Innovative SMC Insulation Technique Applied to Axial Flux Machine Prototypes

The paper describes in detail the realization of an axial flux machine prototype adopting an innovative Soft Magnetic Composite (SMC) material. The novel technique here presented regards a Layer-by-Layer deposition adopted to insulate pure iron powder grains previously selected. The obtained material is then used to prepare the machine's stator parts. The activity steps are detailed: from the powder preparation to the molding phase, the consequent milling for the final shape, and the consequent magnetic, energetic and mechanical characterization. The prototype design and assembly imply the realization of the stator with the adopted innovative material, and the Authors also realized the preparation of the rotor equipped with bonded magnets. The preliminary experimental results are presented at the end, and considering the machine to be the first trial with the presented material, the efficiency of 77% should be viewed as a promising result for the future development of the activity

Rapid Characterization Method for SMC Materials for a Preliminary Selection

In electrical machines, laminated steels are commonly adopted as soft magnetic materials, while for permanent magnets, sintered ferrites and NdFeB are the most common solutions. On the other hand, the growing demand for volume reduction with the increment of efficiency leads to the necessity of exploring other magnetic materials able to face the challenge better than the traditional ones. Bonded magnets have been used to replace sintered magnets, obtaining a better use of space and particular magnetic properties. Instead, for the magnetic circuit, Soft Magnetic Composites (SMC) allow realizing very complex magnetic design (3D path for flux) with iron loss reduction at medium-high frequencies, especially for the eddy currents loss contribution. On the other hand, SMC materials have such drawbacks as low mechanical properties and high hysteresis losses. For this reason, in this work, different studies considering several variables have been carried out. SMCs were produced through a moulding process; inorganic and organic layers to cover ferromagnetic particles were used, adopting different coating processes. Particu-lar tests have been performed for a quicker and more indicative overview of the materials ob-tained. The single sheet tester (SST) is easier than traditional toroidal methods; on the other hand, the multiplicity of variables affects the SMC materials and their process. For this reason, coercivity and conductibility tests permit rapid measurement and provide a direct classification of the produced SMCs, providing the main information needed to select suitable materials. Re-sults highlighted that choosing the more appropriate SMC material is possible after using these simple preliminary tests. After these tests, it was possible to argue that with 0.2 wt% of phenolic resin as the organic layer (and compaction pressure of 800 MPa), it is possible to produce a good SMC. On the other hand, the SMC with 0.2 wt% of epoxy resin (and compaction pressure of 800 MPa) gives a minor coercivity value. Additionally, despite the SMC with the inorganic layer, 0.2 wt% of nano-ferrites showing the best coercivity values (specifically for vacuum treatment at 600 °C), their resistivity was unsatisfactory

Feasibility Study of an Innovative Urban Electric-Hybrid Microcar

This paper presents the feasibility study of a new platform for electric-hybrid quadricycles, developed by addressing important concepts like passive safety and comfort, which often represent a shortcoming in this vehicle category. Starting from packaging of energy storage system and macroscopic subsystems as the main technological constraint, the study has been entirely developed in a virtual environment, with finite element verifications on preliminary models, and a subsequent cooperation phase between computer aided design and finite element analysis softwares, with a guideline for the main tests being that each could feasibly be carried out on a complete vehicle model in order to validate the original assumptions. The resulting design, with a body curb mass of less than 100 kg, was capable of integrating optimal static stiffness characteristics and crash performance, together with improved vehicle dynamics thanks to an innovative suspension archetype

Shear Strength Tests of a Glass-Ceramic Sealant for Solid Oxide Fuel Cells Applications

Different approaches are used for the integration of ceramic components in solid oxide fuel cells stacks, where dissimilar materials (ceramics and metals) have to be joined and coupled for a reliable long term operation. This work focuses on the mechanical characterisation of a glass ceramic sealant used for the joining of Crofer22APU metallic interconnect samples as well as the interaction with a preoxidised Crofer22APU. Crofer22APU–glass ceramic sealant joined samples are tested by two different mechanical tests. Hourglass samples with different geometries were tested using an in-house developed torsion test machine at room temperature. In addition, their mechanical strength was also evaluated according to the ISO 13124 standard. The comparison of the two different testing methods, with particular focus on the shear strength of the joined samples, are reviewed and discussed

Starfix lead extraction: Clinical experience and technical issues

AbstractTransvenous lead extraction (TLE) of the Starfix coronary sinus (CS) active-fixation lead may be challenging, due to undeployment of fixation lobes and venous occlusion. We report our experience in Starfix TLE, in comparison with previous data.A 78-year-old male, implanted in 2009 with Starfix lead, was referred to our institution for TLE, due to infective endocarditis with lead-associated vegetations. The tip of Starfix lead was located in distant, anterior position, in the great cardiac vein, close to patent left internal mammary artery-to-left anterior descending artery anastomosis, and first-choice surgical removal had a prohibitive operative risk.Conventional dilatation beyond CS ostium, as well as the use of a standard delivery catheter, was ineffective. An off-label modification of the delivery, by cutting the distal soft tip, was successful. However, the tip of the lead fragmented and was trapped in the innominate vein. Then a gooseneck snare grasped the fragment, allowing complete retrieval.TLE of Starfix leads may be particularly challenging, especially when its tip is located in a distant anterior location. In these cases, important help may be obtained by dilatation within the CS, by means of conventional or modified delivery catheters. Only experienced operators, sometimes with non-conventional techniques, should perform TLE of Starfix leads.<Learning objective: TLE of Starfix leads may be challenging, particularly when the tip is located in a distant anterior position. Dilatation with conventional tools may be precluded. In these cases modifications of the delivery catheters may be useful. Surgery should be avoided as first-choice procedure; only experienced operators, sometimes with non-conventional techniques, should perform TLE of Starfix leads.