Search results for "Mach"
showing 10 items of 3360 documents
Inverting Multiple Residual Stress Components from Multiple Cuts with the Contour Method
2007
An extension of the contour method is presented which allows the measurement of multiple stress components by making multiple cuts. In the contour method, a body is carefully cut in two using wire electric discharge machining (EDM). The contours, or shapes, of the cut surfaces are then measured and used to calculate the original residual stress normal to the cut plane using a simple finite element calculation. In the extension presented here, the two pieces from the original body can be cut again in a transverse direction, and the contours of the new cut surfaces are measured. The stresses calculated on the planes of these second cuts have been affected by the first cut. Then a simple inver…
Experimental Validation of a Novel Method for Harmonic Mitigation for a Three-Phase Five-Level Cascaded H-Bridges Inverter
2019
In modern high-power electrical drives, the efficiency of the system is a crucial constraint. Moreover, the efficiency of power converters plays a fundamental role in modern applications requiring also a limited weight, such as the electric vehicles and novel more electric aircraft. The reduction of losses pushes for systems with a dc bus and a high number of dc/ac converters, widespread in the vehicle, not burdened by a too expensive data processing system. The purpose of this article is to concur to reduce losses by proposing an innovative selective harmonic mitigation method based on the identification of the working areas where the reference harmonics present lower amplitudes. In partic…
Design and Test of a Thermomagnetic Motor Using a Gadolinium Rotor
2013
This paper presents a Thermomagnetic Motor, whose design of the motor is based on a thermal-magnetic coupled dynamic model, which models its magnetic as well thermal properties (magnetic permeability and thermal conductivity). The thermal processes are supposed to be influenced by the thermal conductivity, the convection and the advection. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal and geometrical parameters of the generated torque is given. A design of a machine, based on this theory is proposed and the related performances are numerically simulated. An experimental verification of the performances is reported.
A dq axis theory of the magnetic, thermal, and mechanical properties of Curie motor
2011
A dq axis theory of a thermomagnetic Curie motor is presented. This theory allows one to estimate the performances of a Curie motor from its geometrical, magnetic, and thermal properties. The proposed approach shows that the thermomagnetic Curie motor is equivalent from a magnetic point of view to a dc electric machine. The physical meaning of the parameters used in the dq theory of Curie motor is explicated. The theory is validated by using experimental data.
The use of results of spectral analysis of synchronous generator output voltage for technical diagnostics.
2006
The method of technical diagnostics of ship diesel engine-generator installations is offered. Spectral-power diagnostic parameters of the synchronous generator voltage and currents are used. The electric machine in this case is the multipurpose sensor of diagnostic parameters. On these parameters it is possible to judge quality of course of working processes in diesel engine cylinder, its technical condition. This method is applicable to piston compressor installations with the electric drive.
New approach to characterisation of electric alloys under rotating magnetic flux density
1996
The computation of electrical machines using the characterisation of electric alloys proposed by several authors gives performances not verified by experiments on actual machines. By means of finite-element-method software, the authors show that the electromagnetic context where electrical alloys are built into rotating electrical machines is completely different from the actual characterisation system. A new testing device is proposed to take into account the phenomena highlighted.
Equivalent circuit analysis of solid-rotor induction machines with reference to turbocharger accelerator applications
2006
Theoretical, numerical and experimental studies are described that have been carried out to develop a solid-rotor induction machine design for a particularly demanding application as an accelerator drive for a diesel engine turbocharger. In this application the turbo-motor will be required to operate at speeds of up to 130 000 rpm and in temperatures that can exceed 200°C. The results show that the equivalent circuit gives predictions that are of sufficient precision for design purposes and provides a useful design tool. It is shown that the use of a solid rotor affects the value of the stator leakage reactance and influences the motor performance through this effect as well as by presentin…
D-Q axis theory of thermomagnetic Curie motor
2010
This paper presents a the d-q axis theory of a thermomagnetic Curie motor. From this theory a maximization procedure of the performances of Curie motor has been developed. The proposed approach has shown that the thermomagnetic Curie motor is equivalent from a magnetic point of view to a d.c. electric machine. Consequently, a design of a Curie motor has been proposed and the calculated performances show a significant improvement in comparison to the performances reported in literature.
Analysis of magnetohydrodynamic generator driven by thermoacoustic engine for deep Space applications
2020
This paper discusses the results of theoretical and experimental investigation of magnetohydrodynamic generator with liquid metal working body. This electric machine is used to convert mechanical energy, supplied by thermoacoustic engine, to an AC form of electrical energy. The purpose of this technology is an electricity production in deep Space, potentially suitable for long term missions far away from Sun.
Dynamic Preisach Hysteresis Model for Magnetostrictive Materials for Energy Application
2013
In this paper the magnetostrictive material considered is Terfenol-D. Its hysteresis is modeled by applying the DPM whose identification procedure is performed by using a neural network procedure previously publised [. The neural network used is a multiplayer perceptron trained with the Levenberg-Marquadt training algorithm. This allows to obtain the Preisach distribution function, without any special conditioning of the measured data, owing to the filtering capabilities of the neural network interpolators. The model is able to reconstruct both the magnetization relation and the Field-strain relation. The model is validated through comparison and prediction of data collected from a typical …