Development of the dual-channel frequency meter for measurements with hydrostatic pressure sensor

The paper describes the process and the results of development of the dual-channel frequency meter, which function is to measure the output frequency generated by bottom-mounted pressure sensors. The sensors are actively used to monitor the marine environment. AVR family microcontrollers were used as the computing core of the presented device. This solution allows to obtain far lower power consumption, which is especially important when operating with no industrial power supply system in the coastal zone. As a result, we can deploy a reliable monitoring equipment capable of long-term saving data and if necessary transmit it for further processing. The developed frequency-meter is able to continually record the ambient temperature, atmospheric pressure and dynamically varying output frequency, which depends on hydrostatic pressure (sea level). To obtain more accurate data, we implemented a frequency measure method called reciprocal counter with lower relative error not affected by value of the output frequency. A laboratory experiment has been conducted, which confirms the suitability of the developed frequency meter for field-oriented conditions.

Pengukuran level pembentukan es (ICING) pada pemodelan menggunakan rancang bangun sensor berbasis perubahan frekuensi dengan induktor datar

Icing is one of the main dangers for the flight and are cumulative. The icing is a process of accumulation of ice on parts of the aircraft, which will lead to changes in geometry and resulted in a variety of other disorders. For example, there was a buildup of ice on the propellor (propeller) and the engine carburetor so it can reduce the thrust plane even caused the plane to fall freely (stall). For it needs to be designed and built the Icing Detector as well as the actuator in providing early warning of the existence of the calculation and the icing on the pilot. This instrument is designed with electronic units that use the oscillator as frequency generator and frequency meter based mikrokontroller ATmega8 as the measuring frequency. The surface of the sensor is made up of printed inductor with a broad surface for detection area. Sensors and electronic units connected by cable. In addition, modeling for the pilot indicators have been designed using the LCD. Research results suggest that testing on "Ice Accretion-Level Measurement On Modelling using printed Inductor Sensor Prototype Based On Frequency Shifting" has been a successful made in accordance with the expected functions. These instruments can detect the occurrence of icing and give an indication of the thickness of the ice. It is possible to form a flat sensor installation on the aircraft to be more unobtrusive air flow, as well as a spacious surface produces more accurate results.

Evaluation of errors of the wattmeter method for determining magnetic losses in transformers

The problem of the influence of the accuracy of dividing magnetic losses into components in transformers on the efficiency of minimizing these losses is considered. Various methods of studying and evaluating the magnetic properties of electrical steels and the power of magnetic losses are described. It is shown that the use of the wattmeter method for determining the components of magnetic losses in a specific transformer, in contrast to the currently used methods for determining the power of specific magnetic losses, does not require special equipment and software. An assessment of two specific errors of the wattmeter method for determining the magnetic losses in the transformer core is carried out. The first error is associated with the errors of the measuring devices (wattmeter and frequency meter), the second – with electrical losses during an idle experiment. The dependences of the errors of these losses on the accuracy class of the devices (wattmeter and cymometer) are obtained. It was found that for a dry single-phase transformer, the error of hysteresis losses is 19 times higher than the accuracy class of devices, and the error of eddy-current losses is 32 times. For low-power transformers (up to 5 kVA), taking into account electrical losses in the no-load experiment underestimates the losses due to hysteresis and overestimates the losses due to eddy currents, the error in determining which can significantly exceed the total error in determining the magnetic losses. It is shown that for transformers with a capacity of over 25 kVA, the error associated with taking into account electrical losses in the no-load test is negligible.

The reproducibility of the 1hz gps in the aciclic displacement with intermittent intensity

Objective: the aim of this study was to verify the reproducibility index of the frequency meter with GPS technology with recording speed of 1Hz in acyclic displacement and intermittent intensity, performed by soccer referees. Materials and methods: it was characterized by a field study with a quantitative trait involving 14 men, aged 20.42 ± 2.78 years, from a barracks in the city of Rio de Janeiro. Polar heart rate monitor with 1Hz GPS model V800 was used. The protocol used was adapted from the FIFA test protocol for soccer referees, so that 10 "shots" of 75m in 15s were accomplished by 25m in 20 of recovery. Testing and retest were applied with 7 days interval and identical protocols: heating, ambiance (4 "shots" following the model of the protocol above) and then the test. Since the circuit covered in the test protocol was 1000 m.Results: a mean of 1002.5 ± 17.12 m was obtained in the test and in the test 1010.83± 32.88 m, the coefficients of variation were respectively 1% and 3%. The difference wasnot significant between the test and the retest (P-value> 0.05), and the intraclasscorrelation coefficient indicated a moderate association between the measures.Conclusion: therefore, it is suggested that it is acceptable to use a frequency gauge with a recording speed of 1Hz to monitor displacements of soccer referees in acyclic displacement and intermittent intensity.

Development of Alternating Current (AC) Line Monitoring Device for Power System Management

This work presents a study of the effect of imbalance between the supply of and demand of power from the National grid on electrical appliances. In the study, an alternating current (ac) line monitoring device was developed using arduino microcontroller to carry out the investigation. The device is a single system capable of measuring both the main frequency and nominal voltage of electricity supply. The device consists of seven major components: 12 V step-down transformer, half-wave rectifier, attenuator, wave-shaping circuit, arduino microcontroller, Liquid crystal display and micro SD card. The heart of the device is the arduino microcontroller that reads the period of the pulses from the shaping circuit and the output voltage from the scale resistor connected to the attenuator circuit in order to measure the levels frequency and voltage of the ac main source. By graphically compared the reading of the voltage obtained by the ac monitoring device with that of the standard Mastech voltmeter, it was shown that the device has a good correlation with the standard voltmeter with a deviation of ±0.21%, and this has proven that the device is capable of measuring ac voltage accurately. From the frequency test level results, it was found that the frequency measured by the device closely related to the frequency measured by the standard frequency meter. This shows that the device satisfied the requirement of the overall design. Hence, it can be used in the laboratory for demonstration and research purposes as well as in power plant industries. Keywords: Mains frequency, nominal voltage, half-wave rectifier, attenuator, wave-shaping circuit, Arduino microcontroller

Aspects of modernization of UA Ч3-101 frequency meter

JSC «Meridian» n. a. S. P. Korolyov at one point developed and mass-produced a wide-range microwave frequency meter of the 8-mm wavelength range UA Ч3-101. Over time, however, the device has become obsolete for a number of reasons, and the question arose of the need to replace it. Since the cost of foreign models of frequency meters with similar parameters available on the market is quite high, the enterprise’s capabilities in solving this issue were considered. The analysis showed that the development of a new similar frequency meter will also be quite expensive, but the modernization of the existing one might be much cheaper, since the enterprise has all the infrastructure for serial production of the upgraded frequency meter. This article describes technical solutions for the replacement of labor-consuming microwave components of the UA Ч3-101 frequency meter, such as microstrip and waveguide input microwave converters, as well as optimization of the frequency measuring process of the input signal, which allowed us to upgrade the device according to the requirements. The use of the developed broadband small-sized frequency converter in the modernized UA Ч3-101A frequency meter made it possible to simplify the circuit and the frequency measurement process as much as possible, to use only one input microwave converter, to significantly reduce the weight and size of the device, to abandon the labor-consuming and expensive waveguide components of the device, and to double the sensitivity upgraded frequency meter. The proposed technical solution allowed simplifying the production process of the frequency meter, making the device more convenient to use. In addition, due to the optimization of circuit and design solutions in the upgraded frequency meter, it was possible to combine the counter and the gate driver on the same board, combine the reference frequency block with a 100 MHz tunable generator, abandon the switch, which allowed reducing power consumption and increasing the reliability of the device.

Measurement of low frequency mechanical vibrations based on an inverted magnetic pendulum

<span>In this paper is presented the mathematical model, design and construction of a prototype of a vibration frequency meter in an adjustable range of 2 Hz to 30 Hz; The experimental results and their analysis are also presented, making a comparative evaluation with the theoretical model. The device is based on the principle of resonance applied in an inverted magnetic pendulum whose natural frequency can be modified by variations of physical parameters. The oscillation of the pendulum is recorded detecting variations in the magnetic field using hall effect sensors; the data recorded with a microprocessor is analyzed and the results are simultaneously plotted in a computer interface. The data obtained were processed to be plotted in the frequency domain, facilitating its analysis. It was proved that the prototype can be used as a frequency meter and that the adjustable character of the device works according to the mathematical model. Finally, The effect of the friction force was studied, it was concluded that the friction force affects the measurement after a considerable period of time of oscillation, but not in the first moments.</span>