Rotor Rings Research Articles

Bearing faults and broken bars simulation in an induction motor using an engineering tool

Industrial processes require reliable, safe, and continuous operation of electric motors. However, unexpected failures result in production losses, high emergency maintenance costs, damage to other related machines and prolonged shutdowns. Therefore, the development of failure analysis, detection and prevention systems is of high importance for the industrial sector. The following paper proposes the generation of a model of a squirrel cage induction motor in the software tool Simulink capable of simulating: i) broken bars and broken rotor rings, and ii) failures in the bearings of the motor, based on the Motor Current Signature Analysis (MCSA) technique which is a non-invasive method. Moreover, the Fast Fourier Transform (FFT) analysis is used to perform spectral investigation on the current to detect specific components that characterize faults in these conditions.

A novel modular designing for multi-ring flywheel rotor to optimize energy consumption in light metro trains

Abstract In this paper, a multi-ring flywheel rotor is chosen as a basic module for modular designing an optimized energy storage system to reduce the energy consumption in light metro trains by finding the best capacity and the number of optimized-flywheel rotor module for each train car. After finding the adequate capacity and optimizing the geometric characteristics of rotor rings, the effect of using the modular Flywheel energy storage system (FESS) on reducing the energy consumption of light urban trains is investigated. Four different rotors with various energy storage capacities are chosen, so that results can be used for a wide range of light trains with a power demand range of 1620–3420 kW. In the optimization algorithm, the energy per unit volume is considered as the cost function. The presented general modular designing is examined for Shiraz urban train system by using real-time speed and acceleration data. A three-layer flywheel with an energy storage capacity of 500W.h serves as a practical example. Finally, the effects of the number of passengers, peak, and off-peak hours in the energy storage capacity of the system are also studied. Using 15-FESS modules results in 35.1% energy saving for this line.

Substantiation of the parameters of short-circuited rings for integrated design of an asynchronous motor using quasi-three-dimensional field analysis and modeling

Purpose. To justify and apply an improved mathematical model of induction motors for solving problems of increasing their energy efficiency as part of electromechanical systems. To investigate the effect of increasing the cross-sectional area of the short-circuited rotor rings on the efficiency in the operating mode of the electromechanical system of the engine-mechanism, the multiplicity of starting current and torque. Methodology. The use of a refined mathematical model of the engine when integrating it into a simulation model of an electromechanical system that takes into account the nonlinear dependencies of the parameters of the equivalent circuit calculated from the results of a quasi-three-dimensional field analysis. Results. Originality. With reduced requirements for starting torque, it is reasonable to use an improved mathematical model of the engine when determining the parameters of the rings of a short-circuited rotor. Practical value. The effect of increasing the cross-sectional area of the short-circuited rotor rings on the engine operating and starting characteristics is investigated. The approximation dependences of the electromagnetic parameters as a function of the magnitude of the design parameters are substantiated.

The Gearbox of the Bacterial Flagellar Motor Switch

SummarySwitching of flagellar motor rotation sense dictates bacterial chemotaxis. Multi-subunit FliM-FliG rotor rings couple signal protein binding in FliM with reversal of a distant FliG C-terminal (FliGC) helix involved in stator contacts. Subunit dynamics were examined in conformer ensembles generated by molecular simulations from the X-ray structures. Principal component analysis extracted collective motions. Interfacial loop immobilization by complex formation coupled elastic fluctuations of the FliM middle (FliMM) and FliG middle (FliGM) domains. Coevolved mutations captured interfacial dynamics as well as contacts. FliGM rotation was amplified via two central hinges to the FliGC helix. Intrinsic flexibility, reported by the FliGMC ensembles, reconciled conformers with opposite FliGC helix orientations. FliG domain stacking deformed the inter-domain linker and reduced flexibility; but conformational changes were not triggered by engineered linker deletions that cause a rotation-locked phenotype. These facts suggest that binary rotation states arise from conformational selection by stacking interactions.

PERMANENT MAGNET THRUST BEARING: THEORETICAL AND EXPERIMENTAL RESULTS

This paper presents the design and analysis of permanent magnet (PM) thrust bearing made up of three ring pairs for flve degrees of freedom of the inner rings (rotor rings). The arrangement pattern of rings in PM bearing is considered in two ways: conventional structure and Halbach structure. The simplifled three dimensional (3D) mathematical models employing Coulombian approach and vector method are used to design the bearing. MATLAB codes are written to evaluate the axial force, stifiness and moments in both the structures for flve degrees of freedom, thereby the efiect of axial, radial and angular displacements of the rotor on the aforementioned characteristics is addressed. The results of the mathematical model are validated by the results of 3D Finite Element Analysis (FEA) and experiments. It is observed that, the conventional structure seems to be more sensitive to the angular displacement, as the percentage decrease in force and stifiness is more with respect to angular displacement than the Halbach structure. The efiect of angular displacement of the rotor on the performance of bearing in both the structures is crucial.

Stabilization of Fo/Vo/Ao by a radial electric field.

The membrane domain of rotary ATPases (Fo/Vo/Ao) contains a membrane-embedded rotor ring which rotates against an adjacent cation channel-forming subunit during catalysis. The mechanism that allows stabilization of the highly mobile and yet tightly connected domains during operation while not impeding rotation is unknown. Remarkably, all known ATPase rotor rings are filled by lipids. In the crystal structure of the rotor ring of a V-ATPase from Enterococcus hirae the ring filling lipids form a proper membrane that is lower with respect to the embedding membrane surrounding both subunits. I propose first, that a vertical shift between lumenal lipids and embedding outside membrane is a general feature of rotor rings and second that it leads to a radial potential fall-off between rotor ring and cation channel, creating attractive forces that impact rotor-stator interaction in Fo/Vo/Ao during rotation.

Optimal design of press-fitted filament wound composite flywheel rotors

This paper explores the design of press-fitted, cylindrical, filament wound composite flywheel rotor rims using two-dimensional plane stress anisotropic elasticity solutions and an optimization method based on simulated annealing. A method of accounting for residual stresses in press-fitted composite rims is proposed and demonstrated. The starting point for the designs is an open core rotator motor/generator with a pre-determined, fixed pair of concentric rotor rings, upon which several carbon/epoxy rings with different structural properties are press-fitted. For certain assumed sequences of carbon fiber types versus radius, optimal designs are determined with the objective of maximizing specific energy of the rotor subject to constraints defined by expected operating speeds and temperatures as well as material strengths. The optimal solutions suggest that specific energies of 40–50 W · h/kg and tip speeds of 800–900 m/s are feasible with 5–8 press-fitted carbon/epoxy rings.