scholarly journals GENERAL CALCULATION OF WINDING FACTOR FOR MULTI-PHASE/-LAYER ELECTRICAL MACHINES IRRESPECTIVE OF POLES NUMBER

2019 ◽  
Vol 59 (2) ◽  
pp. 153-161
Author(s):  
Daoud Ouamara ◽  
Frédéric Dubas ◽  
Sid Ali Randi ◽  
Mohamed Nadjib Benallal ◽  
Christophe Espanet
Keyword(s):  
Single Phase ◽  
Matrix Representation ◽  
Electrical Machines ◽  
Phase Layer ◽  
Rotor Design ◽  
The Matrix ◽  
New Feature ◽  
Multi Phase ◽  
Winding Factor ◽  
General Method

In this paper, a method to calculate the winding factor by only considering stator parameters without the rotor ones is developed. This is interesting because it allows the separation of the stator and rotor design, unlike the existing methods in the literature. A general method based on the matrix representation of a winding is presented. This approach requires the knowledge of four parameters : i) slots number, ii) phases number, iii) layers number, and iv) single-phase spatial distribution. A new feature of the multi-layer windings is introduced, it is called false-zero windings, which is divided into two categories: i) α-windings (i.e., odd false-zero windings), and ii) β-windings (i.e., even false-zero windings). The windings having no false-zero are categorized as γ-windings. The calculations are applied for single and multi-phase/-layer windings. The results of the comparison are satisfactory. The code used for the calculation is given in Appendix.

Cu-In and Cu-Zn-Sn Films as Precursors for Production of CuInSe2 and Cu2ZnSnSe4 Thin Films

2009 ◽  
Vol 1165 ◽  
Author(s):  
Olga Volobujeva ◽  
Enn Mellikov ◽  
Jaan Raudoja ◽  
Sergei Bereznev ◽  
Maris Pilvet
Keyword(s):  
Single Phase ◽  
Alloy Layer ◽  
High Quality ◽  
Cu Films ◽  
Island Type ◽  
Matrix Layer ◽  
The Matrix ◽  
Multi Phase ◽  
Metal Layers ◽  
Crystalline Matrix

AbstractThe co-sputtered Cu-In precursor layers were characterized by bi-layer surface structure in which island-type crystals were formed in a small-crystalline matrix layer. The elemental composition of the island-type crystals corresponds to the compound CuIn2 and the matrix (area) consists of copper-rich Cu11In9 phase. The surface morphology of sequentially evaporated Cu-Zn-Sn precursor layers is determined by the deposition order of stacked consistent metal layers. Precursor Mo-Sn-Zn-Cu films exhibit a well-formed “mesa-like” structure of the surface in which larger crystals (about 1,5 μm) are located on a “small-crystalline” valley. For films with other sequences of metallic layers, the mesa like structure is not so well exposed and well formed flat precursor layers were produced replacing separate metallic Cu and Sn layers with Cu/Sn alloy layer. Selenization of both Cu-In and Cu-Zn-Sn precursor layers begins with the formation of binary Cu-selenides with compositions varying with the temperature. At temperatures higher than 3700C the selenization of Cu-In results in single-phase CuInSe2 films in contrast to the selenization of Sn-Zn-Cu films that results always in multi-phase films consisting of high quality Cu2ZnSnSe4 crystals and of separate small-crystalline phase of ZnSe.

scholarly journals AUTOMATIC WINDING GENERATION USING MATRIX REPRESENTATION - ANFRACTUS TOOL 1.0

2018 ◽  
Vol 58 (1) ◽  
pp. 37 ◽  
Author(s):  
Daoud Ouamara ◽  
Frédéric Dubas ◽  
Mohamed Nadjib Benallal ◽  
Sid Ali Randi ◽  
Christophe Espanet
Keyword(s):  
Matrix Representation ◽  
Automatic Generation ◽  
Harmonic Spectrum ◽  
Electrical Machines ◽  
Generation Process ◽  
Magnetomotive Force ◽  
Research Software ◽  
Input Parameters ◽  
The Matrix ◽  
Original Approach

This paper describes an original approach dealing with AC/DC winding design in electrical machines. A research software called “ANFRACTUS Tool 1.0”, allowing automatic generation of all windings in multi-phases electrical machines, has been developed using the matrix representation. Unlike existent methods, where the aim is to synthesize a winding with higher performances, the proposed method provides the opportunity to choose between all doable windings. The specificity of this approach is based on the fact that it take only the slots, phases and layers number as input parameters. The poles number is not requested to run the generation process. Windings generation by matrix representation may be applied for any number of slots, phases and layers. The software do not deal with the manner that coils are connected but just the emplacement of coils in each slot with its current sense. The waveform and the harmonic spectrum of the total magnetomotive force (MMF) are given as result.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

The Work Hardening of Single Phase and Multi-Phase Aluminium Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 71-78 ◽  
Author(s):  
J. David Embury ◽  
Warren J. Poole ◽  
David J. Lloyd
Keyword(s):  
Work Hardening ◽  
Aluminium Alloys ◽  
Single Phase ◽  
Dynamic Recovery ◽  
Uniform Elongation ◽  
Strengthening Mechanisms ◽  
Plastic Response ◽  
Spring Back ◽  
Hardening Process ◽  
Multi Phase

The process of work hardening in aluminum alloys is important from the viewpoint of formability and the prediction of the properties of highly deformed products. However the complexity of the strengthening mechanisms in these materials means that one must carefully consider the interaction of dislocations with the detailed elements of the microstructure and the related influence of the elements on dislocation accumulation and dynamic recovery. In addition, it is necessary to consider the influence of the work hardening process at various levels of plastic strain. This permits the possibility of designing microstructure for tailored plastic response, e.g. not simply designed for yield strength but also considering uniform elongation, spring-back, ductility etc. This presentation will explore the concept of identifying the various interactions which govern the evolution of the work hardening and their possible role in alloy design.

Abstract 77: Ongoing Leakage Revealed by Second Phase Spot Sign Volume Expansion in Multi-Phase Computed Tomography Angiography Strongly Predicts Intracranial Hemorrhage Growth

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Abdulaziz Al Sultan ◽  
Ericka Teleg ◽  
MacKenzie Horn ◽  
Piyush Ojha ◽  
Linda Kasickova ◽  
...  
Keyword(s):  
Volume Expansion ◽  
Single Phase ◽  
Meta Analysis ◽  
Hematoma Expansion ◽  
Second Phase ◽  
Hematoma Volume ◽  
Spot Sign ◽  
Time Resolved ◽  
Multi Phase

Background: CTA spot sign is a predictor of intracerebral hemorrhage (ICH) expansion. This sign can fluctuate in appearance, volume, and timing. Multiphase CTA (mCTA) can identify spot sign through 3 time-resolved images. We sought to identify a novel predictor of follow up total hematoma expansion using mCTA. Methods: This cohort study included patients with ICH between 2012-2019. Quantomo software was used to measure total hematoma volume (ml) from baseline CT & follow-up CT/MRI blinded to spot sign in 3 mCTA phases. Spot sign expansion was calculated by subtracting 1 st phase spot sign volume from 2 nd phase spot sign volume measured in microliters. Results: 199 patients [63% male, mean age 69 years, median NIHSS 11, IQR 6-20] were included. Median baseline ICH volume was 16.1 ml (IQR 5-29.9 ml). Amongst all three mCTA phases, spot sign was best detected on the 2nd phase (23% vs 17.5% 1 st phase vs 22% 3 rd phase). In multivariable regression, spot sign expansion was significantly associated with follow up total hematoma expansion (OR: 1.03 per microliter of spot sign expansion, p=0.01). Figure 1 shows the predicted total hematoma expansion by spot sign expansion. mCTA spot sign had a higher sensitivity for predicting total hematoma volume expansion than single-phase CTA (reported in meta-analysis of 14 studies), 86% vs 53%, respectively, while both having similar specificity, 87% vs 88%, respectively. Conclusion: Spot sign expansion on mCTA is a novel predictor of total hematoma expansion and could be used to select patients for immediate therapeutic intervention in future clinical trials. Using mCTA improves sensitivity while preserving specificity over single-phase CTA.

MRHS solver based on linear algebra and exhaustive search

2018 ◽  
Vol 12 (3) ◽  
pp. 143-157 ◽  
Author(s):  
Håvard Raddum ◽  
Pavol Zajac
Keyword(s):  
Linear Algebra ◽  
Matrix Representation ◽  
Equation System ◽  
Exhaustive Search ◽  
Binary Matrix ◽  
Algebraic Attacks ◽  
The Matrix ◽  
Speed Up ◽  
Symmetric Key

Abstract We show how to build a binary matrix from the MRHS representation of a symmetric-key cipher. The matrix contains the cipher represented as an equation system and can be used to assess a cipher’s resistance against algebraic attacks. We give an algorithm for solving the system and compute its complexity. The complexity is normally close to exhaustive search on the variables representing the user-selected key. Finally, we show that for some variants of LowMC, the joined MRHS matrix representation can be used to speed up regular encryption in addition to exhaustive key search.

scholarly journals Modular Rotor Single Phase Field Excited Flux Switching Machine with Non-Overlapped Windings

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1576 ◽  
Author(s):  
Lutf Ur Rahman ◽  
Faisal Khan ◽  
Muhammad Afzal Khan ◽  
Naseer Ahmad ◽  
Hamid Ali Khan ◽  
...  
Keyword(s):  
Phase Field ◽  
Single Phase ◽  
Dead Zone ◽  
Optimization Technique ◽  
Rotor Design ◽  
Iron Losses ◽  
Excitation Coil ◽  
Electromagnetic Performance ◽  
Copper Losses ◽  
Single Phase Field

This paper aims to propose and compare three new structures of single-phase field excited flux switching machine for pedestal fan application. Conventional six-slot/three-pole salient rotor design has better performance in terms of torque, whilst also having a higher back-EMF and unbalanced electromagnetic forces. Due to the alignment position of the rotor pole with stator teeth, the salient rotor design could not generate torque (called dead zone torque). A new structure having sub-part rotor design has the capability to eliminate dead zone torque. Both the conventional eight-slot/four-pole sub-part rotor design and six-slot/three-pole salient rotor design have an overlapped winding arrangement between armature coil and field excitation coil that depicts high copper losses as well as results in increased size of motor. Additionally, a field excited flux switching machine with a salient structure of the rotor has high flux strength in the stator-core that has considerable impact on high iron losses. Therefore, a novel topology in terms of modular rotor of single-phase field excited flux switching machine with eight-slot/six-pole configuration is proposed, which enable non-overlap arrangement between armature coil and FEC winding that facilitates reduction in the copper losses. The proposed modular rotor design acquires reduced iron losses as well as reduced active rotor mass comparatively to conventional rotor design. It is very persuasive to analyze the range of speed for these rotors to avoid cracks and deformation, the maximum tensile strength (can be measured with principal stress in research) of the rotor analysis is conducted using JMAG. A deterministic optimization technique is implemented to enhance the electromagnetic performance of eight-slot/six-pole modular rotor design. The electromagnetic performance of the conventional sub-part rotor design, doubly salient rotor design, and proposed novel-modular rotor design is analyzed by 3D-finite element analysis (3D-FEA), including flux linkage, flux distribution, flux strength, back-EMF, cogging torque, torque characteristics, iron losses, and efficiency.

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