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The wheel-flat defect is one of the many issues decreasing the level of and comfort in light rail vehicles. The two main causes of wheel-flats are temporary or complete wheel blocking. The negative effect is the increase of the dynamic phenomenons in the wheel-rail interaction, which are impulsive in their nature. It could prove to be dangerous for the safety of the ride. Therefore, a regular wheel surface monitoring and wheel-flats detecting would be well-founded to the fast detection of a flat point and to take remedial measures. The main aim of the article is to present the algorithm, according to which the wheel-flat detection during tram passage is possible. Several vibration transducers were mounted on the rail and measured vibration amplitude during trams pass-by. The proposed method is based on the vibration signal processing in the time and frequency domain. The Hilbert transform was used in the algorithm and all research analyses. The carried out experimental study and the analysis of the results of the method, show a high efficiency in the wheel flat detection. KeywordsTram, wheel-flat, Hilbert transform, envelope analysis Wheel-flat detection on trams using envelope analysis with Hilbert transform Tomasz Nowakowski et al.

Abstract. An optimal control theory based method is presented aiming at minimizing the energy delivered from source and the power loss in a stepper motor circuit. A linear quadratic current regulator with an infinite time horizon is employed and its appropriateness for this type of a problem explained. With the purpose of improving the accuracy of the control system, the self and mutual inductances of windings are calculated using a finite element model. The numerically computed results are verified experimentally.

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Many methods of diagnosing internal combustion engines have been already worked out. They can be divided into methods using working processes and methods using leftover processes. Working processes give information about general condition of internal combustion engine. Leftover processes give information about condition of particular subassemblies and kinematic couples; hence they are used as autonomous processes or as processes supporting other diagnostic methods. Methods based on analysis of vibrations and noise changes to determine technical condition of object are named as vibroacoustic diagnostics. In papers about vibroacoustic diagnostics of engine, problems connected with difficulty to select test point and to define diagnostic parameters containing essential information about engine's condition, are most often omitted. Selection of engine's working parameters and conditions of taking measurements or registering vibration signal are usually based on references, researcher's experience or intuition. General assumptions about taking measurements of signal closest to its source are most often used. Application of vibrations and noise generated by working combustion engine to assess correctness of its work and technical condition has many advantages. Vibroacoustic processes are a good carrier of diagnostic information for the following reasons: -high information capacity, -high speed of data transfer (signal's component describing change in object's condition is visible the moment the inefficiency occurs), -vibration signal reflects all significant processes in combustion engine, -measurement of vibrations and noise does not require special preparations of technical object for tests and can be carried out during regular operations. This article presents a new approach to vibroacoustic diagnostics of internal combustion

If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation.Abstract Presents 3D method for the computation of the winding current distribution and power losses of the electromagnetic gear. For a prescribed current obtained from measurement, the transient eddy current field is defined in terms of a magnetic vector potential and an electric scalar potential. From numerically obtained potentials the power losses are determined. The winding power losses calculation of an electromagnetic gear shows that a given course of the current generates skin effect and significantly changes the windings resistances. Also presents the designing method for reducing power losses.