Economic design of sleeve rotor induction motor using rotor ends

<span>In this paper, the field analysis of the sleeve rotor induction motor (IM) is carried out taking the rotor ends into consideration. Here, the field system equations are derived using the cylindrical model with applying Maxwell's field equations. It is expected that, both starting and maximum torques will increase with taking the rotor ends than that without rotor ends. A simple model is used to establish the geometry of the rotor ends current density and to investigate the air gap flux density. The magnetic flux is assumed to remain radially constant through the very small air gap length between the sleeve and stator surfaces. Variation of the field in the radial direction is ignored and the skin effect in the axial direction is considered. The axial distributions of the air gap flux density, the sleeve current density components and the force density have been determined. The motor performance is carried out taking into account the effects of the rotor ends on the starting and normal operations. The sleeve rotor resistance and leakage reactance have been obtained in terms of the cylindrical geometry of the machine. These equivalent circuit parameters have been calculated and plotted as functions of the motor speed with and without the rotor ends.</span>

Electromechanical Coupling Characteristics Analysis and Research of Rotation-Parallel Flexible Robot Manipulator

RP(Rotation-Parallel) flexible robot as a typical electromechanical system. The complex electromechanical coupling effect in the system has a significant impact on the dynamic characteristics and stability of the flexible manipulator. This article investigates the electromechanical coupling dynamics and vibration response characteristics of flexible robot manipulator driven by AC(Alternating Current) servo motor with considering the start-up dynamic characteristics of the motor. Firstly, the physical model including the coupling of electromagnetic and mechanical system is established, and the dynamic model of the whole system is derived based on the global electromechanical coupling effect and Lagrange-Maxwell equations. Secondly, the virtual simulation platform is constructed with the help of MATLAB/Simulink, and the output speed characteristics of the motor drive end and the motion of the moving base are analyzed. Finally, through the joint simulation of MATLAB/Simulink dynamic simulation model and ADAMS/Controls virtual prototype model, the vibration characteristics of flexible manipulator under electromechanical coupling are obtained. The result demonstrates that the electromechanical coupling effect at the motor driving end has an obvious influence on the dynamic characteristics of the flexible manipulator, which is manifested in the increase of the vibration displacement amplitude of the flexible manipulator. With the increase of motor speed, the change of elastic vibration of flexible manipulator becomes larger, which shows that the electromechanical coupling effect of motor driving end has a greater impact on the dynamic characteristics of flexible manipulator at high speed. The analysis results are of great significance to improve the dynamic performance of motor-driven flexible robot manipulator.

If You Are Old, Videos Look Slow. The Paradoxical Effect of Age-Related Motor Decline on the Kinematic Interpretation of Visual Scenes

Perception and action are tightly coupled. However, there is still little recognition of how individual motor constraints impact perception in everyday life. Here we asked whether and how the motor slowing that accompanies aging influences the sense of visual speed. Ninety-four participants aged between 18 and 90 judged the natural speed of video clips reproducing real human or physical motion (SoS, Sense-of-Speed adjustment task). They also performed a finger tapping task and a visual search task, which estimated their motor speed and visuospatial attention speed, respectively. Remarkably, aged people judged videos to be too slow (speed underestimation), as compared to younger people: the Point of Subjective Equality (PSE), which estimated the speed bias in the SoS task, was +4% in young adults (&lt;40), +12% in old adults (40–70) and +16% in elders. On average, PSE increased with age at a rate of 0.2% per year, with perceptual precision, adjustment rate, and completion time progressively worsening. Crucially, low motor speed, but not low attentional speed, turned out to be the key predictor of video speed underestimation. These findings suggest the existence of a counterintuitive compensatory coupling between action and perception in judging dynamic scenes, an effect that becomes particularly germane during aging.

Development of a Robust Scalar Control System for an Induction Squirrel-cage Motor Based on a Linearized Vector Model

The paper considers the problem of developing a digital system for an induction motor speed control which has a sensor and a speed regulator to increase accuracy of speed control. Speed control is carried out by a scalar method due to consistent change in the stator frequency and voltage. To obtain the uniformity of the motor overload capability in a given range the control mode is used associated with maintaining uniformity of flux linkage of the motor stator. Induction motor scalar models do not possess high accuracy and their parameters and their parameters can vary over a wide range, which complicates the controller design and achievement of robustness of the speed control system. To eliminate these disadvantages, it is proposed to use a vector model in a rotating coordinate system having subjected it to linearization at different points of the operating mode with the account of the adopted law of frequency control, to ensure robust absolute stability of the system on the basis of application of a graphical method for constructing a modified amplitude-phase characteristic.

Stability Analysis of Mechanical Sludge Dewatering Machine Frame Based on Numerical Simulation

Sludge is the inevitable product of sewage treatment plant and sewage treatment. Before sludge treatment, dewatering is generally required. Mechanical sludge dewatering machine is a common sludge dewatering equipment. Due to the complex operation conditions, the stability of sludge dewatering machine frame directly affects its reliability. In this paper, a mechanical sludge dewatering machine frame as the research object, based on ANSYS Workbench finite element analysis platform, static analysis and modal analysis. The analysis results show that: under normal working conditions, the maximum variable of the frame is 0.07mm, which can effectively ensure the normal operation of the sludge dewatering machine; the equivalent stress is 4.22Mpa, which is far less than the Xu Yong stress of the material; the vibration of the first two modes of the frame is relatively concentrated, and the corresponding motor speed under the interference frequency is 1241.4-1595.4r/min, which should be avoided in the use process.

Design and Experimental Research of Variable Formula Fertilization Control System Based on Prescription Diagram

In order to solve the problems such as the inability to automatically mix a variety of solid fertilizers and the unreasonable fertilizer amount, improve fertilizer utilization, and reduce production costs, this study designs a variable formula fertilization control system based on a prescription diagram, including pressure sensor, speed sensor, servo motor, fertilizer discharge actuator, Programmable Logic Controller (PLC controller), vehicle control terminal, etc. Based on pre-loaded soil prescription diagram and combining fertilizer pressure and ground wheel speed detection information, the system obtained a formula fertilization control strategy through calculation to realize the function of fast and automatic formula of nitrogen, phosphorus, and potassium fertilizers and precise variable fertilization. The experimental study on the performance of the variable formula fertilization control system showed the following: the measurement error range of the pressure sensor was 0.005~0.03%; the relationship between the motor speed and the amount of nitrogen, phosphorus, and potassium fertilizer discharged was calibrated. Three gears were established for the motor speed: low (10 r/min), medium (30 r/min), and high (50 r/min); the measurement accuracy of the speed sensor was above 98%. The test verified that the control accuracy of the variable formula fertilization system reached more than 95%, which met the requirements of fast automatic formula and precise variable fertilization and had good practicability and economy.

Three-Phase Induction Motor Speed Estimation Using Recurrent Neural Network Structure

In induction motor speed control method, the development of the field-oriented control (FOC) algorithm which can control torque and flux separately enables the motor to replace many roles of DC motors. Induction motor speed control can be done by using a close loop system which requires a speed sensor. Referring to the speed sensor weaknesses such as less accurate of the measurement, this is due to the placement of the sensor system that is too far from the control system. Therefore, a speed sensorless method was developed which has various advantages. In this study, the speed sensorless method using an artificial neural network with recurrent neural network (RNN) as speed observer on three-phase induction motor has been discussed. The RNN can maintain steady-state conditions against a well-defined set point speed, so that the observer is able and will be suitable if applied as input control for the motor drives. In this work, the RNN has successfully estimated the rotor flux of the induction motor in MATLAB R2019a simulation as about 0.0004Wb. As based on speed estimation error, the estimator used has produced at about 26.77%, 8.7% and 6.1% for 150rad/s, 200rad/s and 250rad/s respectively. The future work can be developed and improved by creating a prototype system of the induction motor to get more accurate results in real-time of the proposed RNN observer.

Defining the Main Parameters and Performances of the Elevator Motor

Contemporary tendencies relentlessly dictate the conditions for the appearance of a more qualitative, reliable and comfortable elevator chain for the rolling stock of a vertical motion. At the same time, the issues of energy saving and cost-effective use of resources gain currency against the background of rising prices for energy carriers and market prices for various elements that play an essential role in the availability of many electromechanical systems. Unfortunately, attention was paid to the availability of above problems in the elevator sector when the majority of the elevators (about 60% of them) outlived their technical service life that ensured the reliable operation. As a matter of fact, an amazingly important issue is relating to the embedment of reliable, durable and economically substantiated components of electromechanical systems into contemporary Ukrainian elevators. The purpose of the research done was to define the main parameters and performances of the asynchronous elevator motor of an ADB180M6 type. The motor is powered from the industrial network of 50 Hz and the frequency converter with the frequency of 50Hz and 16.6 Hz. This scientific paper uses the methods of physical investigations. The elevator motor test data satisfy the reliability parameters that make any elevator user feel comfortable. The main measurement data obtained for the engine No43886 of an ADB180M6 type powered from the frequency converter “Altivar” of 22kW with the motor speed of 910 rpm and 289 rpm satisfy the requirements of the regulatory documentation. The noise level is within satisfactory margins.

The "disease of the crazy hatman" and the effects of human exposure to mercury: A case report / A "doença do homem do chapéu maluco" e os efeitos da exposição humana ao mercúrio: Um relato de caso

INTRODUCTION: Mercury, in addition to being a heavy metal, is considered a neurotoxin, that is, a substance capable of negatively affecting the neurological functions of the human body. Nowadays, ““Mad Hatter's Disease”” is the name used to characterize these neurological disorders caused by mercury. PURPOSE: to report a clinical case of the manifestation of “Mad Hatter's Disease”, as well as to discuss about the effects of human exposure to mercury. METHODOLOGY: this is a clinical case report, in which the patient is essential. CASE REPORT: A 45-year-old male patient, gold miner, from a riverside community in the Amazon, was referred to the hospital with complaints of headache, extremities tremor, diarrhea, tiredness, discouragement, irritability, depression, unusual shyness and hallucinations. On physical examination, the patient was anxious, irritable, symmetrical small-amplitude tremors in the extremities, hyperreflexia ++/4+ in the upper limbs, +/4+ in the lower limbs, normal muscle strength, mild ataxia of the right hand, stained skin and mucous membranes, and acyanotic, with erythematous-scaly lesions, confluent on the trunk, palms and soles of the feet. Screening for mercury poisoning was performed, where it was found, both in blood and urine, the presence of mercury 20 times above the biological tolerance limit. A battery of specific neuropsychological tests was carried out in neurotoxicological assessments and these demonstrated impairment of the cognitive domains (deficit of memory, attention, concentration, reasoning and abstraction) and alterations in motor functions, showing reduced coordination and motor speed. The diagnosis of hydrargyrism or occupational chronic metallic mercuralism (MMCO) was given. DISCUSSION: Chronic occupational exposure to inorganic mercury can cause subclinical abnormalities, as well as long-term psychomotor and neuromuscular behavioral impairment. Neuropsychiatric abnormalities (inattention, memory, interpretation, and motor performance) appear to be dose-related. FINAL CONSIDERATIONS: chronic exposure to metallic mercury vapor characteristically compromises the nervous system, initially with nonspecific symptoms and, later, with characteristic motor disorders - small amplitude tremor, paresis, dysreflexia and difficulty in motor coordination, which gives rise to the "Disease of the Mad Hatter”, and inhaling large amounts of mercury vapor can be lethal.

The Effect of Test Setting Upon Test-Retest Reliability of ImPACT Baseline Tests in High School Athletes

ObjectiveTo determine the test-retest reliability of ImPACT baseline tests across different schools within the same larger concussion management program.BackgroundImPACT is the most widely used concussion management cognitive testing tool. Baseline testing is often required for high school sports participation. Typically, testing occurs every 2 years based on test-retest reliability statistics in previous studies. Demographic and environmental factors, such as age, sex, number of participants, and supervision, all impact baseline performance. Studies to date have not examined test-retest differences across testing sites, such as between school differences.Design/MethodsCross-sectional retrospective design. Valid baseline tests from high school athletes over a 2-year interval were included. Participants who experienced concussions prior to or between tests were excluded. A total of 979 student athletes from 5 schools were included. The Intra-class correlations were determined over a 2-year period for each ImPACT composite score and school.ResultsICC estimates averaged between schools reflected good reliability for visual-motor speed (0.833), visual memory (0.673) and reaction time (0.615) over the two-year period. Verbal memory (0.586) and impulse control (0.556) were less reliable. Between schools a greater range of composite reliability was observed for reaction time (0.484–0.730) and impulse control (0.461–0.655) compared to verbal memory (0.534–0.637), visual memory (0.61–0.719), and visual-motor speed (0.769–914).ConclusionsAs previously established, reliability of ImPACT baselines vary by composite. This study revealed that reliability also varies by setting, as different schools yielded different ICCs. Consistent with the literature, the most reliable measure was visual-motor speed. The greatest difference in reliability between schools was for reaction time. These results suggest that test setting and environment affect reliability of ImPACT baseline scores, with varying effects per composite. Attention must be paid to environmental setting to improve reliability of baseline cognitive test performance to maximize athlete safety.