Advanced Analysis of Motor Currents for the Diagnosis of the Rotor Condition in Electric Motors Operating in Mining Facilities

© 1972-2012 IEEE. Predictive maintenance of electric motors is a topic of increasing importance in many industrial applications. The mining industry is not an exception; many electric motors operating in mining facilities are critical machines, and their unexpected failures may imply significant losses and can be hazardous for the users. Due to these facts, an increasing research effort has been dedicated to investigate new techniques that are able to provide a reliable diagnostic of the motor condition. Over recent years, monitoring of electrical quantities (e.g., motor currents) has emerged as a very attractive option for determining the health of several motor parts (rotor, eccentricities, bearings) due to its very interesting advantages: possibility of remote motor monitoring, noninvasive nature, simple application, broad fault coverage, etc. The traditional methods based on the analysis of motor currents during a steady-state operation [motor current signature analysis (MCSA)] are being complemented when not replaced by more reliable approaches. This paper applies an innovative transient-based methodology to several case studies referred to large motors operating in mining facilities. The results prove how this modern methodology enables us to overcome some important drawbacks of the classical MCSA, such as its unsuitability under varying speed conditions, and may provide an earlier indication of rotor electrical asymmetries under such working conditions

Evaluation of the Detectability of Electromechanical Faults in Induction Motors Via Transient Analysis of the Stray Flux

© 1972-2012 IEEE. The stray flux that is present in the vicinity of an induction motor is a very interesting information source to detect several types of failures in these machines. The analysis of this quantity can be employed, in some cases, as a supportive tool to complement the diagnosis provided by other quantities. In other cases, when no other motor quantities are available, stray flux analysis can become one of the few alternatives to evaluate the motor condition. Its noninvasive nature, low cost, and easy implementation makes it a very interesting option that requires further investigation. The aim of this work is to evaluate the suitability of the stray flux analysis under the starting transient as a way to detect certain faults in induction motors (broken rotor bars and misalignments), even when these types of faults coexist in the motor. To this end, advanced signal processing tools will be applied. Several positions of the flux sensors are considered in this study. Also, for the first time, a fault indicator based on the stray flux analysis under the starting is introduced and its sensitivity is compared versus other indicators relying on other quantities. It must be emphasized that, since the capture of the transient and steady-state flux signals can be carried out in the same measurement, the application of the approach presented in this work is straightforward and its derived information may become crucial for the diagnosis of some faults.Ministerio de Economía y Competitividad’ (MINECO) and FEDER program in the framework of the ‘Proyectos I+D del Subprograma de Generación de Conocimiento, Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia’ (ref: DPI2014-52842-P)

Evaluation of the Damper Condition in Synchronous Motors through the Analysis of the Transient Stray Fluxes and Currents considering the Effect of the Remanent Magnetism

(c) 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] This paper proposes the qualitative and quantitative analysis of stray-flux and current data under starting to detect damper faults in cylindrical rotor synchronous machines. These machines are typically employed in high power applications and their possible outages may imply huge costs for the industries or plants where they operate. The damper cage is a critical part of these machines and a potential source of catastrophic failures. However, few research works have provided feasible alternatives to monitor the condition of such element. This work analyses the viability of analyzing the electromotive force signals induced by the stray-flux in external coil sensors as well as current signals under starting to diagnose damper faults. The results obtained with laboratory machines with different levels of damper damage show that the analyses of those signals can provide very useful information for determining how the damper degrades over time. Moreover, the paper studies the effect of the remanent magnetism over the viability of the approaches and provides solutions to overcome this problem. The conclusions are valuable for field engineers since, nowadays, there are few available solutions that allow monitoring the condition of such element without motor disassembly.This work was supported in part by the Spanish "Ministerio de Ciencia Innovacion y Universidades" and in part by the FEDER program in the framework of the "Proyectos de I+D de Generacion de Conocimiento del Programa Estatal de Generacion de Conocimiento y Fortalecimiento Cientifico y Tecnologico del Sistema de I+D+i, Subprograma Estatal de Generacion de Conocimiento" (ref: PGC2018-095747-B-I00).Castro-Coronado, H.; Antonino-Daviu, JA.; Quijano-Lopez, A.; Llovera Segovia, P.; Fuster Roig, VL.; Serrano Iribarnegaray, L.; Dunai, L. (2021). Evaluation of the Damper Condition in Synchronous Motors through the Analysis of the Transient Stray Fluxes and Currents considering the Effect of the Remanent Magnetism. IEEE Transactions on Industry Applications. 57(5):4665-4674. https://doi.org/10.1109/TIA.2021.30894574665467457

Pigmentation and production of vitamins in mango (Mangifera indica L.)

Mango (Mangifera indica L.) is the fifth most cultivated vegetable in the world. One way to classify the mango is according to the color of the peel, they are classified as green, yellow and red. Color is a visual attribute that defines consumer preference in some countries. This diversity of pigmentation is defined by families of genes that code for the production of proteins, which lead to biosynthetic pathways responsible for the production of vitamins and their precursors. In Mexico there is a wide range of colors in the native mango germplasm, which could represent an important source of antioxidants, pigments and would bring benefits for the human health of Mexicans, through the consumption of fresh fruit, or commercial / industrial exploitation of these. According to the literature, this diversity of colors represents a genetic wealth that could be exploited in the genetic improvement programs of the species in the country, to generate new varieties with desirable characteristics in the national and international market. In order to gather and discuss information that contributes to understanding the biochemical and genetic processes that determine said pigmentation and the production of vitamins in mango, this review makes a description of the main genes involved and the biosynthetic pathways of the most common pigments, considering the impact on human health when consuming them, and highlighting the challenges and opportunities that could arise from the use of pigments from Mexican germplasm.Mango (Mangifera indica L.) is the fifth most cultivated plant in the world. One way to classify mango is according to the color of the skin; mangoes are classified as green,  yellow and red. Color is a visual attribute that defines consumer preference in some countries. This pigmentation diversity is defined by families of genes that encode for protein production, which lead to biosynthetic pathways responsible for the production of vitamins and vitamin precursors. In Mexico there is a wide range of colors in the native mango germplasm, which could represent an important source of antioxidants, pigments and would bring benefits to the human health of Mexicans, through the consumption of the fresh fruits, or the commercial/industrial exploitationof these. According to the literature, this diversity of colors represents a genetic richness that could be exploited in the genetic breeding programs of the species in the country, to generate new varieties with desirable characteristics in the national and international market. In order to gather and discuss information that contributes to the understanding of the biochemical and genetic processes that determine such pigmentation and the production of vitamins in mango, this review describes the main genes involved and the biosynthetic pathways of the most common pigments, considering the impact on human health when they are consumed, and highlighting the challenges and opportunities that could be derived from the utilization of pigmentsfrom the Mexican germplasm

Automatic diagnosis of electromechanical faults in induction motors based on the transient analysis of the stray flux via MUSIC methods

(c) 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] In the induction motor predictive maintenance area, there is a continuous search for new techniques and methods that can provide additional information for a more reliable determination of the motor condition. In this context, the analysis of the stray flux has drawn the interest of many researchers. The simplicity, low cost and potential of this technique makes it attractive for complementing the diagnosis provided by other well-established methods. More specifically, the study of this quantity under the starting has been recently proposed as a valuable tool for the diagnosis of certain electromechanical faults. Despite this fact, the research in this approach is still incipient and the employed signal processing tools must be still optimized for a better visualization of the fault components. Moreover, the development of advanced algorithms that enable the automatic identification of the resulting transient patterns is another crucial target within this area. This article presents an advanced algorithm based on the combined application of MUSIC and neural networks that enables the automatic identification of the time-frequency patterns created by the stray flux fault components under starting as well as the subsequent determination of the fault severity level. Two faults are considered in the work: rotor problems and misalignments. Also, different positions of the external coil sensor are studied. The results prove the potential of the intelligent algorithm for the reliable diagnosis of electromechanical faults.This work was supported in part by the Spanish "Ministerio de Ciencia Innovacion y Universidades" and in part by FEDER program in the "Proyectos de I+D de Generacion de Conocimiento del Programa Estatal de Generacion de Conocimiento y Fortalecimiento Cientifico y Tecnologico del Sistema de I+D+i, Subprograma Estatal de Generacion de Conocimiento" (PGC2018-095747-B-I00).Zamudio-Ramírez, I.; Ramirez-Núñez, JA.; Antonino Daviu, JA.; Osornio-Rios, RA.; Quijano-Lopez, A.; Razik, H.; Romero-Troncoso, RDJ. (2020). Automatic diagnosis of electromechanical faults in induction motors based on the transient analysis of the stray flux via MUSIC methods. IEEE Transactions on Industry Applications. 56(4):3604-3613. https://doi.org/10.1109/TIA.2020.2988002S3604361356

Resolving the Inner Parsec of the Blazar J1924-2914 with the Event Horizon Telescope

The blazar J1924-2914 is a primary Event Horizon Telescope (EHT) calibrator for the Galactic center's black hole Sagittarius A*. Here we present the first total and linearly polarized intensity images of this source obtained with the unprecedented 20 mu as resolution of the EHT. J1924-2914 is a very compact flat-spectrum radio source with strong optical variability and polarization. In April 2017 the source was observed quasi-simultaneously with the EHT (April 5-11), the Global Millimeter VLBI Array (April 3), and the Very Long Baseline Array (April 28), giving a novel view of the source at four observing frequencies, 230, 86, 8.7, and 2.3 GHz. These observations probe jet properties from the subparsec to 100 pc scales. We combine the multifrequency images of J1924-2914 to study the source morphology. We find that the jet exhibits a characteristic bending, with a gradual clockwise rotation of the jet projected position angle of about 90 degrees between 2.3 and 230 GHz. Linearly polarized intensity images of J1924-2914 with the extremely fine resolution of the EHT provide evidence for ordered toroidal magnetic fields in the blazar compact core

Patterns of soil organic carbon and nitrogen in relation to soil movement under different land uses in mountain fields (South Central Pyrenees)

Cultivation on mountain landscapes has been identified as a main factor triggering soil erosion. Patterns of erosion, transport and deposition of soil particles in agricultural landscapes appears to be closely linked to that of soil nutrients. In this work the redistribution of soil organic carbon and nitrogen and of soil particles is analysed in different geomorphic parts of mountain fields. A southern orientated hillslope was selected as representative of main land uses in mountain farmland of the Central Spanish Pyrenees. In the region, as much as 74% of its surface was abandoned in the last decades and as a result patterns of soil and nutrient losses in the fields were affected by both land abandonment and tillage. A set of cultivated and abandoned fields with different ages of land abandonment, slope gradients and lengths were selected to conduct this study. In each of the fields, total soil depth sampling was done in different parts of the slope to assess the pattern distribution of soil organic carbon (SOC) and nitrogen (SON). Other general soil properties analysed: pH, EC, carbonate content, grain size distribution and additional information derived from fallout caesium 137 provided supplementary information for better understanding the patterns of soil and nutrient redistribution. In the cultivated fields SOC and SON contents were higher and comparable to contents in the older abandoned fields, because the recovery of the natural vegetation after a long-term period of abandonment equalized the nutrient conditions in the cultivated fields that had regular additions of manure. In general SOC and SON percentages increased from the upper slope to the bottom slope of the fields with percentage increases ranging from 4 to 54% and from 1.5% to as much as 77%, respectively. Similarly, significant increases of SOC and SON inventories (45 and 49%, respectively) were registered at the bottom slopes of longer fields by comparison with lower increases (33 and 30%, respectively) in shorter and steeper fields. Soil deposition at the bottom slope as indicated by the 137Cs residuals was paralleled with increases in SOC and SON contents. Under the land use practices in the studied fields the bottom slope positions accumulate soil particles and act as sinks of soil carbon and nitrogen in these mountain agricultural landscapes.status: publishe

Wireless Electroencephalogram Acquisition System for Recordings in Small Animal Models

This work presents the implementation of a small, light and wireless electroencephalogram (EEG) and intracranial EEG (iEEG) acquisition system called "Wireless Neuro Boards" (WIRNEBOs), intended for electrophysiological recordings in small animal models. The system consists of two devices: a battery powered transmitter, in charge of the acquisition and transmission tasks, whose dimensions and weight are 58 mm by 38 mm by 10 mm and 25 g respectively, and a receiver which is connected to a host computer to store and process the acquired signals. The main characteristics of the WIRNEBOs include the use of 24 bits, 8 channels medical Analog Front End (AFE). The system was tested with a sample rate of 500 samples per second (SPS) and has power autonomy up to 8 hours and presents an electric noise of less than 1μV. The wireless radiofrequency (RF) link did not present any corruption or data loss in a range up to 5 meters. Modular design is novel; allowing the implementation of new versions with higher number of channels and improvements in sample rate, autonomy, range of the communications, among others