 Hz and the frequency spectrum widens to 2000 Hz. In particular, the contribution of the winding vibration under the harmonic current will exceed the iron core. The research results reveal the influence of converter transformer harmonics on vibration, which can provide a theoretical basis for numerical calculation of vibration and monitoring of operating conditions and guide the design of structural vibration reduction to reduce mechanical failures caused by vibration. [ABSTRACT FROM AUTHOR]

Roll‐to‐Roll manufacturing aims at scaling ultraviolet‐ and thermally cured nanoimprint lithography (UV‐NIL, T‐NIL) to commercial production speeds and volumes. Winding is the only convenient way of storing large quantities of nanoimprinted webs as they await unwinding in sequential R2R processes with distinct transport speeds. At production speeds, the imprinted resin is still chemically evolving when the imprinted web enters the winder, through a phenomenon called dark curing. The viscoelastic resin at various curing stages deforms under the contact pressure due to winding. This study is concerned with the impact of the contact pressure on the imprinted peak heights and potentially the functionality of the nanoimprinted surface. We develop a multiscale numerical model of the winding of the imprinted web. First the evolving properties of the resin through time are characterized, combining the effect of dark curing and viscoelasticity on the time‐dependent properties. Second, a finite element model of the imprinted web uses the resin mechanical properties to determine the effective properties of the imprinted web. Finally, the winding model determines the pressure and resulting strain of the imprints in the wound roll. The surface creep is quantified. This prediction will establish how and how long the imprinted materials should be wound. [ABSTRACT FROM AUTHOR]

Introduction. With the adoption of standards to reduce losses in transformers it is necessary to change the design of transformers that remain unchanged. Further energy saving is possible with the use of non-traditional technical solutions for the improvement of transformers. Problem. In order to reduce idle losses, the curved magnetic circuits of power transformers are carried out in the form of low-volume circuits. Windings are injected into assembled magnetic conductors by shuttle machines. The shuttle of windings provides technological gaps in winding windows, which results in an increase in size, metal capacity and losses. Goal. Rationale for transformer performance improvement by excluding process gaps in winding windows. Methodology. The definition of the change in transformer indicators is performed using optimization functions of the dimensionless indicators of the technological level. The adequacy of the functions is confirmed by the calculation of the mass of the electromagnetic system and the losses of the transformer. The figures of the compact analogue are calculated from the named serial analogue. Results. The result is a reduction in mass and a loss in the compactness of the transformer. Originality. The improvement of the indicators and the simplification of the winding technology are provided by a change in the design of insulating frames of winding coils. Winding on the rods is ensured by rotating the outer part of the composite insulating frame. Practical significance. Replacement the design of the windings of transformer with power of 40 kVA of 1000 V voltage class with a spatially twisted, small-dimensional magnetic conductor on a compact analogue leads to a reduction in mass and overall dimensions by 15 % and (17-18) %. Efficiency increases by 0.3 %. References 14, tables 2, figures 4. [ABSTRACT FROM AUTHOR]

To achieve a carbon-neutral sustainable future, the transportation sector is experiencing quick electrification, as more and more vehicles are driven by electric motors. Electric motors are designing more and more powerful and thus pose a great increasing challenge for thermal management. In this paper, an innovative experimental study on oil spray for end winding thermal management were presented. The experimental results indicated that the oil spray cooling significantly decrease the temperature of the winding. With higher oil temperature and flow rate, better cooling performance and better temperature uniformity were achieved both for teeth and slot winding. Meanwhile, a heat transfer performance prediction model based on a fully connected artificial neural network (ANN) was developed to correlate oil spray. The model used Reynolds number and Prandtl number as inputs, and the number of neurons in hidden layer was optimized to 8. The model accurately predicts the heat transfer performance of oil spray with a correlation coefficient of 0.93. The paper is expected to be a good reference for the oil spray engineering application in e-motor cooling.

Background. The actual problem in the development of new types of aviation products is the creation of angular displacement sensors with high stability, measurement accuracy and reliability. Materials and methods. The methods of integral and differential calculus, the theory of electric circuits and electromagnetic field were used to solve the problems. The computer-aided design system KOMPAS was used in the design of sensor structures. Results. As a result of this work, a three-channel angular displacement sensor and two versions of the secondary converter have been developed. The substitution diagram of transformer angular displacement sensor on the basis of which the expression defining dependence of output EMF value on angular displacement of the sensor rotor is obtained.

The ITER in-vessel Vertical Stabilization (VS) coils, composed by the upper and lower VS coils, are designed to provide fast vertical stabilization of the plasma through a fast-current noise profile to compensate small plasma oscillations and to recover vertical displacement events. The VS coils are made by 4 continuous turns of Mineral Insulated Conductor (MIC) joined by Inconel ® 625 welded brackets, installed on rails on the inner wall of ITER Vacuum Vessel (VV). Thus, the coil turns winding/forming and the entire coils assembly have to be performed inside ITER VV, forcing the assembly procedure and tooling design to cope with the very limited space and strict constraints of ITER VV environment. The proposed procedure foresees that MIC conductor is un-spooled in the Neutral Beam (NB) port area and inserted into the ITER VV through a NB equatorial port, then a set of tooling is installed on a reinforced staging platform to wind, form and seal the conductor turns and finally to weld brackets under pre-compression. For this purpose, the tooling design including the reinforcement staging has been developed to meet the required tooling function, configuration optimization, assembly procedure and environmental constraints. The dedicated tools to be used for the assembly procedure of the VS coils are categorized into ex-vessel tools for unspooling and cleaning, in-vessel tools for winding and bump forming, bracket assembly tools for pre-compression and welding, termination and sealing tools, ancillary lifting tools and reinforcement staging platforms. This paper provides the overall assembly procedure and tooling development for the in-situ winding of VS coils. [ABSTRACT FROM AUTHOR]

The large thickness COPV is designed by netting theory and the finite element simulation method, but the actual performance is low and the cylinder performance still cannot be improved after increasing the thickness of the composite winding layer. This paper analyzes the reasons for this and puts forward a feasible solution: without changing the thickness of the winding layer, the performance of COPV can be effectively increased by increasing the proportion of annular winding fiber. This method has been verified by tests and is supported by theory.

Despite major progress in the design of power transformers, the Achilles’ heel remains the insulation system, which is affected by various parameters including moisture, heat, and vibrations. These important machines require extreme reliability to guarantee electricity distribution to end users. In this contribution, a fiber optic sensor (FOS), consisting of a Fabry–Perot cavity made up of two identical fiber Bragg gratings (FBGs), is proposed, to monitor the temperature and vibration of power transformer windings. A phase shifted gratings recoated sensor, with multilayers of polyimide films, is used to monitor the moisture content in oil. The feasibility is investigated using an experimental laboratory transformer model, especially fabricated for this application. The moisture contents are well correlated with those measured by a Karl Fisher titrator, while the values of temperature compare well with those recorded from thermocouples. It is also shown that the sensors can be used to concurrently detect vibration, as assessed by sensitivity to the loading current. The possibility of dynamically measuring humidity, vibrations, and temperatures right next to the winding, appears to be a new insight that was previously unavailable. This approach, with its triple ability, can help to reduce the required number of sensors and therefore simplify the wiring layout.

Analysis of methods for determining the hardness of the winding shows that all existing methods require a lot of labor and time. When measuring the layer-by-layer hardness, the known methods do not allow obtaining continuous values, and in the case of measuring the hardness of packages of complex shape (conical bobbins, cops, spinning cobs, etc.), it requires a calculation using cumbersome formulas. In this case, the main difficulties arise in determining the volume of the layers of the winding, which in the general case have a complex configuration, and due to defects in the winding may have an irregular shape. Obviously, the described technique is rather cumbersome, and a lot of measurements and calculations are required to obtain a graph of the change in the winding hardness along the package radius. The construction of a graph of the change in hardness along the generatrix using a special device is generally problematic, since placement of more than three sources on the device is impossible due to the size of the meters, and the construction of the curve by three points cannot be considered satisfactory. Winding hardness is one of the most important parameters, on which many technological properties of the package depend. Indeed, with an increase in the hardness of the winding, the amount of material in the same volume increases, which makes it possible to replace packages less often, both on the machine that forms them, and at the subsequent transition. As a result, the equipment useful time increases. It was found that the hardness of the winding is closely related to its rigidity, and hence to the stability during transportation. The hardness of the winding affects the permeability of the package when it is treated with solutions. In this case, a huge role is played not only by the average value of the hardness, but also by its distribution over the layers. [ABSTRACT FROM AUTHOR]

Currently, industrial winding processes are often optimized by trial and error. A digital twin of winding processes could be helpful in order to assist industry to optimize the winding processes. Formulating the kinematic equations that form the basis of such a simulation of the winding process is straightforward in principle. However, a major challenge is to model the increase of the package diameter as a function of time or length of wound up yarn, respectively. In this paper, a kinematic model for the winding process is first outlined. The focus of the paper is the description of a workflow in order to find a model for the package diameter increase dependent on the wound yarn length. For that purpose, a new image analysis method is presented to derive the general class of the model function for the diameter increase. Then, the measurement results of a series of experiments are analyzed to find a parameterization of the model function. Here, the input process parameters winding tension, cradle pressure, winding speed, and traverse ratio are varied at two levels. Finally, the linear regression model for the package diameter increase is presented. [ABSTRACT FROM AUTHOR]

The demand for products made of fiber‐reinforced polymer composites (FRPC) is constantly growing. These lightweight products are characterized by high stiffness, high tensile strength, and high service life. FRPC processes that employ thermoset‐impregnated continuous rovings are easily automated and provide the products with the highest unidirectional tensile strength. A critical disadvantage of continuous fiber‐reinforced polymers is caused by relatively high production costs. Among others, three main factors contribute to these production costs: (1) material costs, especially when carbon fibers are used, (2) costs for manufacturing semi‐finished products, such as textiles or preimpregnated fabrics, and (3) costs for waste occurring along the entire chain of process steps. In this context, one group of processes shows outstanding characteristics: processes in which rovings are in situ impregnated with a thermoset resin and then directly processed. Wet filament winding and pultrusion are the most popular but not the only representatives of this group. For all these processes, in situ impregnation is the key element, and various technologies have been developed for this purpose, each with its own unique fluid‐mechanical effects on rovings. A fundamental understanding of these effects is crucial to achieve products of the utmost quality. The paper at hand provides an overview of manufacturing processes that employ in situ impregnation of continuous rovings, specifically focusing on impregnation technologies. On this basis, phenomenological models describing the effects on the rovings during processing (impregnation, tension, and spreading) are reviewed. [ABSTRACT FROM AUTHOR]

An accurate prediction of modal characteristics of motor stator is essential in order to design a low vibration motor and to operate it quietly. Scholars have done a lot of research on the modal analysis of stator core and winding. However, there are few papers for the 0th-order mode shape and frequency of the stator system. This paper aims to propose a new stator system analysis model, which can effectively analyze the 0th-order mode and improve the model calculation efficiency. Firstly, the modal of stator core and stator core-winding system were analyzed theoretically. Secondly, four stator system finite element analysis models were established. The modal analysis of the stator core and stator core-winding system were carried out using the four models. The validity and computational efficiency of the four models of the stator core and stator core-winding system were compared. A new stator system analysis model was proposed. Thirdly, the modal tests of the stator core and stator core-winding system were carried out by hammering method, and the validity of the finite element analysis model was verified. Compared with the traditional model, the newly proposed model can analyze the 0th-order mode more effectively and improve the computational efficiency.

The total leakage reactance of the transformer with concentric cylindrical windings depends on the thickness of the coils and the gap between them. Existing methods do not allow measuring reactance of scattering for each winding of a transformer separately, therefore, for simplicity they are often considered equal to each other. In fact, in relation to the case under consideration, they are essentially not equal. In fact, the calculation of the flux linkage of the external winding shows that its reactive scattering resistance is greater than the total scattering resistance of both windings. Two circumstances follow from this. First, the internal winding of the transformer absorbs magnetic flux to a greater extent than it scatters (scatters its magnetic flux, absorbs from the external winding). The second is that its (equivalent) scattering reactance is capacitive. The purpose of the study is to justify the possibility of experimental determination of the scattering reactance for each transformer winding separately. The relevance of the work is due to the widespread distribution of transformers. The dissipation reactance of each winding of the transformer individually can be determined by at least three experimental methods that give satisfactory agreement between the results. An almost paradoxical result is the capacitive nature of the scattering resistance of the inner winding of the transformer obtained only for concentric cylindrical windings. It should not be generalized to other types of windings. The presented experimental methods are not tied to the nature of the reactivity of scattering resistances. They are universal and can be used with any type of windings. The results obtained are recommended for use in the design and study of transformers.

The paper suggests a general approach to creating hightech energy-efficient electrical systems based on low-speed synchronous magnetoelectric machines. The task is to optimize the magnetic system according to the criterion of specific net power while ensuring a minimum mass of the active materials used. The optimal mass-dimensional relations for the magnetic system of a linear magnetoelectric drive are given, which determine the maximum developed electromagnetic force. In addition, the paper presents a classification of starting and operational characteristics of synchronous magnetoelectric machines as part of electrical complexes.

This paper conducted an experimental study of reduced models of a main gas pipeline for avalanche damage considering operational conditions. Two options were considered as a method of avalanche damage prevention: single steel rings at the crack edges and steel winding with a winding pitch of 0.25 m. For the tension force, 5% of the steel wire breaking force was taken, which was equal to 1 mm. The ambient environment was simulated by a climatic chamber, where two options of temperature loads were considered: +20 °C and -10 °C. It was found that reinforcement with single rings of pipeline models under conditions of positive (+20 °C) and negative (-10 °C) temperatures showed that the crack opening width in the ring direction decreased 1.63 times and 1.9 times, accordingly. The crack length (longitudinal direction) decreased 2.18 times and 2.45 times, accordingly. The reinforcement of the pipeline models with prestressed wire winding on the crack propagation under conditions of positive (+20 °C) and negative (-10 °C) temperatures showed that the width of the crack opening in the ring direction decreased 1.5 times and 1.46 times, accordingly. The crack length (longitudinal direction) decreased 1.4 times and 1.44 times accordingly, which is a positive moment in addressing the issue of the localisation and stoppage of a crack fracture in main gas pipelines. Simultaneously, the analysis of the prestressed pipelines model test results on crack fracture propagation showed that single rings are more effective, which decreased the crack opening width by 1.1 times and the crack length up to 1.5. Therefore, the experimental results obtained positively complement the available methods of crack localisation in main gas pipelines, which can be used by engineers and research communities when designing or reinforcing existing operating main steel gas pipelines.

In order to prevent tipping paper from winding on gluing roller at machine start/stop stage, an air blowing device was designed for ZJ116B cigarette maker. An IPC system was used to control the on/off of air supply, the air jets installed on the upper and lower sides of tipping paper blew the tipping paper at both sides during the start/stop stage to keep the tipping paper at a tensioned state and prevent it from falling on the gluing roller. The modified ZJ116B cigarette maker was tested on slim cigarettes of brand "Mount Tai (White General)" in Qingdao Cigarette Factory. The results showed that the frequency of tipping paper winding on gluing roller reduced from 7.4 times/shift to 0, and the time for artificial gluing roller cleaning decreased by 74 min/shift. This method could be popularized and applied on ZJ17D, ZJ112A and other cigarette makers. [ABSTRACT FROM AUTHOR]

Since the "big five," the proposed large-scale planning and construction system of substations has seen rapid development, providing enough energy for people while also causing a series of problems, such as a gradual increase in radiation and magnetic fields. It not conducive to artificial operation, such as in case of frequent high-voltage electrical equipment failure, which again negatively influences the whole electric power system operation. Especially, the electrical failure of high-voltage equipment, if not found and solved in time, could cause a major power accident, bring economic losses to the power company, and even threatening the life safety of staff. None of these risks can be ignored. Based on this, in order to reduce the risk of substation accidents and to promptly discover and solve the problem of electrical failure in high-voltage equipment, this paper studies the substation in BX area as an example, by using the frequency response method, such as a low impedance of transformer for the winding deformation test. The winding has carried out with the handover testing and hoisting cover inspection With the collapse of the experiment, not only are the problems causing the fault found, the fault type and location are also determined. The feasibility of this method for detecting electrical faults of high-voltage equipment is confirmed, and the fault characteristics, location, and other information can be accurately judged, which provides support for the formulation of fault strategies in the later stage. [ABSTRACT FROM AUTHOR]

Alternating current (AC) copper losses in motors increase with carrier frequency of the pulse width modulation (PWM) and are further increased by leakage flux of the permanent magnet. Therefore, AC copper losses increase with motor speed. Conventional techniques for reducing AC copper losses tend to increase other losses. In this paper, AC copper loss was reduced by wrapping a magnetic tape made of a magnetic composite material around the winding. This method controlled the flux path through the winding. Magnetic composite materials are mixtures of magnetic powders and liquid resins whose magnetic properties can be manipulated by changing the combination and other factors. When Fe–Si–Al magnetic tape was wrapped around the winding, the AC copper loss was reduced by 40%. The loss was further reduced by optimizing the magnetic properties of the magnetic composite material. The AC copper loss was maximally reduced when the specific permeability was 100 and the saturation flux density was 1.6. Magnetic tapes composed of magnetic composite materials with high saturation flux density and specific permeability reduce the AC copper losses without increasing other losses in the motor.

The operating condition and structural state of the converter transformer are closely related to vibration. Abundant harmonics aggravate the vibration of windings and iron cores, resulting in frequent mechanical structural failures, which seriously affect the stable operation of the power system. Traditional research mainly focuses on the vibration of AC transformers without harmonics and there is no in-depth discussion of the vibration mechanism and the numerical calculation model of windings and iron cores under harmonics. In addition, the influence of harmonics, winding connection method and other factors on the vibration characteristics are not clear. Therefore, this paper analyzes the voltage and current harmonic components and contents, establishes a harmonic-vibration numerical model and compares the vibration time-frequency characteristics with or without harmonics and different valve side winding connections through vibration measurement experiments. Finally, a combined simulation analysis reveals the contribution of the windings and core to the tank. The results show that the tank vibration amplitude and dominant frequency will increase under harmonica and the valve side current will affect the dominant frequency. Among these results, when there are harmonics, the amplitude increases by three times, the vibration dominant frequency changes from 100 Hz to 400 Hz and the frequency spectrum widens to 2000 Hz. In particular, the contribution of the winding vibration under the harmonic current will exceed the iron core. The research results reveal the influence of converter transformer harmonics on vibration, which can provide a theoretical basis for numerical calculation of vibration and monitoring of operating conditions and guide the design of structural vibration reduction to reduce mechanical failures caused by vibration.

The dome reinforcement (DR) technology was studied to reduce the amount of carbon fiber of the type IV hydrogen storage vessel in this paper. Firstly, the influence of the angle and thickness of the dome reinforcement part on the stress distribution of the dome section is studied by finite element analysis. Secondly, the weight reduction of carbon fiber composite layer is studied based on the dome reinforcement model. The strain-based Hashin progressive damage model is used to predict the burst pressure and burst mode with user-defined material subroutine (UMAT) of ABAQUS. Finally, the dome reinforcement technology is further verified in comparison with non-dome reinforcement by burst tests. The results show that the progressive damage model can effectively represent matrix cracking and fiber fracture, and the predicted burst pressure and mode is consistent with the test results. The fiber stress near the equator of the dome section affects the burst mode, and the smaller the angle of dome reinforcement parts, the better the reinforcing effect, and the dome reinforcement technology can help to improve the fiber damage state at the dome, transfer the maximum stress to the cylinder section of the vessel, and ensure the burst mode to be a safe mode. Also, it can help to reduce the consumption of carbon fiber by up to 5.5% in composite material. [Display omitted] • The fiber stress near the equator of the dome section directly affects the burst mode. • The smaller the angle of dome reinforcement parts, the better the reinforcing effect. • The dome reinforcement parts can transfer the maximum stress to the cylinder section. • The dome reinforcement parts help to reduce carbon fiber consumption by up to 5.5%. [ABSTRACT FROM AUTHOR]

A new testing method (oscillating wave method) has been proposed as a solution to the problem of short maintenance time in the traction power supply system, which could complete tests of winding and insulation via one connection and improve the maintenance efficiency of the transformer. Through the method being proved highly sensitive to winding faults, the variation under different winding states, however, remains unclear. This article aims to analyze oscillating wave signatures in the occurrence of axial displacement (AD). First, the modeling method will be proposed that can simulate oscillating wave signatures in different winding states. Then, the time-domain feature and the new proposed frequency-domain feature are applied to analyze the fault extent and location of AD fault. The results show that this model accurately simulates oscillating wave signatures. Moreover, the time-domain feature [Euclidean distance (ED)] is closely related to fault extent. The combined use of the time-domain feature (ED) and the frequency-domain feature (W-Energy entropy in Z-Score) is effective in the identification of fault location. These features, therefore, can provide the reference for winding state evaluation. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Proposed a low-cost and superior design of linear actuator for agricultural robots. • Useful for long-track and multi-actuator operation. • Uses a stator permanent magnet less actuator model to reduce the cost. • Mathematical and finite element model of the design process are proposed. • Experiments are performed to validate the results. The electromagnetic performance improvement of a double saliency (DS) flux modulated (FM)- permanent magnet linear synchronous motors (PMLSM) for agricultural robots is proposed in this work by minimizing the effect of cross-coupling. To understand the effect of the cross-coupling on the electromagnetic performance, a dq axes model of the DS FM-PMLSM is developed and analyzed under different driving conditions. Based on the result obtained, winding modification schemes are proposed to minimize the thrust ripple and improve the zero torque control. The modified models are studied using finite element analysis (FEA) and the model with the best performance is selected for prototyping. The prototype is then tested and the results are validated against the electromagnetic performance obtained using the FEA. This research targeted the development of a low-cost linear actuator for a sapling grower gantry robot that can be used by farmers around the world. [ABSTRACT FROM AUTHOR]

Establishing an accurate stator system modal analysis model is of great significance for the vibration and noise analysis of the motor, scholars still have some controversy about how to set the material properties of the stator core and winding in modal analysis. First, the equivalent models of the stator core and winding was analyzed, the initial value of equivalent material parameters was determined. Second, the finite element models were used to analyze the influence of the equivalent material parameters on the natural frequency, a correction method of equivalent material parameters was proposed. Third, the modal of the stator core and the stator core with winding were tested by the moving force method. The finite element analysis results are consistent with the modal test results. Some influence laws of equivalent material parameters on natural frequency are obtained. The proposed correction method of equivalent material parameters helps to quickly determine the equivalent material properties of the stator core and windings. Setting the properties of the stator core and the winding material to the orthotropic materials can ensure the accuracy of the modal analysis.

Failure of the electric machine leads to emergencies, equipment downtime and, as a consequence, high economic costs to eliminate the results of machine failure. The failure of electrical machines at investigation, production and transportation of georesources in oil-extracting, mining, coal, chemical and other industries damages most of all the domestic economy. Reliability of these machines is determined by technological operations of impregnation and drying of windings. The most important qualitative characteristics of the windings are formed on these operations: electroinsulating, thermal, moisture resistant and mechanical. These properties depend on the degree of cavities filling of the winding with the impregnating composition. Low-quality impregnation of windings leads to the defects in the inter-coil insulation during storage and transportation of equipment to the place of operation. The development of quality control methods of windings impregnation is an actual problem. The aim of the work is to show the possibility of controlling the distribution of the impregnating composition on the winding by measuring the heat capacity of the windings before and after impregnation. Research methods: electrothermal and electromagnetic research methods, which are related to the measurement of thermal parameters of the winding and individual electrical quantities. Results. The paper considers the electrothermal method of quality control of windings impregnation. Physical bases of quality control of impregnation are proved. The paper introduces the derivation of the main criterions of quality assessment for technological operations and the scheme of the control device. The authors considered the principle of its operation and analyzed the errors for the offered method of control.

With the recent increase in the demand for convenient handheld home appliances, the quietness, power density, and weight of motors have been extensively studied. To this end, this article proposes a separated teeth motor (STM) with improved weight reduction and higher productivity than those of existing hair dryer motors. To reduce the weight of the stator, which possesses a high weight specificity in the motor, an STM model was designed with divided teeth to facilitate reduced iron consumption. Using this model, improvements in the production and performance of STM motors are proposed. For example, the workability of the motor is increased for the same torque; moreover, manufacture of compact and lightweight STMs is deemed possible. In addition, a reduction in torque ripple, cogging torque, and total harmonic distortion has been demonstrated via a finite-element method. [ABSTRACT FROM AUTHOR]