leads and windings due t o eddy cu r ren t s induced in the conductors by t h e al ternat ing magnetic field. The leads and windings a r e connected in series, therefore, t he high-frequency resistance of t he transformer R t is An accurate, analyt ical method is proposed f o r calculating the lead and winding high-frequency resistance of complex transformer constructions. High-frequency resist...

A process model was developed for the fabrication of closed shape composite structures such as thick-wall cylinders, with the emphasis on fiber bundle deformation and its effect on the process physics. A continuum mechanics model for fiber bundle deformation in the composite manufacturing processes was proposed. Based on this model, the winding and consolidation processes for thick wall cylindr...

Hanne Jussila Concentrated Winding Multiphase Permanent Magnet Machine Design and Electromagnetic Properties – Case Axial Flux Machine Lappeenranta 2009 119 p. Acta Universitatis Lappeenrantaensis 374 Diss. Lappeenranta University of Technology ISBN 978-952-214-882-7, ISBN 978-952-214-883-4 (PDF), ISSN 1456-4491 Concentrated winding permanent magnet machines and their electromagnetic properties...

A reliable and accurate diagnosis of inter-turn short circuit faults is a challenging problem in the area of fault diagnosis of electrical machines. The purpose of this challenge is to be more efficient in fault detection and to provide a reliable method with low-cost sensors and simple numerical algorithms which not only detect the occurrence of the fault, but also locate its position in the w...

Conjugate heat transfer problem of a disc winding in a power transformer is studied using commercial CFD software. The study is done for oil flow, temperature distribution, hot spot location and temperature of the winding, for three different cases: first, no oil leakage past the top washer; second, partial leakage due to a 2 mm gap between the top oil guiding washer and cylindrical pressboard;...

This paper presents the influences of winding magneto-motive force (MMF) harmonics on the torque characteristics in surface-mounted permanent magnet vernier (SPMV) machines. Based on the magnetic gearing effects, the armature magnetic field of the SPMV machines is modulated by flux modulation poles (FMPs). In the modulated magnetic field, a working harmonic which corresponds to the number of th...

This paper investigates the behavior of a vectorcontrolled, fault-tolerant, permanent magnet motor drive system adopting a vertically placed strip winding (VSW) which can limit inter-turn short-circuit (SC) fault current to its rated value regardless of the position in the slot containing the shorted turns. The drives’ dynamic behavior is simulated using a per-phase equivalent circuit model wit...

Monitoring of winding faults is the most important item used to determine the maintenance status of a transformer. Commonly used methods for winding-fault diagnosis require the transformer to exit operation before testing and an external exciting signal, whether the transformer is malfunctioning or not. However, if an overvoltage signal can be regarded as a broadband excitation source for fault...

We study single-texture collapse using a leapfrog discretization method on a 30X30X30 spatial lattice. We investigate the influence of boundary conditions, physical size of the lattice, type of space-time background (flat, i.e., nonexpanding, vs radiation-dominated and matter-dominated universes), and spatial distribution of the initial texture configuration on collapse time and critical windin...

Frequency response analysis (FRA) is a method which is used to detect mechanical faults in transformers. The FRA response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. If there are any mechanical changes in the transformer, for example if the windings are moved or distorted, its fingerprint will also be changed...