Application-oriented Method for Determining the Adhesion between Insulated Flat Copper Wire and Impregnation Resin

In the field of hairpin stator technology, increasing demands are currently being made on the semi-finished product of insulated flat copper wire. In particular, the focus is on the electrical requirements against the background of increasing voltage levels to 800 V and more. The test procedures described in the standards IEC 60317 & 60851 for verifying the properties of insulated flat copper wires only partially map the requirements from the point of automotive industry. An example for insufficiently considered properties lays in the correlation between wire and insulation resin. In addition to electrical and thermal benefits, impregnation helps to mechanically stabilize the winding and protect it from ambient factors. Adhesion between the winding and the impregnating resin is a key parameter here, but is not considered in material pre-selection today. The adhesion of the impregnation resin to the insulated wire is essential to ensure the lifetime of electric motors. This paper describes a method for determining the adhesion of the impregnating resin to the insulation of the wire. It could be shown that there is a correlation between the material of the wire insulation and the impregnating resin in terms of adhesion. Further on the described method can be used for an application-oriented specification of insulated copper flat wires to ensure a consistent composition of the insulation material

A Spectroscopic Study of Mechanochemically Activated Kaolinite with the Aid of Chemometrics

The study of kaolinite surfaces is of industrial importance. In this work we report the application of chemometrics to the study of modified kaolinite surfaces. DRIFT spectra of mechanochemically activated kaolinites (Kiralhegy, Zettlitz, Szegi and Birdwood) were analysed using, Principal Component Analysis (PCA), and multi-criteria decision making (MCDM) methods, PROMETHEE and GAIA. The clear discrimination of the Kiralhegy spectral objects on the two PC scores plots (400-800 and 800-2030 cm-1) indicated the dominance of quartz. Importantly, no ordering of any spectral objects appeared to be related to grinding time in the PC plots of these spectral regions. Thus, neither the kaolinite nor the quartz, are systematically responsive to grinding time according to the spectral criteria investigated. The third spectral region (2600-3800 cm-1 – OH vibrations), showed apparent systematic ordering of the Kiralhegy and, to a lesser extent, Zettlitz spectral objects with grinding time. This was attributed to the effect of the natural quartz on the delamination of kaolinite and the accompanying phenomena (i.e. formation of kaolinite spheres and water). With the MCDM methods, it was shown that useful information on the basis of chemical composition, physical properties and grinding time can be obtained. For example, the effects of the minor chemical components (e.g. MgO, K2O etc) indicated that the Birdwood kaolinite is arguably the most pure one analysed. In another MCDM experiment, some support was obtained for the apparent trend with grinding time noted in the PC plot of the OH spectral region

Challenges of the continuous hairpin technology for production techniques

In the electrification of the automotive drive train, an unprecedented change is currently influencing the production technology of stators. Previously established round wire winding technologies are being replaced by windings made of thick rectangular conductors specially tailored to the requirements of mobile electric traction. A cascading technology development from the I-pin to the currently established U-hairpin technology can be observed. Continuous hairpin technology (CHP), also known as wave winding or S-wind, is increasingly under investigation of the industrial sector. In this winding technology, solid, usually, rectangular conductors are continuously inserted into a lamination stack. Decisive product and production advantages are found in the leaner production process chain, the reduced winding head heights and contact points. However, numerous design and process limitations are also associated with this winding technology. This paper describes the process chain of continuous hairpin technology, identifies process limitations and points out challenges and approaches for future production technology

Technical and Economic Analysis to Select Suitable Design Parameters of an E-Machine for Electric Commercial Vehicles

In the European Union (EU), road transport contributes a major proportion of the total greenhouse gas (GHG) emissions, of which a significant amount is caused by heavy-duty commercial vehicles (CV). The increasing number of emission regulations and penalties by the EU have forced commercial vehicle manufacturers to investigate powertrain technologies other than conventional internal combustion engines (ICE). Since vehicle economics plays an important role in purchase decisions and the powertrain of a battery electric vehicle (BEV) contributes to about 8–20% of the total vehicle cost and the electric machine (EM) alone contributes to 33–43% of the drivetrain cost, it is necessary to analyze suitable EM topologies for the powertrain. In this paper, the authors aim to analyze the technical and cost aspects of an EM for electric commercial vehicles (ECV). Based on prior research and literature on this subject, an appropriate methodology for selecting suitable geometrical parameters of an e-machine for the use case of a heavy-duty vehicle is developed using MATLAB and Simulink tools. Then, for the economic analysis of the e-machine, reference ones are used, and their design parameters and cost structures are utilized to develop a cost function. Different use cases are evaluated according to the vehicle’s application. The results for a use case are compared by varying the design parameters to find the most cost-effective EM. Later, an analysis is performed on other decisive factors for EM selection. This highlights the importance of collaborative consideration of technological as well as the economic aspects of EMs for different use cases in ECVs. The method developed in this work contributes to understand the economic aspect of EMs as well as considering their performance factors. State-of-the-art methods and research are used to develop a novel methodology that helps with the selection of the initial geometry of the electric motor during the design process, which can serve to aid future designers and converters of electric heavy-duty vehicles