METHODOLOGY AND MEANS OF OPERATIONAL MONITORING OF ELECTRIC MOTORS AT COMPRESSOR STATIONS

2019 ◽  
pp. 52-58
Author(s):  
A. B. Vasenin ◽  
S. E. Stepanov ◽  
O. V. Kryukov

The present technical condition of the fleet of electric motors serving the actuators of the infrastructure facilities of the fuel and energy complex is presented. The statistics of damage and damage from abnormal operation of electric drive units operating on mechanisms with a fan and pump load are given. The analysis of the causes of the increase in the range of vibration displacement, which leads to premature failure of electric motors, is given. A method for reliably determining the causes of damage, based on measuring and analyzing the electrical parameters of the harmonic spectrum of the motor current, is proposed. Its essence consists in creation of the universal diagnostic system working at the physical principle at which any indignations in work of an electric and mechanical part of the engine and related actuator lead to modulation of the consumed current. Existence in a range of current of characteristic frequencies of a certain size demonstrates existence of these or those damages. The device for its implementation includes phase current sensors of the supply voltage, a signal conditioner for normalizing and filtering signals, an analog-to-digital converter with a USB interface, and a controller with software for analyzing, evaluating, and diagnosing the condition. Experimental results have been obtained confirming the adequacy of the methodology and technical means for monitoring electric motors of various mechanisms.

2018 ◽  
Vol 69 (6) ◽  
pp. 418-421 ◽  
Author(s):  
Vojtech Petrucha ◽  
David Novotny

Abstract The article presents testing of a miniature fluxgate sensor developed and manufactured by Texas Instruments as well as an application of the sensor in a compact magnetic field probe with USB interface and LabView based software. Several basic properties of the sensor were evaluated and compared with the datasheet specifications. Offset stability measurements have indicated some possible problems for applications that require very high DC and low-frequency precision. Jumps in offset were present for some of the devices, frequency and duty of the jumps varying between individual pieces and with respect to the supply voltage. Magnetic probe for fast and handy measurements of DC and AC (up to 30 kHz) magnetic fields (up to ±1 mT) is also presented. The probe contains 24-bit analog to digital converter, microcontroller and high-speed USB interface which allows a live view of the signal in time and spectral charts. The probe proved to be very useful for the DRV425 debugging, application development, EMC measurements and magnetic field demonstrations activities.


Author(s):  
Ildar Yamansarin ◽  
◽  
Mikhail Salikov ◽  
Alexander Padeev ◽  
Dmitry Surkov ◽  
...  

The article deals with the issues related to the possibility of diagnosing the technical condition of an asyn-chronous electric motor by an external magnetic field. The justification of the problems associated with the di-agnosis of electric motors is given. The difficulties that arise when measuring the external magnetic field of electric motors, as well as the devices with which it is possible to carry out measurements, are described. The re-lationship between the EMF of the sensor and the external magnetic field is shown. The results of processing the EMF waveforms induced by an external magnetic field in an inductive sensor for various electric motors are presented. The processing was carried out by the fast Fourier transform method. The external magnetic field contains the first harmonic and various harmonics that are multiples of the combination of the stator teeth, or the sum of the stator and rotor teeth that fall on one pair of poles. The ratio of the amplitudes of the first and tooth harmonics is affected by the measurement location and the orientation of the sensor. Diagrams showing the ratio of the main and tooth harmonics at different points of the motor body are constructed. The depend-ences of the harmonic amplitudes on the magnitude of the magnetizing current of the stator are given. Changes in the amplitudes and spectrum of harmonics in the presence and absence of an inter-turn short circuit in the stator winding are shown. Diagrams of the circular external magnetic field for the main and higher harmonics are constructed. The study shows the possibility of using an external magnetic field to detect inter-turn short circuits of the stator winding.


Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2033
Author(s):  
Ahmed Elgreatly ◽  
Ahmed Dessouki ◽  
Hassan Mostafa ◽  
Rania Abdalla ◽  
El-sayed El-Rabaie

Time-based analog-to-digital converter is considered a crucial part in the design of software-defined radio receivers for its higher performance than other analog-to-digital converters in terms of operation speed, input dynamic range and power consumption. In this paper, two novel voltage-to-time converters are proposed at which the input voltage signal is connected to the body terminal of the starving transistor rather than its gate terminal. These novel converters exhibit better linearity, which is analytically proven in this paper. The maximum linearity error is reduced to 0.4%. In addition, the input dynamic range of these converters is increased to 800 mV for a supply voltage of 1.2 V by using industrial hardware-calibrated TSMC 65 nm CMOS technology. These novel designs consist of only a single inverter stage, which results in reducing the layout area and the power consumption. The overall power consumption is 18 μW for the first proposed circuit and 15 μW for the second proposed circuit. The novel converter circuits have a resolution of 5 bits and operate at a maximum clock frequency of 500 MHz.


2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Andre Luis Dias ◽  
Afonso Celso Turcato ◽  
Guilherme Serpa Sestito ◽  
Murilo Silveira Rocha ◽  
Dennis Brandão ◽  
...  

Abstract Electric motors are widely used in the industry. Several studies have proposed methods to detect anomalies in their operation, but always using sensors dedicated to this purpose. In this sense, this work aims to fill gaps in related works presenting a method for the detection of faults in rotating machines driven by electric motors in motion control applications using PROFINET network and PROFIdrive profile. The proposed method does not require any additional or dedicated sensors to provide data to the diagnostic system. Instead, the proposed methodology is based on the analysis of data transmitted in the communication network, which already exists for control purposes. Support vector machine (SVM) is used as a classifier of five different mechanical faults. The results provide that the methodology is feasible and efficient under different machine operating conditions, achieving, in the worst case, 97.78% efficiency.


2019 ◽  
Vol 29 (10) ◽  
pp. 2020005
Author(s):  
Hao Wang ◽  
Wenming Xie ◽  
Zhixin Chen

A novel area-efficient switching scheme is proposed for the successive approximation register (SAR) analog-to-digital converters (ADCs). The capacitor-splitting structure, charge-average switching technique, and [Formula: see text] (equal to [Formula: see text]/4) are combined together and optimized to realize the proposed switching scheme. [Formula: see text] is only used in the last two bit cycles, which affects the ADC accuracy little and reduces capacitor area by half. It achieves a 98% less switching energy and an 87.5% less capacitor area compared with the conventional switching method. In addition, the DAC output common-mode voltage is approximately constant. Thus, the proposed switching method is a good tradeoff among power consumption, capacitor area, DAC output common-mode voltage, and ADC accuracy. The proposed SAR ADC is simulated in 0.18[Formula: see text][Formula: see text]m CMOS technology with a supply voltage of 0.6[Formula: see text]V and at a sampling rate of 20[Formula: see text]kS/s. The signal-to-noise-distortion ratio (SNDR) and spurious free dynamic range (SFDR) are 58.2 and 73.7[Formula: see text]dB, respectively. The effective number of bits (ENOB) is 9.4. It consumes 42[Formula: see text]nW, resulting in a figure-of-merit (FoM) of 3.11 fJ/conversion-step.


2019 ◽  
Vol 124 ◽  
pp. 05001
Author(s):  
D.M. Valiullina ◽  
Yu.K. Ilyasova ◽  
V.K. Kozlov

This paper presents the results of a research of transformer oil in a visual way. The high information content of the optical radiation scattered and transmitted through the oil is shown. By the color of the radiation, it is possible to determine such characteristics of the oil as acid number, dielectric loss tangent, the presence of colloidal particles, their concentration and size, as well as the presence of aromatic compounds in the oil, changes in their molecular composition and concentration. By the presence of aromatic compounds and colloidal particles, it is possible to visually state the development of thermal and discharge defects in a transformer. This diagnostic system allows to assess the condition of power transformers without shutting them down, make decisions on their further operation without the use of expensive equipment and at the initial stage to identify the changes that are significant and necessary. This is due to the high cost of the transformer, its importance in terms of the reliability of power supply to consumers, the complexity of determining damages and defects at an early stage of development.


2014 ◽  
Vol 13 (01) ◽  
pp. 1450003
Author(s):  
Bhanupriya Bhargava ◽  
Pradeep Kumar Sharma ◽  
Shyam Akashe

In this paper, a correlated double sampling (CDS) technique is proposed in the design of a delta sigma analog-to-digital converter (ADC). These CDS techniques are very effective for the compensation of the nonidealities in switched-capacitor (SC) circuits, such as charge injection, clock feed-through, operational amplifier (op-amp) input-referred offset and finite op-amp gain. An improved compensation scheme is proposed to attain continuous compensation of clock feed-through and offset in SC integrators. Both high-speed and low-power operation is achieved without compromising the accuracy requirement. Also this CDS delta sigma ADC is the most promising circuit for analog to digital converter because this circuit reduces noise due to drift and low frequency noise such as flicker noise and offset voltage and also boosts the gain performance of the amplifier. Further, the simulation results of this circuit are verified on using a "cadence virtuoso tool" using spectre at 45 nm technology with supply voltage 0.7 V.


2021 ◽  
Vol 34 (04) ◽  
pp. 1431-1447
Author(s):  
Sergey G. Vesnin ◽  
Mikhail K. Sedankin ◽  
Lev M. Ovchinnikov ◽  
Alexander G. Gudkov ◽  
Vitaly Yu. Leushin ◽  
...  

This paper presents a new circuit of the miniature microwave radiometer for wearable devices, which can be used to monitor the core body temperature (CBT) of internal human tissues continuously 24/7. The measurement results of the proposed device, as opposed to the known miniature wearable radiometers, remain unchanged when the impedance of the examined area varies. We have derived an analytical expression for radiometer measurement error based on parameters of device components. This formula allows accuracies to be estimated and optimal parameters of the circuit to be selected to minimise measurement error at a design stage. It is shown that measurement error is independent of the antenna reflection coefficient and the temperature of the radiometer front-end. A prototype of the single-channel miniature radiometer has 32 х 25 х 14 mm3 dimensions and USB interface communication with PC. A 28-hour run of the device has shown that it is highly stable, and a maximum drift in temperature is 0.15 ̊C. Operating frequency range was 3400-4100 MHz, supply voltage - 5V; power supply of the radiometer in measurement mode is 210 mA; time constant of the radiometer without being averaged is 0.6 sec, at the same time, standard deviation δ = 0.17 ̊С, with further averaging during 4 sec δ=0.052 ̊С, with averaging during 30 sec δ =0.017 ̊C; when there were input reflections R2=0.25, an error in measuring brightness temperature shifted by 0.2 ̊ C; with 10 ̊C variations in ambient temperature the shift was 0.15 ̊C. Introduction of self-contained power supply and wireless communication with smartphone have made it possible to use the proposed radiometer as a wearable device to monitor the temperature of internal tissues and CBT during human activities.


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