We investigate the Schwinger pair creation process in the context of gravitational models with the back reaction of the electric field included in the geometry. The background is also an exact solution of type II superstring theory, where the electric field arises by Kaluza-Klein reduction. We obtain a closed formula for the pair creation rate that incorporates the gravitational back reaction. ...

Hultman, E. 2018. Robotized Production Methods for Special Electric Machines. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1608. 82 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-513-0177-8. A research project on renewable energy conversion from ocean waves to electricity was started at the Division of Electricity at Uppsala Unive...

Magnetic gear and magnetic-geared machine (MGM) are the potential solutions in electric vehicles (EVs) powertrains for inherent high efficiency mechanical simplification. However, torque density issue of MGM greatly limits its industrial application. To enhance performance MGM, a torque-enhanced with dual-series-winding design approach proposed. The key merits proposed to achieve space utilizat...

A hierarchical ordering is demonstrated for the periodic orbits in a strongly coupled multidimensional Hamiltonian system, namely the hydrogen atom in crossed electric and magnetic fields. It mirrors the hierarchy of broken resonant tori and thereby allows one to characterize the periodic orbits by a set of winding numbers. With this knowledge, we construct the action variables as functions of ...

A fundamental string with non-zero winding number can unwind in the presence of a Kaluza-Klein monopole. We use this fact to deduce the presence of a zero mode for the Kaluza-Klein monopole corresponding to excitations carrying H-electric charge and we study the coupling of this zero mode to fundamental strings. We also a describe a T-dual process in which the momentum of a fundamental string “...

We study the Dp-brane dynamics near NS5-branes with constant electromagnetic field. In the framework of effective Dirac-Born-Infeld action, we investigate the effect of the electromagnetic field on the Dp-brane dynamics. The radial motion of the Dp-brane on the transverse directions of NS5-branes can be mapped to a rolling tachyon in a constant NS Bμν background. In the near throat region, the ...

We study aspects of d-dimensional black holes with two electric charges, corresponding to fundamental strings with generic momentum and winding on an internal circle. The perturbative α corrections to such black holes and their gravitational thermodynamics are obtained. The latter are derived using the Euclidean approach and the Wald formula for the entropy. We find that the entropy and the cha...

Detecting and removing minor faults in power transformer winding is essential because minor faults may develop and lead to major faults and finally irretrievable damages occur. In this paper in order to detect the position of short-circuit in the winding, frequency response of the input impedance of a power transformer is analyzed. Common short-circuits are categorized and the results are compa...

Bearingless permanent magnet synchronous motor (BPMSM) has the characteristic of both conventional permanent magnet synchronous motor and traditional magnetic bearings. In this paper, the design and analysis of BPMSM by using Matlab/Simulink and ANSYS Maxwell are presented. The principle of electromagnetic force is utilized to ensure a stable levitation operation of BPMSM. The BPMSM mathematica...

The article substantiates the expediency of using a controlled electric motor in grinding mechanisms drives instead an unregulated asynchronous motor. problem facilitating start-up ball mills and ensuring accurate stop neck lowest speed is considered. As review literature showed, control two-speed motors simple, cheap reliable option. In many existing motors, two independent windings are placed...