Drying module is a part of any modern gas analysing device. Using the Peltier elements for cooling the gas probe in druying module is a known technical solution. Peltier elements are very energy-intensive things. So the task of calculation of amount of electrical energy which is needed for predetermined temperature decline of gas probe is very topical. The solution of this task is given in the article. With formulas for partial pressure of vapour we can calculate the humidity of gas at the output of drying module. Then we can find the temperature of gas. Finally using the heat balance equation and nomogramms we can calculate the voltage for Peltier element.
Keywords: Peltier element, gas probe, drying process, gas analyzer, heat balance, partial pressure of vapour
The article is devoted to the experimental investigation of the influence of load regimes on the spectrum of induction motor current . Spectrogram analysis allows to identify the presence of deterioration and to determine the operating mode of the induction motor. The experimental apparatus described in the paper allows to measure motor current oscillogram and calculate its spectrum. The appratus is based on PIC highspeed microcontroller. For current measuring the Hall sensor ACS712 is used. Several experiments are carried out in the research: without load, with load, with shaft beating imitaion. The analys of collected data has shown that the spectrums has some differences depends on the type of motor load. The research may be used for diagnostic system for inductor motors.
Keywords: Induction motor, current sensor, microcontroller, current spectrum, fast Fourier transform.
The experiments by obtaining 3-phase stator current oscillograms under different emergency regimes are described in article. For this purpose an experimental equipment has been used. It included current sensor, multi-channel ADC board, special block for emergency regime simulation and computer. For data processing MathCAD soft has been used. With Fast Fourier Transform algorithm the spectrum graphs were built. Analyse of spectrums showed the differences in odd harmonics between ordinary and any of emergency regime. For analyse the 0-1 kHz frequency range was taken. The research has shown that this technique can be used in diagnostics of 3-phase motors. General algorithm for real-time diagnostic system is developed.
Keywords: Three-phase induction motor, the current sensor, spectral analysis, harmonic, fast Fourier transform
The research of influence of periodical signal discontinuity on spectrum form is considered in the article. The numerical modeling of the system of discontinuous signals is performed. The spectrum of the system built from time discreet sampling is analyzed. The plots of the sample correlation coefficient between spectrums of continuous and discontinues signals are shown in the article. The research is needed for the development of digital measuring system for quartz plates frequency detecting.
Keywords: amplitude signal spectrum, discontinuous signal, quartz plates