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

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.

Deformation Behavior of a β-Solidifying TiAl Alloy within β Phase Field and Its Effect on the β→α Transformation

In this study, the deformation behavior of a Ti-40Al-10V (at.%) alloy within β single phase field was examined by means of isothermal compression at 1300 °C under strain rates of 2 s−1, 0.2 s−1, and 0.02 s−1, as well as its effect on the subsequent β→α transformation. The results showed that the alloy behaved steady-state flow with dislocation creep as the predominant rate-controlling process. Dynamic recrystallization (DRX) evidently occurred during deformation, and its volume fraction was dramatically increased so that at the lowest strain rate (0.02 s−1), a full-DRX β structure was obtained. The preferentially dynamic migration of grain boundaries with <100> orientation was demonstrated to be the major DRX mechanism. The texture was characterized by a <100> + <111> double-fiber at 2 s−1, but gradually transformed into a simple rotated cube orientationunder 0.02 s−1, accompanied by a decreasing texture intensity. During the subsequent β→α transformation, two types of α morphology wereproduced with evident variant selection, namely, the Widmannstatten colony and martensitic laths. Texture simulation revealed that the α texture was solely determined by parent β texture, despite of the variant selections.

Analytical Modeling of Austenite Growth and Phase Evolution during Reverse Transformation from Pearlite in High Carbon Steels

Based on an analytical one-dimensional model, austenite growth into pearlite lamella and the corresponding phase evolution during isothermal reverse transformation to austenite at 1000-1183 K in Fe-C fully pearlitic steels containing 0.6-1.0 mass% C (in the austenite single phase field of Fe-C phase diagram) were simulated. It was found that the rate of austenite growth into ferrite increases faster with increasing reversion temperature than into cementite. Three types of phase evolution dependent on reversion temperature and carbon content were classified: 1) cementite rather than ferrite disappears first; 2) ferrite and cementite simultaneously disappear; 3) ferrite rather than cementite disappears first. The type of phase evolution in a hypoeutectoid steel heated above its Ae3temperature possibly changes in the order of 1), 2) and 3) as the reversion temperature increases. For eutectoid and hypereutectoid steels, the phase evolution during isothermal reversion always obeys the type 3).

A New Algorithm of Phase Field Approach to Polycrystalline Dendritic Solidification in Two and Three Dimensions

A new algorithm of phase field model is developed to simulate polycrystalline dendritic solidification growth in undercooled melts. The algorithm adopts a single phase field order parameter model incorporated with the anisotropy of solid-liquid interfacial energy and mobility. The model validation is performed by comparing the simulations with the theory analytical results and experimental information for both single and multi-grain dendritic growth, which demonstrates the quantitative capabilities of the proposed algorithm.

Partial Pressure Differential and Rapid Thermal Annealing for Integrated Yttrium Iron Garnet (Yig)

In this work, magneto-optical garnets were grown monolithically by low-temperature reactive RF sputtering, followed by an ultra-short (< 15sec) anneal. It was found that in addition to low thermal budgets due to timing, the temperature required (< 750°C) for garnet crystallization was also reduced compared to standard tube furnace annealing (> 1000°C). MgO and fused quartz were used as substrates because they will be useful for future buffer layers and optical claddings. Y-Fe-O films were made with systematically varied compositions and the chemical, structural, and optical properties of the resulting films were analyzed. A solid solution single phase field for YIG was found that spanned a wide range of compositions (30.1 ∼ 49.0 atomic % of Fe). The resulting YIG quality was measured by vibrating sample magnetometry (VSM), X-ray diffraction (XRD), and measurements of Faraday rotation (FR). Although the XRD results showed that the films had isotropic crystallinity, the VSM indicated that shape anisotropy dominated the magnetic properties. Out of plane FR measurements yielded up to 0.2°/μm at 632nm rotations. This rotation will be higher in plane. All of these tests demonstrated that the YIG was comparable to YIG grown by standard annealing and also by in-situ crystallization.

Superconductivity in the (Nd,Ce,Ca)2Cuo4-Z System

We have controlled the carrier (electron) density in Nd2CuO2 of the T’ structure by introducing both Ce and Ca into the Nd‐sites, and studied the superconducting transition temperature versus carrier density relationship. The phase relations in the (Nd1‐x‐yCexCay)2CuO4‐z system were studied by means of powder X‐ray dirfractron and electron‐probe micro‐analysis techniques. For the phase diagram of the (Nd1‐x‐yCexCay)2CuO4‐z system, the single phase field of the T’ phase was established. Samples of the (Nd0.9‐yCe0.1Cay)2CuO4‐z system with compositions included in the single phase field were synthesized. The carrier density in these samples was varied by controlling the Ca content. The Hall effect and DC resistivity were measured to elucidate the relation between Tc and the carrier density.