Construction Of Electrical Machines Research Articles

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.

Consideration of ferromagnetic anisotropy in electrical machines built of segmented silicon steel sheets

Electrical steel shows a distinct non-linear and anisotropic behaviour even for non-oriented steel. The flux guidance in electrical machines is realised by ferromagnetic steel sheets, and therefore it is necessary to consider the anisotropy in the simulation to have reliable and accurate results. Due to the fact that the reduction of silicon steel waste in the production process of electrical machines is crucial, and to enhance the material utilisation the segmentation is employed in the construction of electrical machines. The segmentation further allows to enhance the magnetic behaviour of the machine by considering the easy magnetisation axis in the design process. Nowadays, consideration of ferromagnetic anisotropy in the simulation of electrical machines is not accurate. To cope with these inaccuracies, in this contribution, a vectorial anisotropy model based on two-dimensional measurements is employed to the simulation of a segmented electrical machine, which is not state of the art in current machine computation. With the presented methodology, it is possible to simulate and design segmented electrical machines in an accurate fashion taking the ferromagnetic anisotropy into account.

A Comprehensive Review of Additive Manufacturing in Construction of Electrical Machines

Additive manufacturing (AM) has been undergoing dynamic development in recent years. The latest evolution of AM has been recognised as a key enabling technology in a wide range of applications, some of which include medical, aerospace and automotive industries. The use of AM opens new avenues for design solutions, otherwise challenging or impossible to realise when using more conventional techniques for manufacture. No- or low-material waste and high-flexibility are some of the attributes of modern AM. This expanded paper aims to provide an up to date overview of the existing examples of employing AM in construction of electrical machines. The paper reviews research and development work related to all integral components of an electrical machine assembly. These include active parts like coils/windings, electrical insulation, stator/rotor magnetic core packs, permanent magnets (PMs). The machine structural/mechanical and thermal management components are also discussed in the paper. Further to these, the authors make some comments/forecasts on how the AM could improve performance and manufacturability of the future electrical machines.

Analysis of Materials Used in the Construction of Electric Motors

Abstract The paper presents the evolution of electric motors from the point of view of the materials used. Magnetic materials and composite materials, which are used in the construction of electrical machines, are analysed. Composite materials based on magnetic materials have a large coercive field, a wider hysteresis cycle, they cannot be easily demagnetized and they absorb better the vibration energy - therefore the noise is reduced. In the design of electric machines, the aim is to obtain a higher magnetic permeability across the frequency spectrum and to reduce the losses in iron and copper. We analysed the radial electric motors with cylindrical magnets, electric motors in discoidal form with axial field and motors with magnets with transverse flux. Hard magnetic materials were presented and the advantage of their use was highlighted - they retain a significant residual magnetization which translates into a significant saturation magnetization. The synthesis of Fe nanoparticles is performed and the composite materials obtained from iron powders with organic or inorganic binders are analysed with the purpose of reducing iron losses in electric motors.

Characterizing the in situ Thermal Behavior of Selected Electrical Machine Insulation and Impregnation Materials

This paper presents results from an analysis of thermal behavior for alternative slot liner insulation and varnish impregnation materials used in the construction of electrical machines. These materials are typically characterized by the individual material properties altered to suit a particular application. However, the manufacturer provided material data are usually inadequate when comparing the complete insulation systems. This research is focused on the conductive heat transfer from the winding body into the machine periphery in context of the complete insulation system. An experimental approach using the stator-winding segment subassembly has been adopted here, for the representative in situ heat transfer measurements. The effects of impregnation “goodness,” in volume manufacture repeatability, and individual versus in situ material physical properties on the stator-winding thermal behavior are discussed in detail. The results suggest that the use of a particular slot liner insulation and varnish impregnation has a prominent impact on the winding heat transfer, as well as appropriate manufacture and assembly processes used. The experimental work has been supplemented with theoretical analysis to provide a more comprehensive insight into the winding heat transfer phenomena; in particular the winding-to-slot contact thermal resistance.

Generador Eólico Superconductor

This paper presents the properties of high temperature superconductor (HTS) materials in the construction of electrical machines. A disc type configuration synchronous generator with high specific power for future wind power applications is described. The generator is excited by means blocks of HTS ceramic materials. The mechanism to trap the magnetic flux in HTS blocks is explained. To decrease the weight of the generator on the top of the tower, the cryogenic system used consists of a liquid nitrogen storage container located on the ground to reduce weight on the tower. A flux plot per two poles of the machine calculated using the finite element method is presented and the flux density distribution in the air gap of the superconducting disc generator is also displayed. A high efficiency wind park with this type of generators is proposed.

Determination of 3D magnetic reluctivity tensor of soft magnetic composite material

Soft magnetic composite (SMC) materials are especially suitable for construction of electrical machines with complex structures and three-dimensional (3D) magnetic fluxes. In the design and optimization of such 3D flux machines, the 3D vector magnetic properties of magnetic materials should be properly determined, modeled, and applied for accurate calculation of the magnetic field distribution, parameters, and performance. This paper presents the measurement of 3D vector magnetic properties and determination of 3D reluctivity tensor of SMC. The reluctivity tensor is a key factor for accurate numerical analysis of magnetic field in a 3D flux SMC motor.

Macroscopic anisotropy characterization of SiFe using a rotational single sheet tester

Macroscopic magnetic anisotropy of two electrical steel samples of GO and NO SiFe materials are characterized thanks to a rotational single sheet tester. This nonstandard set up allows us to perform magnetic measurements under both a rotating excitation field and an alternating one applied along any direction of the sheet plane. The anisotropy of the magnetic losses and of the exciting field of each material quality is discussed. As expected, the GOSS texture of the GO SiFe is well pointed out with its very easy magnetization rolling direction. The hard magnetization axis at 55/spl deg/ emerges as the induction increases and replaces the transverse direction. The NO SiFe shows closely similar magnetic characteristics but remains anisotropic. The vectorial aspect of B(H) law is also highlighted. Such characteristics will be useful in many fields, e.g. material elaboration, magnetic law behaviour modelling and construction of electrical machines.