This study aims to explore an economically feasible enameled wire technology based on sol-gel, offering enhanced performance compared to traditional enameled wire. The evaluation involves assessing insulation configurations for copper wires designed for high-temperature applications, with a proposed configuration combining sol-gel solution on enamel and polyphenylene sulfide (PPS) extrusion resins. Electrical performance is compared across these insulation configurations, building upon their demonstrated higher thermal performance in prior research. Experimental data, including partial discharge (PD) parameters, dielectric strength, and electrical aging endurance, are collected from twisted pair samples for each insulation type. Promising results emerge from PD studies, favoring hybrid technology (enameled-extruded wires) over the classical approach polyesterimide (PEI) + polyamide (PAI) enameled wires. Measurements reveal a higher intensity of PDs for classical enameled wires under 3 kV-50 Hz. Moreover, lifespan models under voltage stress indicate that enameled-extruded wires with PPS extruded resin have advantages, withstanding 1525 min compared to 530 min for classical wires under 3 kV-50 Hz. A correlation between lifespan under voltage stress and PD intensity is observed. Furthermore, microfillers on PPS show lower results compared to nonfilled enameled -extruded wire configurations.

The principal aim of this work is to compare some electrical properties characterized experimentally on samples of enamelled wires developed from two kinds of coating insulation processes. It consists of an evaluation of the dielectric strength, Partial Discharge Inception Voltage (PDIV), and voltage endurance accordingly to IEC standards. Enamelled-extruded wires are evaluated, its insulation comprises an enamel primer on PAI, a second enamel coat of PAI-silica composite produced through the sol-gel process, and a topcoat on PPS resin. The same properties had been characterized on conventional enamelled wire samples (PEI and PAI) for comparison. The breakdown voltage measurements are carried out under 3kV (50Hz), and the lifetime data of twisted pairs samples are collected. The analysis of those results employs the Weibull distribution. The PDIV of these wires is measured, the results obtained show some advantages of the enamelled-extruded wires being 781 V (conventional wire PDIV = 668 V). The lifetime under 3kV (50Hz) has demonstrated an advantage for this type of wire, with α=1616 minutes compared to α=529 minutes for conventional wires. The dielectric strength is very similar between both kind of wires, with α=104.5 V/µm for the enamelled-extruded and α= 109.4 V/µm for the conventional wire. This study shows the increased electrical properties of enamelled-extruded wires compared to conventional ones. This advantage is significant regarding the electrical endurance under high voltage. This kind of insulation has the potential properties to be employed in winding applications and is also an eco-friendly solution compared to the conventional wires.

Insulated wires are components of devices employed in different applications, such as in the automobile and aerospace industries, and renewable generation equipment (e. g. wind power). The interest in improving magnet wires is relevant to the industry sector, especially for electrical machine winding [1] , [2] . The performance of magnetic wires is fundamentally dependent on the quality of their Electrical Insulation System (EIS). Further knowledge of insulation properties may point to ways of improving this. Several properties as mechanical, thermal, chemical, and electrical must be considered for the manufacturing of magnet wires. Some standards establish protocols for the evaluation of those properties, such as IEC 60317-0-1 [3] .

The conventional enameling process used in the fabrication of magnet wires requires harmful processes and products. The target of the industry in the actual context of electrification is to increase the electrical machines’ efficiency. Indeed, the electrical insulation systems (EIS) of an electrical machine undergo various environmental constraints that can shorten their lifespans. Consequently, aspects of the insulation need to be improved, such as its thermal resistance. One of the challenges is to implement sustainable technology without losing performance. This work consists of the thermal performance evaluation of new magnet wires insulated by three types of composites of silica-based solution from the Sol–gel process and amorphous polyamide-imide (PAI). These composite coats are overcoated by an extruded thermoplastic resin with and without fillers. Different types of insulation are tested and compared to determine the better configuration. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) analysis, scanning electron microscopy (SEM) analysis, curing characteristics by tangent delta curve, and thermal-aging tests at three temperatures were carried out on the different EIS systems. Dielectric measurements were made between thermal-aging cycles. Their basic mechanical, electrical, and thermal characteristics are promising: the cut-through temperature is situated above 430 °C, their breakdown voltage values are between 5 kV and 9 kV (grade 3), and a good adhesion (overcoming more than 140 turns on a peel test). The thermal-aging results have been consistent with the TGA analysis results. The thermal index following the IEC standards was estimated for the selected EIS, which would have the main basic characteristics of a magnet wire of 200 class; moreover, it would be a greener enameled wire compared to the conventional one.

There are systems dedicated to measuring the eccentricity of enameled wires based on optical and electromagnetic phenomena. However, these methods are limited by the nature of the insulation and the conductor. The proposed solution consists of checking the wire eccentricity by an electrical measurement. Since it is a conductor on which an insulator is placed, the idea consists of forming a capacitor and measuring its capacitance in order to deduce the insulation thickness.

This research activity aims to evaluate electrical insulation system (EIS) intended for electrical machine winding wires. The evaluation is based on mechanical, thermal, and electrical properties tests following international standards for enameled wires. Dielectric parameters such as dissipation factor, partial discharge inception voltage (PDIV), parallel capacitance, and parallel resistance behavior of different insulator configurations on twisted-pair samples are observed during thermal aging tests. Those configurations are formed of different combinations of dielectric layers based on conventional polymers (polyester-imide (PEI), polyamide-imide (PAI), polyimide (PI)) used as coating wires. A study using two mineral varnishes (silica-based) obtained by the sol-gel process integrated on these classical enamels an outer layer of extrusion of thermoplastic polymer with and without mineral fillers. Given the high consummation of energy and the use of unsustainable materials involving the production of wires, the principal interest of this work is to exploit new configurations of coating wire produced, with less environmental impact than conventional ones. This work investigates the impact of filled resins on the performance of insulating samples and the influence of the use of sol-gel solutions (mineral varnishes) on the insulated wire to increase the thermal class.

The principal purpose of this work is to investigate the performance of new technologies of electrical insulation (Solgel material top coated with an extrusion layer) intended for winding machines wires. New configurations of coating wire produced by an eco-friendly process, with less environmental impact than conventional ones, are tested and compared. The working method is based on measurements of samples that are produced in accordance with international standards to characterize the electrical and thermal properties of the insulated wires. The performance analysis of insulations is composed of a sequence of dielectric tests and thermal aging tests. This latter test is realized after validation of the basic electrical and mechanical tests. During thermal aging, the parallel capacitance, tangent delta, and Partial Discharge Inception Voltage (PDIV) are measured to investigate the evolution of those dielectric parameters and to compare dielectric behaviour between different configurations of insulating materials. The results of the tests show that an extrusion resin with fillers had a longer lifetime compared with non-filled resins. The concentration of sol-gel influenced the lifetime of insulated wire. This study shows some indicators of thermal improvement, but the percentage of sol-gel used is yet very low and therefore, far from the main objective of using fully sustainable products. The sol-gel formulation tested in higher concentrations had a lower performance of basic mechanical properties required for winding wires. However, the extrusion process for magnet wire insulation is possible and gives good results with pure stable thermoplastic polymer and mineral fillers on extrusion resins.

Electrical machines are commonly used in industries and transport and are manufactured with enameled wire coils with polymer insulation. In extreme conditions, as in aeronautics and aerospace, where temperatures exceed 280 °C, the organic insulation deteriorates and it is necessary to find another way to insulate winding wires, in order to ensure a longer life duration of the insulation system and a better operating reliability of electric motors in these environments. Ceramics are more resistant to high temperatures than polymers and the proposed study focuses on the temperature dependence of the dielectric properties of anodized aluminum strips for use in high-temperature electrical machine windings. Different dielectric parameters are measured during thermal constraint. The purpose is to determine the temperature index of the anodized strip and propose a thermal stress life model.

The project objective is to evaluate the reliability of motor winding technologies able to work at higher temperatures than those currently used in the field of aeronautics or other applications. To achieve this goal, it is necessary to rely on existing European technologies, which offer opportunities for rapid implementations on conventional machines, while opening new opportunities towards higher

An active vibration control system has been developed based upon analogue feedback and optical vibration sensing. ZnO thin films have been deposited using r.f. magnetron sputtering onto silicon substrates and cantilevers fabricated using photolithography. These cantilevers provide a means of actuation and micro-positioning. The system operates such that unwanted vibrations in the cantilever are removed and yet it remains possible to deflect the cantilever statically or dynamically as required. Results are presented for such a system.

This paper aims to present and analyze the materials adapted to design a machine that can work with a high current density without any specific cooling system. In other words, the machine is equipped with material that supports high internal temperature, about 500°C. Candidate materials are selected and the authors indicate that inorganic insulation should be preferred for conductors and slot insulations. Tests are carried out on material selection through measurement of the turn-to-turn voltage, insulation resistances, and the parallel capacitances.

The paper proposes a comparative approach of two wire technologies for making compact coils able to operate in high temperature (HT degrees) machines. The first technology is based on ceramic-coated round wire associated with a HT degrees cement. The second one uses anodized aluminum strips. The advantages and drawbacks of the two technologies are compared, considering the machine global performances at high temperatures.

The increase of the operating temperature of electrical machines is a major challenge in the context of the large-scale use of electricity in many industrial or individual applications such as mobility. Indeed, working at higher temperatures makes it possible to place electrical actuators in critical areas – such as aircraft engines, for example – and/or to significantly improve the power-to-weight ratio of the machine. For several applications (deep pumping, ventilation, etc.), the use of the induction machine is still preferred due to cost, simplicity and robustness essentially. The objective of this study is to estimate the possibilities of making a high-temperature squirrel cage induction machine. A significant increase in the operating temperature of a machine would indirectly allow us to envisage an increase in the current density in the active conductors and thus a significant improvement in the power-to-weight ratio. However, this is at the sacrifice of efficiency. The aim of this study is to evaluate this decrease in efficiency correlated with the increase in the temperature to find the best compromise according to the relevant applications. An analytic sizing model has been proposed for the prediction of losses, which will be coupled with a thermal model to predict the temperature in different parts of the machine. This study presents essential information on the influence of temperature on the parameters important for the performance of an induction machine.

The requirement for electrical machines operating at extremely high temperatures has prompted researchers to focus on new materials. The use of nickel-coated copper (Cu/Ni) wires can be a promising alternative to copper wires because of their resistance to oxidation at high temperatures. In this article, the characterization of Cu/Ni wires’ electrical resistance in the frequency domain as well as the measurement of pure nickel’s B(H) curve have been specified. The effect of nickel coated on a copper wire is remarkable in terms of electrical resistance at high frequencies because of the skin effect and eddy currents. An original model has been proposed for the prediction of the electrical resistance. The originality is to consider the bimetallic conductor as a transformer in order to generate its model. Since the analytical calculation is not possible because of the nonlinearity of the nickel’s magnetic properties, a new numerical computational method for the determination of the impedances was proposed. The modeling results are correlated with the experimental tests made on 3 Cu/Ni wires: 0.3 mm diameter with 27% of nickel in volume and 0.5 mm diameter with 8 and 18 $\mu \text{m}$ nickel thickness. This article, thus, provides essential information about the important parameters for the performance of electrical machines.

This paper proposes a model-based decision taking solution for electrical machines winding insulation robustness study. The solution is based on the Belief Function (BF) theory. It is processed in two main steps: a first one aims to learn Weibull model parameters from some labeled aging Partial Discharge Inception Voltage (PDIV) data. Then a second classification step separates some unlabeled PDIV data according to the learnt Weibull models. The classification results can give information on the robustness and the reliability of the Electrical Insulation System (EIS) under a thermal constraint.

In the past few years there has been a growing trend in the use of ceramic coated high temperature resistant wires for applications up to 500 °C. The main drawback in developing new materials has been the relatively poor dielectric characteristics at high temperature. One solution is to strengthen the ceramic layer by covering it with boron oxide and this additional layer improves the dielectric characteristics of the ceramic wire. Partial discharge inception voltage threshold is greatly increased compared to non-impregnated wires and this has been observed over a large temperature range.

Collection Authors Metrics License Sponsors

This paper presents the preliminary sizing of a High Temperature (HT°) induction motor based on a copper cage rotor and a distributed winding built with an inorganic Electric Insulation System (EIS) able to withstand 500°C. The specific part of the design derives of the poor mechanical and electrical characteristics of the inorganic HT° insulation materials. HT° wires are protected by a cement and form rigid coils. The laminated magnetic core has a specific design for suiting with the rigid coils. An Electrical and thermal models are validated.

This paper proposes a model-based decision taking solution for electrical machines winding insulation robustness study. The solution is based on the Belief Function (BF) theory. It is processed in two main steps: a first one aims to learn Weibull model parameters from some labeled aging Partial Discharge Inception Voltage (PDIV) data. Then a second classification step separates some unlabeled PDIV data according to the learnt Weibull models. The classification results can give information on the robustness and the reliability of the Electrical Insulation System (EIS) under a thermal constraint.

The most common method for the electrical steel sheet characterization uses the Epstein frame. However, in the case of high-temperature characterization, the standard Epstein frame is not adapted to high temperature measurements. This paper deals with the design of an Epstein frame adapted for high temperature measurements, up to 600 degrees C. In a first step, the results at ambient temperature obtained between the normalized Epstein frame and the high-temperature device for different frequencies are compared in order to validate the new frame. The second step is dedicated to the characterization of soft ferromagnetic materials in high temperature, up to 600 degrees C and for different frequencies. Moreover, the effect of sheet thickness on their behavior has been studied at high temperatures. The obtained measurement results confirm the strong influence of both temperature and thickness on power losses.