Based on the rolling bearing vibration measurement principle in ISO standard, a nonlinear dynamic model of ball bearing is built and motion equations of the inner ring, outer ring, and rolling elements are derived by using Lagrange’s equation. The ball bearing model includes the influence of waviness, rotational speed, external load, arbor supporting stiffness and arbor eccentricity. Ball bearing high-speed vibration tests are performed and used to verify the theoretical results. Simulated results showed that specific waviness orders produced the principal frequencies that were proportional to rotational speed. Rotational speed mainly affected the value of the natural frequency of the bearing system, and RMS (Root Mean Square) of the full band had a great fluctuation with the increase of rotational speed. In the experiment, spectrum and RMS of 2fs-30 kHz (fs: the rotational frequency of inner ring/arbor) under high speed could include not only the influence of rotational speed but also principal frequencies produced by waviness, which could cover the part of requirements of the standard bearing vibration measurement.

The paper presents research on the development of a line-start synchronous reluctance motor (LSSynRM) and line-start permanent magnet synchronous motor (LSPMSM) based on components of a mass-produced three-phase low-power squirrel cage induction motor (IM). The aim of the research was to modify the squirrel cage rotor structure for which the best functional parameters characterizing the steady state of the LSSynRM and LSPMSM were obtained, while meeting the additional requirements for asynchronous start-up. Field-circuit models of the LSSynRM and LSPMSM have been developed in the professional finite element method (FEM) package, MagNet, and applied in the design and optimization calculations of the considered machines. Experimental testing on the designed LSSynRM and LSPMSM prototypes were carried out. The obtained results were compared with the performance of the reference IM. The conclusions resulting from the comparative analysis of these three motors are given and proposals for further work are discussed.

In Western music culture instruments have been developed according to unique instrument acoustical features based on types of excitation, resonance, and radiation. These include the woodwind, brass, bowed and plucked string, and percussion families of instruments. On the other hand, instrument performance depends on musical training, and music listening depends on perception of instrument output. Since musical signals are easier to understand in the frequency domain than the time domain, much effort has been made to perform spectral analysis and extract salient parameters, such as spectral centroids, in order to create simplified synthesis models for musical instrument sound synthesis. Moreover, perceptual tests have been made to determine the relative importance of various parameters, such as spectral centroid variation, spectral incoherence, and spectral irregularity. It turns out that the importance of particular parameters depends on both their strengths within musical sounds as well as the robustness of their effect on perception. Methods that the author and his colleagues have used to explore timbre perception are: 1) discrimination of parameter reduction or elimination; 2) dissimilarity judgments together with multidimensional scaling; 3) informal listening to sound morphing examples. This paper discusses ramifications of this work for sound synthesis and timbre transposition.