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• Time Domain Analysis and Spectral Methods for Determining Rotational Speed of Rotary Machines

  1-8.

  Gábor Gárdonyi

  Krisztián Samu

  Views:

  72

  Accurate estimation of rotational speed of rotary machines has usually high priority in technical applications. This information should be calculated for many diagnostic algorithms, control or regulation processes. Incorrectly estimated values could occur serious disturbances in the operation of machines. Additional instrumentation often may be obstructed due to lack of space, but the construct of the machine may also affect the accuracy of measurement. In such cases, vibration diagnostic tools can be the disposal of difficulty. Mounting an acceleration sensor onto the outer surface of the measured device is not a major challenge. In most cases using time, frequency or quefrency domain analysis, it is possible to estimate the rotational speed of the analysed rotary machine. The calculated spectra and cepstra can help to determine the rotational speed more easily and more accurate than the time domain methods. This paper presents the comparison of these methods in terms of their usability and rotational speed estimation accuracy. A possible error of traditional optical measurement due to misalignment and benefits of the other methods are illustrated in this article via measured data series of a Brushless DC (BLDC) motor driven system.

• Technological Solutions to Compensate Humanmeteorological Measurement Errors with Measuring Human Activity and Movement

  1-7.

  Ádám Pintér

  Krisztián Samu

  Views:

  61

  To enhance the objectivity of humanmeteorological measurements, various instrumental measurements are required. These equipments are suitable to explore the desired relationships, only if those are able to record simultaneously the individual's physiological and micro-environmental parameters and their transients. It is also important to possibly filter or measure the disturbances effecting our measurements in order to compensate errors in our results. In our case this factor is the physical activity of the individual, which has effect on physiological parameters, therefore we have to register its value in function of time. The following paper deals with technical and theoretical questions of measuring this factor and summarizes the ascertainment we collected during the experiments. The topic is an integral part of teh PhD research Á. Pintér behooves at Budapest University of Technology and Economics.