scholarly journals Adaptive Scheme for Detecting Induction Motor Incipient Broken Bar Faults at Various Load and Inertia Conditions

Sensors ◽  
2022 ◽  
Vol 22 (1) ◽  
pp. 365
Author(s):  
Mohamed Esam El-Dine Atta ◽  
Doaa Khalil Ibrahim ◽  
Mahmoud Gilany ◽  
Ahmed F. Zobaa
Keyword(s):  
Main Idea ◽  
Threshold Value ◽  
Operating Conditions ◽  
Noisy Environment ◽  
Noisy Environments ◽  
Variable Loading ◽  
Protection Scheme ◽  
Stator Current ◽  
Fault Severity ◽  
Frequency Components

This paper introduces a novel online adaptive protection scheme to detect and diagnose broken bar faults (BBFs) in induction motors during steady-state conditions based on an analytical approach. The proposed scheme can detect precisely adjacent and non-adjacent BBFs in their incipient phases under different inertia, variable loading conditions, and noisy environments. The main idea of the proposed scheme is monitoring the variation in the phase angle of the main sideband frequency components by applying Fast Fourier Transform to only one phase of the stator current. The scheme does not need any predetermined settings but only one of the stator current signals during the commissioning phase. The threshold value is calculated adaptively to discriminate between healthy and faulty cases. Besides, an index is proposed to designate the fault severity. The performance of this scheme is verified using two simulated motors with different designs by applying the finite element method in addition to a real experimental dataset. The results show that the proposed scheme can effectively detect half, one, two, or three broken bars in adjacent/non-adjacent versions and also estimate their severity under different operating conditions and in a noisy environment, with accuracy reaching 100% independently from motor parameters.

scholarly journals Fault Detection in DC Microgrids Using Short-Time Fourier Transform

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 277
Author(s):  
Ivan Grcić ◽  
Hrvoje Pandžić ◽  
Damir Novosel
Keyword(s):  
Fourier Transform ◽  
Fault Detection ◽  
Operating Conditions ◽  
Time Signal ◽  
Short Time Fourier Transform ◽  
Dc Microgrid ◽  
Protection Scheme ◽  
Simulink Model ◽  
Battery Energy ◽  
Short Time

Fault detection in microgrids presents a strong technical challenge due to the dynamic operating conditions. Changing the power generation and load impacts the current magnitude and direction, which has an adverse effect on the microgrid protection scheme. To address this problem, this paper addresses a field-transform-based fault detection method immune to the microgrid conditions. The faults are simulated via a Matlab/Simulink model of the grid-connected photovoltaics-based DC microgrid with battery energy storage. Short-time Fourier transform is applied to the fault time signal to obtain a frequency spectrum. Selected spectrum features are then provided to a number of intelligent classifiers. The classifiers’ scores were evaluated using the F1-score metric. Most classifiers proved to be reliable as their performance score was above 90%.

scholarly journals Manufacturing, Characterisation and Mechanical Analysis of Polyacrylonitrile Membranes

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2378
Author(s):  
Mertol Tüfekci ◽  
Sevgi Güneş Durak ◽  
İnci Pir ◽  
Türkan Ormancı Acar ◽  
Güler Türkoğlu Demirkol ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Main Idea ◽  
Mechanical Analysis ◽  
Operating Conditions ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Load Carrying ◽  
The Impact ◽  
Static Behaviour ◽  
Modelling Process

To investigate the effect of polyvinylpyrrolidone (PVP) addition and consequently porosity, two different sets of membranes are manufactured, since PVP is a widely used poring agent which has an impact on the mechanical properties of the membrane material. The first set (PAN 1) includes polyacrylonitrile (PAN) and the necessary solvent while the second set (PAN 2) is made of PAN and PVP. These membranes are put through several characterisation processes including tensile testing. The obtained data are used to model the static behaviour of the membranes with different geometries but similar loading and boundary conditions that represent their operating conditions. This modelling process is undertaken by using the finite element method. The main idea is to investigate how geometry affects the load-carrying capacity of the membranes. Alongside membrane modelling, their materials are modelled with representative elements with hexagonal and rectangular pore arrays (RE) to understand the impact of porosity on the mechanical properties. Exploring the results, the best geometry is found as the elliptic membrane with the aspect ratio 4 and the better RE as the hexagonal array which can predict the elastic properties with an approximate error of 12%.

Online Speed Detection of Induction Motors Based on Tooth Harmonic

2011 ◽  
Vol 58-60 ◽  
pp. 2517-2521
Author(s):  
Qing Xin Zhang ◽  
Hai Bin Li ◽  
Jin Li
Keyword(s):  
Induction Motors ◽  
Rotor Speed ◽  
Motor Speed ◽  
Stator Core ◽  
Current Harmonic ◽  
Stator Current ◽  
Speed Measurement ◽  
Frequency Components ◽  
Air Gap Magnetic Field ◽  
Alveolar Surface

Many methods have been used to detect the motor speed. All of these methods are based on the parameter equation of motor and the detection results are influenced by parameters of induction motor more or less. The research of Speed Measurement method without of Motor parameters effect is very significant. Based on the harmonic generated in the air gap magnetic field by the stator core on the alveolar surface, directly by the analysis and testing of stator current harmonic, the rotor speed is detected which is proportional to the speed of frequency components. Experiment results show that this method is good, and the accuracy achieve a desired effect in real time.

Fault Detection of Electric Motors Application Using ML Estimation Method

2012 ◽  
Vol 591-593 ◽  
pp. 1958-1961
Author(s):  
Juggrapong Treetrong
Keyword(s):  
Fault Detection ◽  
Estimation Method ◽  
Load Condition ◽  
Fault Analysis ◽  
Electric Motors ◽  
Ml Estimation ◽  
Stator Current ◽  
Fault Severity ◽  
Severity Levels ◽  
Stator Fault

This paper proposes a new method of motor fault detection. ML Estimation is proposed as a key technique for signal processing. The stator current is used data for motor fault analysis. ML Estimation is generally applied to estimate signals for nonlinear model. The expectation is that the method can provide information for fault analysis. The method is tested on 3 different motor conditions: healthy, stator fault, and rotor fault motor at full load condition. Based on experiments, the method can differentiate conditions clearly and be also able to measure fault severity levels.

Asphaltene Mitigation in Giant Carbonate Abu Dhabi Fields: A Techno-Economic Comparison Between Continuous Injection and Formation Squeeze

2021 ◽  
Author(s):  
Mark Grutters ◽  
Sameer Punnapala ◽  
Dalia Salem Abdallah ◽  
Zaharia Cristea ◽  
Hossam El Din Mohamed El Nagger ◽  
...  
Keyword(s):  
Cost Effective ◽  
Threshold Value ◽  
Field Trials ◽  
Mitigation Strategy ◽  
Operating Conditions ◽  
Mitigation Strategies ◽  
Production Cycle ◽  
Asphaltene Precipitation ◽  
Coiled Tubing ◽  
Continuous Injection

Abstract Asphaltene deposition is a serious and re-occurring flow assurance problem in several of the ADNOC onshore oilfields. Fluids are intrinsically unstable with respect to asphaltene precipitation, and operating conditions are such that severe deposition occurs in the wellbore. Wells in ADNOC are generally not equipped with downhole chemical injection lines for continuous inhibition, and protection of the wells require frequent shut-in and intervention by wireline and coiled tubing to inspect and clean up. Since some of the mature fields are under EOR recovery strategies, like miscible hydrocarbon WAG and CO2 flood, which exacerbates the asphaltene precipitation and deposition problems, a more robust mitigation strategy is required. In this paper the results of two different mitigation strategies will be discussed; continuous injection of asphaltene inhibitor via a capillary line in the tubular and asphaltene inhibitor formation squeeze. Three asphaltene inhibitors from different suppliers were pre-qualified and selected for field trial. Each inhibitor was selected for a formation squeeze in both one horizontal and one vertical well, and one of the inhibitors was applied via thru-tubing capillary string. The field trials showed that continuous injection in remote wells with no real-time surveillance options (e.g. gauges, flow meters) is technically challenging. The continuous injection trial via the capillary string was stopped due to technical challenges. From the six formation squeezes four were confirmed to be effective. Three out of fours squeezes significantly extended the production cycle, from approximately 1.4 to 6 times the normal uninhibited flow period. The most successful squeezes were in the vertical wells. The results of the trial were used to model the economic benefit of formation squeeze, compared to a ‘do-nothing’ approach where the wells are subject to shut-in and cleanup once the production rates drop below a threshold value. The model clearly indicates that the squeezes applied in ADNOC Onshore are only cost-effective if it extends the normal flow period by approximately three times. However, a net gain can be achieved already if the formation squeeze extends the flow cycle by 15 to 20%, due to reduction of shut-in days required for intervention. Therefore, the results in this paper illustrate that an asphaltene inhibitor formation squeeze can be an attractive mitigation strategy, both technically and economically.

Proportional Integral Estimator of the Stator Resistance for Direct Torque Control Induction Motor Drive

2017 ◽  
Vol 8 (4) ◽  
pp. 1631
Author(s):  
Jagdish Gangadharrao Chaudhari ◽  
Sanjay Bhauraoji Bodkhe ◽  
Mohan V. Aware
Keyword(s):  
Induction Motor ◽  
Estimation Error ◽  
Direct Torque Control ◽  
Estimation Method ◽  
Operating Conditions ◽  
Torque Control ◽  
Proportional Integral ◽  
Stator Current ◽  
Current Estimation ◽  
Stator Resistance

In this paper, an improved proportional integral stator resistance estimation for a direct torque controlled induction motor is proposed. This estimation method is based on an on-line stator resistance correction regarding the variations of the stator current estimation error. In fact, the input variable of the PI estimator is the stator current estimation error. The main idea is to tune accurately the stator resistance value relatively to the evolution of the stator current estimation error gradient to avoid the drive instability and ensure the tracking of the actual value of the stator resistance. But there is an unavoidable steady state error between the filtered stator current modulus and its estimated value from the dq model of the machine which is due to pseudo random commutations of the inverter switches. An offset has been introduced in order to overcome this problem, for different speed command values and load torques. Simulation results show that the proposed estimator was able to successfully track the actual value of the stator resistance for different operating conditions

Comparative investigations on COD-removal in sequencing batch reactors and continuous flow plants

2001 ◽  
Vol 43 (3) ◽  
pp. 45-52 ◽  
Author(s):  
T. Dockhorn ◽  
N. Dichtl ◽  
R. Kayser
Keyword(s):  
Removal Efficiency ◽  
Municipal Wastewater ◽  
Plug Flow ◽  
Main Idea ◽  
Operating Conditions ◽  
Cod Removal ◽  
Batch Reactors ◽  
Mixing Characteristics ◽  
Hydraulic Load ◽  
The Individual

Investigations on enhanced COD removal from municipal wastewater were performed over a period of 2.5 years, comparing three different types of reactor. The main idea was to determine the influence of the mixing characteristics of the reactor on the treatment processes and the effluent quality. Therefore three pilot plants (a completely mixed reactor, a cascade of three reactors and a SBR) were operated under equal conditions (wastewater, hydraulic load, temperature, sludge age) in parallel to each other. Investigations were carried out at different sludge ages. It could be shown that within one sludge age the CODf removal efficiency increased, when mixing characteristics came closer to the plug flow and it also increased with higher temperatures. A significant correlation was observed between the COD removal efficiency and the sludge load. The higher the sludge load was the greater the CODf concentration in the effluent. Especially the SBR reactor showed an excellent performance under the given operating conditions. Dynamic simulation calculations were carried out, to investigate whether the influence of the type of reactor on the COD-elimination could be described theoretically by combining growth kinetics and the mixing characteristics of the individual reactors. The results showed that performance was better when mixing characteristics came closer to plug flow.

Delayed Hydride Cracking Initiation at Notches in Zr-2.5Nb Alloys

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Jun Cui ◽  
Gordon K. Shek ◽  
D. A. Scarth ◽  
Zhirui Wang
Keyword(s):  
Hydrogen Diffusion ◽  
Process Zone ◽  
Notch Root ◽  
Threshold Value ◽  
Operating Conditions ◽  
Test Results ◽  
Pressure Tubes ◽  
Delayed Hydride Cracking ◽  
Notch Tip ◽  
Hydride Cracking

Delayed hydride cracking (DHC) is an important crack initiation and growth mechanism in Zr-2.5Nb alloy pressure tubes of CANDU nuclear reactors. DHC is a repetitive process that involves hydrogen diffusion, hydride precipitation, growth, and fracture of a hydrided region at a flaw tip. In-service flaw evaluation requires analyses to demonstrate that DHC will not initiate from the flaw. The work presented in this paper examines DHC initiation behavior from V-notches with root radii of 15 μm, 30 μm, and 100 μm, which simulate service-induced debris fretting flaws. Groups of notched cantilever beam specimens were prepared from two unirradiated pressure tubes hydrided to a nominal hydrogen concentration of 57 wt. ppm. The specimens were loaded to different stress levels that straddled the threshold value predicted by an engineering process-zone (EPZ) model, and subjected to multiple thermal cycles representative of reactor operating conditions to form hydrides at the notch tip. Threshold conditions for DHC initiation were established for the notch geometries and thermal cycling conditions used in this program. Test results indicate that the resistance to DHC initiation is dependent on notch root radius, which is shown by optical metallography and scanning electron microscopy to have a significant effect on the distribution and morphology of the notch-tip reoriented hydrides. In addition, it is observed that one tube is less resistant to DHC initiation than the other tube, which may be attributed to the differences in their microstructure and texture. There is a reasonable agreement between the test results and the predictions from the EPZ model.

scholarly journals Detection of Mechanical Abnormalities in Induction Motors by Electric Measurements

1999 ◽  
Vol 5 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Andrzej M. Trzynadlowski
Keyword(s):  
Induction Motors ◽  
Input Power ◽  
Motor Drives ◽  
Operating Conditions ◽  
Induction Motor Drives ◽  
Non Invasive ◽  
Stator Current ◽  
Rotor Imbalance ◽  
Rotor Cage ◽  
Invasive Diagnostics

The paper gives an overview of the issues and means of detection of mechanical abnormalities in induction motors by electric measurements. If undetected and untreated, the worn or damaged bearings, rotor imbalance and eccentricity, broken bars of the rotor cage, and torsional and lateral vibration lead to roughly a half of all failures of induction motor drives. The detection of abnormalities is based on the fact that they cause periodic disturbance of motor variables, such as the speed, torque, current, and magnetic flux. Thus, spectral analysis of those or related quantities may yield a warning about an incipient failure of the drive system. Although the traditional non-invasive diagnostics has mostly been based on the signature analysis of the stator current, other media can also be employed. In particular, the partial instantaneous input power is shown, theoretically and experimentally, to offer distinct advantages under noisy operating conditions. Use of torque and flux estimates is also discussed.

Paper 13: Cavitation and Viscosity between Plain Annular Thrust Surfaces

1967 ◽  
Vol 182 (14) ◽  
pp. 107-111
Author(s):  
B. S. Nau
Keyword(s):  
Shear Rate ◽  
Effective Viscosity ◽  
Thrust Bearing ◽  
Threshold Value ◽  
Mineral Oil ◽  
Operating Conditions ◽  
Shear Stresses ◽  
Face Seal ◽  
Lubricating Film ◽  
The Mean

The configuration investigated corresponds to that of a face-seal or ungrooved parallel-face thrust bearing. Film thicknesses and temperatures, and shear stresses were measured for various operating conditions with mineral oil supplied at low pressure to the inner edges of the annuli. Analysis of the experimental results confirms the importance of the bearing parameter, 6ηω02/ h02, in determining the load carried hydrodynamically. At a given temperature the mean effective viscosity of the lubricating film depends on the shear rate, for values in the range 106–107 s–1, decreasing linearly above a threshold value. The cause of this phenomenon is believed to be cavitation occurring in the film.

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