A CFD software was employed to analyze the characteristics of the flat round porous aerostatic bearings. The effects of gap between the bearing and the guide way and the porosity of the porous material on the load capacity of the bearing were studied. The adequacy of the simulation model and the approach was verified. From the parametric study, it is found that the depth of the flow path does n...

Self-sensing magnetic bearings work without position sensors. The position measurement, which is required by the controller, can be deduced from the electromagnetic interaction between stator and rotor. The self-sensing method discussed in this paper is based on controlling the voltage over the coils and measuring the current through the coils. This method can be realized with a minimal amount ...

As critical systems are increasingly dependent on software and are connected to the Internet, insider threats will be of ongoing concern. For example, corrupt insiders could deliberately introduce malicious software into the organisation’s system to surreptitiously gain control, and launch online attacks via and against compromised systems. In this paper, we present a method that an insider can...

It is shown that ac discharges propagating at an air / dielectric interface, though of planar structure, behave, till a critical voltage Vcrit, as corona discharges in an air gap, with similar propagation fields for the filamentary discharge components and similar glow components. This leads to consider the surface discharges as gas discharges propagating above the dielectric surface. Beyond Vc...

A Finite Element Method (FEM) mesh is converted to a reluctance network through an original magnetostatic formulation based on face shape functions. This meshed reluctance network is coupled with an standard one, characterizing a 0D system. Both approaches are fully-compatible and the hybridized problem can be solve with a single circuit solver. The approach is tested in 2D on a magnetic circui...

Fluid slip has been observed experimentally in microand nanoscale flow devices by several investigators @e.g., Tretheway and Meinhart, Phys. Fluids 14, L9 ~2002!; Zhu and Granik, Phys. Rev. Lett. 87, 096105 ~2001!; Pit et al., Phys. Rev. Lett. 85, 980 ~2000!; and Choi et al., Phys. Fluids 15, 2897 ~2003!#. This paper examines a possible mechanism for the measured fluid slip, for water flowing o...

In the current study, a multi-arc predicting model for DC critical flashover voltage of iced and pre-contaminated long insulator strings under low atmospheric pressure is developed. The model is composed of a series of different polarity surface arcs, icicle-icicle air gap arcs, and residual layer resistance. The calculation method of the residual resistance of the ice layer under DC multi-arc ...

The air-gap of electrical machines may become non-uniform due to low accuracy of the manufacturing machinery, in assembling processes, or by aging. Detection and monitoring of this phenomenon is very important and of interest. There are several methods to model non-uniform air-gaps and to detect them by monitoring systems. One of the most widely used methods is by the analysis of the line curre...

This paper proposes a new technique of using Axial Flux Induction Machines (AFIMs) for wind energy conversion systems. The Power Generation by wind is found to be enhanced by using a Twin Rotor Axial Flux Induction Machine (TRAFIM). By using Axial Flux Induction Machines, the gear box ratio can be reduced. The Single air gap and TRAFIM have been mathematically modeled in the environment of MATL...

The authors proposed an electromagnetic harmonic movable tooth drive system which is an electromechanical coupled system where the coupled dynamics controls its overall operating behavior. However, the coupled dynamics of such a system was not found in the literature. In this paper, an electromechanical coupled dynamics equation of the flexible ring subjected to electromagnetic force is present...