LOW-FREQUENCY ELECTROMECHANICAL VIBRATION CONVERTER BASED ON LEVITATION EFFECT

At present, one of the urgent problems in the energy and industry is to improve the reliability of the operation of various equipment. An effective method for increasing the reliability of equipment is diagnosing the state of machines and predicting their performance. Vibration control methods are widely used to diagnose rotary rotating machines. By the nature of the vibration process of the machine, it is possible to determine the degree of wear and, accordingly, the technical condition of the machines. In measuring technology for diagnostics of low-speed equipment with rotation frequencies of a unit of Hz, for example, hydroelectric generators of hydroelectric power plants, inertial electromechanical converters are used. The latest developments of such converters use an electromagnetic suspension with parametric feedback, which allows you to control the rigidity of the oscillatory system. However, for centering the moving part in electromechanical converters, flexible guides are used, which are sources of dry friction, which complicates the simulation of measurement processes and limits the sensitivity threshold to a minimum. In addition, flexible guides limit the frequency range of the converters. Currently, the most promising direction for solving this problem is the levitation effect, which allows you to completely exclude mechanical contact and, accordingly, reduce the sensitivity threshold of the transducer. From the analysis of literary sources, it follows that there are relatively few publications in this area. The proposed article provides an analysis of existing converters, on the basis of which a converter with improved characteristics, a measuring converter, is proposed. The proposed electromechanical converter has improved metrological characteristics and therefore can control and diagnose equipment in various fields of human activity. This problem is especially relevant in the hydropower industry.

Zastosowanie stanowiska pomiarowego do badań przewodnictwa cieplnego materiałów budowlanych metodą „gorącego drutu”

Results of experimental research have been presented in this article, determining the coefficient of thermal conductivity (λ) of gypsum. During measurements, a “hot wire” method was used, which belongs to the most interesting method because of its simplicity, easiness of realization and precision. Platinum Pt100 sensor was used during measurements, which both with measuring system creates precise temperature measuring converter with voltage output. Measurements were registered with the help of computer measuring system, with sampling time every 0.01 s.