Manufacturing Of Electrical Machines Research Articles

Influence of welding-induced mechanical stress on the electromagnetic properties of magnetic lamination

PurposeThis paper aims to analyze the influence of welding-induced mechanical stress of a magnetic core material on the performance behavior of a permanent magnet excited synchronous machine (PMSM). Welding, interlocking, clinching and the use of adhesives are state-of-the-art packaging technologies used in the manufacturing of electrical machines. However, the packaging processes degrade the electromagnetic properties of the electric steel sheets, thereby decreasing the performance and achievable range of the electric vehicle.Design/methodology/approachIn this paper, an approach that maps the local changes in magnetic properties due to welding induced stress with the stress values is developed. The welding process induces internal stress inside the steel sheet due to the diffusion of thermal energy into the sheets. Other effects are the changes in the micro structures of the steel sheets (grain sizes). These induced mechanical stresses lead to significant deterioration of the electromagnetic properties. They also lead to an increase in iron loss attributed to steel lamination.FindingsA low speed (city), a high-speed (highway) and WLTC-c3 driving cycle will be used to analyze the effects of the induced stresses on the machine efficiency at the different operating conditions. A high-speed PMSM with a maximum speed of 26,000 min−1 and maximum torque of 130 Nm is designed for this study.Originality/valueThe value of this study is in the development of a local varying modeling approach that analyses the influence of weld-induced stress on the performance of electrical machines. Its originality is evident in the mapping methodology. This will enable an application dependent improvement possibilities due to the understanding of the impact of weld-induced stress on the electromagnetic properties of weld-packaged core.

A Review of Carbon Emissions from Electrical Machine Materials

As the world embarks on a global mission to tackle climate change, reducing carbon represents a key challenge given the escalating global warming. The U.K. is among many other nations that are determined to decarbonise all sectors and strive to achieve a net zero carbon target by 2050. While much attention has been paid to improving performance and reducing carbon emissions in electrical machines, the current research landscape focuses mainly on the thermal and electromagnetic facets. Surprisingly, carbon emissions from the production stage, especially those related to raw material consumption, remain a largely unexplored area. This paper wishes to shed light on a neglected dimension by providing a comprehensive review of carbon emissions in the manufacture of electrical machines, thus contributing significantly to the wider discourse on carbon emission reduction by comparing the carbon emission values associated with various materials commonly used for the main components of these machines. A further case study is included to assess and explore the impact of material alterations on a synchronous machine, from a carbon emission perspective. A reliable material guide will provide engineers at the design stage with the critical insight needed to make informed material selection decisions, highlighting the critical role of carbon emission values beyond conventional thermal and electromagnetic considerations, achieving sustainable and environmentally conscious electrical machine design.

Tensile and microstructural behavior of gas-tungsten-arc-welded electrolytic tough pitch copper joints

Electrolytic tough pitch (ETP) copper is extensively used in the manufacturing of electrical machines and automobiles. Compared with other pure coppers, ETP copper has lower weldability. Therefore, this study analyzes the weldability of ETP copper using the gas tungsten arc welding (GTAW) process. GTAW can be performed using constant-current (CC) and pulsed-current (PC) modes. Consequently, the properties of the joints fabricated using both modes are compared and analyzed in this study. The results show that the joint efficiencies of GTAW-CC and GTAW-PC joints are 81 and 89%, respectively. The optimal heat input and pulsating action in PC mode produce refined grains in the weld zone and heat-affected zone, resulting in a higher joint efficiency.

Blue laser welding of laminated electrical steels: Dynamic process, weld bead characteristics, mechanical and magnetic properties

Laminated electrical steels are the key material structure of the stator and rotator of a motor, where high-quality welding is crucial for improving the performance of the electric machine. However, it is challenging to achieve a desired balance among the magnetic properties, mechanical properties, and welding efficiency for the laminated electrical steels at present. This work first adopted a 450 nm flat-top blue laser with a maximum power of 2000 W, which has a higher primary absorption rate to Fe compared to that of the conventionally used 980-1080 nm infrared laser, to join the laminated electrical steels. The dynamic process, weld bead characteristics, mechanical properties, and magnetic properties of the blue laser welding of laminated electric steels were investigated. The results show that a flat-top and large-spot blue laser can make the molten pool have a self-stabilizing ability to keep the continuity when encountering the gap and unsmooth surface. Moreover, a further improved self-stabilizing ability is observed for a small welding speed. The largest depth and width of the blue laser weld bead in this work are 2.30 and 0.57 mm, respectively, with a shear strength of up to 1700 N, which are achieved at the laser power of 1500 W and welding speed of 10 mm/s. In addition, the work also validated that the blue laser could significantly reduce the splashing in welding of electrical steel laminations and improve the welding efficiency, which provides a promising solution for high-performance electrical machine manufacturing.

Additive Manufacturing of Electrical Machines—Towards the Industrial Use of a Novel Technology

For several decades, the design and manufacture of electrical machines has been considered a technically mature area and, as a result, research and development in the area has been extremely limited, even though this is a crucial technology in the application of electrical energy. Electrical machines are used in over 80% of the world’s energy conversion processes—first to create electrical energy, which can be easily transmitted, and second to convert that energy into mechanical form for applications ranging from dishwashers to transportation, and from medical devices to those used for industrial processes. Today, two technologies are changing this. The first is the development of power electronic drives and the second is the introduction of additive manufacturing technology. The latter technology has opened up new areas for innovation and research, and many conventional processes are likely to become obsolete. Considering the overall consumption of electricity by electrical machines, the design freedom granted by the novel production technology gives the opportunity for even more efficient, object-oriented machines to be built, with a lower environmental impact and less raw material consumption. If this technology can be developed to maturity, it would have a significant positive impact on the desired green transition that is being pursued all over the world.

An investigation on applications of additive manufacturing of electrical machines

Additive Manufacturing is a computerized method in industrial production that enables the creation of lighter, stronger components and systems. It has actually been around us for several decades. In the right applications, additive manufacturing comes up with a lot of improved performance, complex geometries and simplified fabrication. As a result, opportunities will be present in large quantities for those who actively embrace additive manufacturing. This paper reviews the up to date overview of additive manufacturing in the construction of electrical machines. This review investigates the research and developments in the manufacturing of different components of electrical machines and possibilities.

A prototype of 3D-printed permanent magnet generator for low power applications

Recently, there has been a growing interest in the field of using 3D-printing technology for electrical machine manufacturing. However, almost research works have been done majorly on the 3D-printing technology of individual working parts for various electrical machines. This research presents a study of design, fabrication and testing of the protopype of permanent magnet generator using 3D-printing technology. The major parts of proposed generator are fabricated though 3D-printed materials. The stator winding of designed generator consists of 12 slots. The stator coil is designed to have 250 turns per slot and 12 pieces of neodymium magnets are used in to generate magnetic field in the rotor core. The prototype generator is tested under different condition; no-load and loaded-test. The experimental have been shown that in the no-load condition, this generator is able to generate output voltage of 3.3-64.5 V, when rotated at speed of 100-2,500 rpm. In the loaded-test, the output voltage and output current are also generated. Furthermore, it can be seen that a proposed generator can generate the output power of 4,245.28 mW, when rotated at speed of 2,500 rpm.

Adaline-Based Control Schemes for Non-Sinusoidal Multiphase Drives–Part I: Torque Optimization for Healthy Mode

More degrees of freedom not only enable multiphase drives to be fault-tolerant but also allow non-sinusoidal electromotive forces (NS-EMFs) in high-quality vector control. NS-EMFs lead to lower costs of design and manufacturing of electrical machines. However, the presence of multi-harmonics in NS-EMFs possibly generates pulsating torque in both healthy and faulty conditions of multiphase drives. To facilitate the use of NS-EMFs, this two-part study proposes control schemes to adaptively improve torque quality of multiphase drives in dealing with multi-harmonics of NS-EMFs. The proposed schemes are based on a simple but effective type of artificial intelligence, Adaptive Linear Neuron (Adaline). The knowledge of multiphase drives including the harmonic ranks of NS-EMFs and the rotor position is exploited to design the online-trained optimal Adalines. The first part of this study is to propose a control scheme using an Adaline for healthy mode with high-quality torque regardless of numerous harmonics in NS-EMFs. The second part of this study introduces a control scheme using another Adaline for open-circuit faults. The proposed schemes are numerically and experimentally validated on a seven-phase permanent magnet synchronous machine (PMSM) possessing a high total harmonic distortion (THD = 38%) of NS-EMFs.

Challenges in Winding Design and Thermal Calculations: Physical Model of Permanent Magnet Synchronous Machine

Interest in multilayer windings is increasing with the application of the hairpin winding technology to the manufacturing of electrical machines. Therefore, the four-layer fractional slot concentrated winding is used for the initial design of the machine in this paper. The proposed physical model of the machine uses winding with a relatively high number of turns which is inappropriate to hairpin winding. Therefore the round-wire winding is created and the three-layer winding is derived and analyzed including the effect on the slot leakage inductance. The thermal analysis is then applied to the physical model of the machine to evaluate the slot-related thermal properties of the slot and the whole machine. The measurement is compared with the finite element analysis (FEA) and the equivalent slot thermal conductivity and heat transfer coefficients of the stator and rotor are obtained.

FMEA Application in the Design and Manufacture of Modern and Advanced Electrical Machines

In this paper, an original design failure mode and effects analysis methodology that can be applied to all modern and advanced electrical machines has been proposed. The developed methodology application is possible in the real electrical machines manufacture, which is confirmed by “Tekhnodinamika” holding representatives. On the example of the high-torque permanent magnets synchronous motor, the stages of the electrical machine hierarchical decomposition, the definition of the electrical machine and its components functions, the theory of failures and failure modes have been considered. The prospects and the opportunities that failure mode and effects analysis open in the design and in the production of modern and advanced electrical machines have been described. Proposed failure mode and effects analysis methodology application in electrical machines engineering will allow avoiding serious failures in commercially available electrical machines, as well as collecting into one system the rules that should be followed by electrical machines designers and manufacturers. The regulated failure mode and effects analysis methodology usage in the electrical machines design and manufacture should significantly improve the quality of manufactured products, increase its competitiveness and consumer qualities, and also reduce production costs.

In-process monitoring in electrical machine manufacturing: A review of state of the art and future directions

Manual operations feature prominently in the manufacture of many electrical machines. Even though high-volume electrical machine manufacture is dominated by automation, several manufacturing operations continue to involve manual intervention because of the complexity of such operations makes them heavily reliant on high dexterity manual skills and experience. However, quality can be variable due to human involvement. Currently, in order to maintain a high precision of control and required tolerances of the final machine, inspection is performed at various steps during manufacturing and assembly. Detecting a defect at these end-of-line tests can result in significant wasted time and costs due to rework or scrappage. The solution to this problem lies in in-process monitoring particularly for error prone manual operations. This paper presents a literature review of the state-of-the-art available techniques and limitations in process monitoring within the context of electrical machine manufacturing. To quantify the degree of manual activities in process monitoring within electrical machine manufacture, a structured survey of UK based companies was conducted, identifying specific error prone manual processes to target, and gaps in inspection. The survey identified that a significant proportion of activities in electrical machine manufacture are manual, or semi-automated with manual interventions. However, literature review revealed only a limited research in in-process monitoring of manual operations in this area. Finally, two case studies are presented where case study 1 presents a framework for digitisation of a variety of manual manufacturing tasks, and case study 2 demonstrates real-time capture, modelling and analysis of deformable linear objects in electrical machine manufacturing.

AC Magnetic Loss Reduction of SLM Processed Fe-Si for Additive Manufacturing of Electrical Machines

Additively manufactured soft magnetic Fe-3.7%w.t.Si toroidal samples with solid and novel partitioned cross-sectional geometries are characterized through magnetic measurements. This study focuses on the effect of air gaps and annealing temperature on AC core losses at the 50 Hz frequency. In addition, DC electromagnetic material properties are presented, showing comparable results to conventional and other 3D-printed, high-grade, soft magnetic materials. The magnetization of 1.5 T was achieved at 1800 A/m, exhibiting a maximum relative permeability of 28,900 and hysteresis losses of 0.61 (1 T) and 1.7 (1.5 T) W/kg. A clear trend of total core loss reduction at 50 Hz was observed in relation to the segregation of the specimen cross-sectional topology. The lowest 50 Hz total core losses were measured for the toroidal specimen with four internal air gaps annealed at 1200 °C, exhibiting a total core loss of 1.2 (1 T) and 5.5 (1.5 T) W/kg. This is equal to an 860% total core loss reduction at 1 T and a 510% loss reduction at 1.5 T magnetization compared to solid bulk-printed material. Based on the findings, the advantages and disadvantages of printed air-gapped material internal structures are discussed in detail.

Improving Global Ferromagnetic Characteristics of Laminations by Heterogeneous Deformation

During electrical machine manufacturing, the process may induce plastic mechanical strains, especially in the magnetic core. However, magnetic properties are highly sensitive to the material mechanical state. Thus, the performances of electrical machines, which also rely on the magnetic material properties, are often deteriorated. This article proposes an approach to reduce the impact of the forming process on the magnetic core performances by creating high localized heterogeneous deformations instead of having a low homogeneous deformation distributed on the whole structure. A NO (non-oriented) FeSi (1.3%) electrical steel (M330-35A) is characterized after uniaxial tensile test. Samples are deformed either in heterogeneous or in homogeneous ways while keeping the same global deformation. Experimental measurements show that, for the same displacement value, the heterogeneous configuration, with localized strain, deteriorates less the global magnetic properties than the homogeneous configuration. These results are supported by a magneto-mechanical modeling approach that predicts accurately the physical behavior of the test samples.

Effects of Manufacturing Processes on Core Losses of Electrical Machines

Manufacturing processes such as cutting, welding and shrink fitting are known to degrade the magnetic properties of the electrical sheet during the manufacturing of electrical machines. These effects are often neglected at the design stage and lead to large errors in the simulated and measured core losses of the electrical machine. This article studies the comparative impact of different manufacturing processes on the stator core losses of a typical industrial motor. Both simulations and measurements indicate a significant impact of manufacturing processes on the stator core losses. A dummy blocked rotor test setup is used to measure the stator core losses. As a result of different manufacturing processes, the stator core losses increased by 23% in the studied machine at the rated condition. The effect on the stator core losses was higher at lower flux levels. Finally, it was shown that the inclusion of the effect of manufacturing processes significantly improved the simulation accuracy of the core losses. A quantification and segregation of the effect of cutting, welding and shrink fitting is also presented for the studied machine.

Enhanced Flexible Algorithm for the Optimization of Slot Filling Factors in Electrical Machines

The continuous development in the field of industrial automation and electric mobility has led to the need for more efficient electrical machines with a high power density. The improvement of electrical machines’ slot filling factors is one of the measures to satisfy these requirements. In recent years, this topic has aroused greater interest in the industrial sector, since the evolution of the winding technological manufacturing processes allows an economically sustainable realization of ordered winding arrangements, rather than random ones. Moreover, the manufacture of electrical machines’ windings must be preceded by an accurate design phase in which it is possible to evaluate the maximum slot filling factor obtainable for a given wire shape and for its dimensions. For this purpose, this paper presents an algorithmic approach for the evaluation of maximum slot filling factors in electrical machines under an ideal geometric premise. In particular, this algorithm has a greater degree of flexibility with respect to the algorithm approaches found in the literature, since the study has been extended to round, rectangular and hexagonal wire sections. Furthermore, the slot filling factor calculation was carried out both for standard and non-standard slots. The algorithmic approach proposed can be considered as an additional useful tool for the fast design of electrical machine windings.

Effect of Laser Cutting on Core Losses in Electrical Machines—Measurements and Modeling

Cutting of the electrical steel sheets to appropriate shape and size is performed during the manufacturing of electrical machines that leads to the magnetic material deterioration near the cutting edge. Epstein frame measurements of electrical steel samples of different widths cut by laser cutting are carried out in the range of 20–400 Hz frequency of sinusoidal excitations. Two stators one with laser cut and another one with electric discharge wire cutting are manufactured and the effect of cutting on core losses is analyzed. The effect of cutting on the magnetic permeability and core losses are modeled with analytical equations. Furthermore, the model is implemented in the finite-element (FE) simulation of the Epstein frame test setup. The presented loss model is found to reproduce the measurement results reasonably. The loss model is then applied to the simulation of a cage induction machine with time-stepping FE analysis (FEA). A significant increase in core losses was observed both in simulations and measurements due to the effect of laser cutting. The presented cutting model closely follows the measured core losses.

Preliminary Analysis of Soft Magnetic Material Properties for Additive Manufacturing of Electrical Machines

Additive manufacturing (AM) technology has the potential to revolutionize multiple fields of industry Defect formation is a common problem in all AM processes. For the applicability of this technology for manufacturing electrical machines, specific mechanical and electromagnetic properties of printed material are necessary. In this paper we present a literature review on the effects of production parameters on the printed material properties, alongside experimental results of printed electrical steel sample properties with default processing parameters.

A novel approach for developing a flexible automation system for rewinding an induction motor stator using robotic arm

Abstract Electric motor rewinding is a traditional restorative and regenerative process, which is lagging in adopting new and current market trends. Stator rewinding is a crucial task in electric machine manufacturing and is the most challenging operation. This has raised the need to automate the system. In this light, this paper aims to develop a concept for developing a flexible automation system for rewinding an induction motor stator using a robot arm. To achieve this, a bottom-up approach and model predictive control (MPC) has been utilized in the design due to manufacturers’ specification disparities. The results reveal that the system can be trained successfully, to perform the remanufacturing process 6 times faster than the manual process. The system also allows for data mining. Successful application of this approach will demonstrate the importance of using flexible automated systems for induction motor stator rewinding and reduce time and winding steps.

Magnetic Materials Used in the Magnetic Core Manufacture of Electrical Machines and Transformers

Two types of silicon iron steels, M400-65A non-oriented and MOH grain-oriented alloys were characterized using an industrial Brockhaus Single Strip Tester at two peak magnetic polarizations of 500 mT and 1000 mT in the frequency range from 10 Hz to 100 Hz. The samples were cut parallel to the rolling direction trough different cutting technologies, which are the classical mechanical-, then the non-conventional laser-, water-jet-and traveling wire electro-erosion methods. The loss separation concept was applied and the total energy losses, determined experimentally, for each sample were decomposed into hysteresis, classical (Foucault) and excess (anomalous) energy losses. A detailed analysis of each type of losses as a function of the frequency was made and the influence of the cutting technology was analyzed.

Mixed-Order Finite-Element Modeling of Magnetic Material Degradation Due to Cutting

As a part of manufacturing of electrical machines, electrical sheets are cut to the desired shape by various cutting techniques, such as punching and laser cutting. This cutting process degrades the magnetic material near the cut edge, which should be included in the finite-element modeling of electrical machines. However, due to the nature of the cutting effects, the existing finite-element modeling of the cutting effect results in computationally heavy simulations. This paper investigates the application of mixed-order elements to model the cutting effect. The second-order nodal triangular elements are used near the cut edge, whereas transition/first-order elements are applied in the remaining solution domain. Furthermore, the accuracy of the presented method is analyzed with the traditional method. According to the simulations, the mixed-order elements returned accurate results significantly faster than the traditional finite-element-based approaches. Furthermore, the effect of the cutting on the machine performance is also studied by comparing its results briefly.