Motor Running Research Articles

Detection of Stator Winding Inter-Turn Short Circuit Fault in Induction Motor Using Vibration Signals by MEMS Accelerometer

This paper presents a novel method for detecting stator winding inter-turn short circuit fault in a three-phase induction motor by vibration signature analysis using non-electrical contact type microelectromechanical systems (MEMS) accelerometer. The present work detects inter-turn short circuit by vibration analysis in a three-phase induction motor running under different load conditions. Theoretical analysis of stator winding under inter-turn short circuit condition has been presented. Experimental investigations have been carried out to detect inter-turn short circuit fault by vibration signature analysis using a MEMS accelerometer with three-phase induction motor operating under different conditions. The spectral analysis of motor vibration has been carried out using radix-2 decimation in time fast Fourier transform algorithm. The appearance of particular characteristic frequency components in vibration spectrum indicates stator winding inter-turn short circuit faults. The experimental results are found to closely match with the theoretical values, indicating that MEMS accelerometers can be successfully employed for the detection of stator winding inter-turn short circuit fault in induction motors.

Performance evaluation and experimental analysis of a novel single‐phase brushless PM motor

In order to equip the single‐phase brushless permanent magnet (PM) motor with self‐starting capability without a complex structure, we present a new kind of asymmetric air‐gap topology which can lead to the d‐, q‐axis magnetic circuit asymmetry of the motor. The field‐circuit‐coupling finite element method simulation model of the proposed motor controlled with a constant V/f control is built by using the 2D Maxwell software. The geometric parameters of the motor are also optimized by changing pole arc ratio of the PM (αp) and its eccentricity (e), and the operational characteristic is investigated. Finally, an experimental platform of the prototype and its control system are set up. Performance comparison of the experimental results and simulation results of the proposed motor running in various operating modes is reported. All the results show that the asymmetric air‐gap single‐phase brushless PM motor has potential to be used in the household appliances. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Zintegrowany system wspomagania decyzji do diagnostyki akustycznej w badaniu stanu technicznego silnika spalinowego

Presented are possible applications of acoustic diagnostics in inspecting the technical condition of an internal combustion engine with autoignition on the example of the Fiat drive unit with common rail system. As a result of measuring the sound pressure level for specific faults and comparing the noise generated by the motor running smoothly, the detailed maps of changes in the acoustic spectrum are possible to generate. These results may be helpful in the future diagnostics of internal combustion engines. The results of scientific work in the area of research, design and operation of internal combustion engines, conducted at the Department of Automotive Engineering, in cooperation with the Laboratory of Hydraulic Drives & Vibroacoustics of Machines at the Wroclaw University of Technology are included. It has developed an authoritative method of identifying the type of engine damage using game-tree structures. An integrated decision system for induction machine learning was developed to test and identify acoustic properties.

By Staying Together, Two Genes Keep the Motor Running

In this issue of Structure, Lynch etal. (2017) reveal that the interaction between two key proteins in the bacterial flagellar motor results in a shared structural domain. This unusual arrangement keeps the corresponding genes together through the course of evolution.

A New Entropy Bi-Cepstrum Based-Method for DC Motor Brush Abnormality Recognition

Abnormal arcs in dc motors are often associated with various potential failures or operational defaults. Although they may not directly led to motor breakdown, they can be causes to faults, further damages, and fire hazard. There can be arcs between brushes and rotors when motor running under normal condition, known as normal arcs. However, abnormal arcs, which are difficult to be visually distinguished from normal arcs, occur when there is loosen or contamination of brushes. Therefore, detecting the existence and identifying the type of unusual arcs can be applied as an effective method for brush condition monitoring. This paper presents a detection strategy for abnormality in brush based on the online electromagnetic field (EMF) analysis with advanced feature extraction techniques. The techniques aim at finding the unusual changes in EMF to identify abnormal arc among normal ones. Entropy bi-cepstrum applied as feature extraction method is an inverse spectrum of cumulant. Bi-cepstrum is insensitive to noise, and entropy reflects the complexity of the target signal. In the experiment, three typical types of unusual arcs occurring in brush area are successfully identified, and the result shows the accuracy as high as 91.4%. The new strategy with algorithms can serve as a very useful tool for abnormality recognition of the motor brush.

Research on Permanent Magnet Synchronous Motor Driver System of Horizontal Well Tractor

Nowadays, horizontal well technology is being applied to the development of oilfield production capacity more and more. The horizontal well tractor can effectively solve the problem that the instrument can not get to the target layer by gravity. However, in actual conditions, Brushless DC motor (BLDCM) there is a large torque ripple problem, resulting in motor running is not smooth, vibration and noise is too large, can not meet the demand. Therefore, propose horizontal well tractor PMSM sine wave drive technology. The paper discusses the mathematical model of permanent magnet synchronous motor, analyzes the working principle of space vector pulse width modulation (SVPWM) technology, and establishes a speed and current double closed-loop space vector control system of the permanent magnet synchronous motor by using PSIM simulation software. Simulation results verify the robustness of the control system, and the torque ripple of the motor is small, in line with the working conditions of horizontal well tractor.

A New Strategy for BLDC Sensorless Control System and Its Application in Horizontal Well Tractor

The positionless brushless DC motor has the advantages of simple structure, good speed performance and high efficiency. It has become the best choice for horizontal well tractor. This paper introduces a set of brushless DC motor control system, gives the hardware structure of the system and brushless DC motor without Hall sensor control flow chart and the host computer communication interface protocol which solves the problem of phase lag in the case of high speed motor. Aiming at the problem that the parameters of the motor can not be monitored, the host computer monitoring program based on c# can be designed to monitor the parameters of the motor in real time. The experimental results show that the control system can make the motor run smoothly at different speeds, and can monitor the parameters of the motor in real time, suitable for the horizontal well logging and so on the motor control system requires relatively high industrial environment.

Assessing the damage importance rank in acoustic diagnostics of technical conditions of the internal combustion engine with multi-valued logical decision trees

This paper presents possible applications of acoustic diagnostics in inspecting the technical condition of an internal combustion engine with autoignition on the example of the Fiat drive unit with the common rail system. As a result of measuring the sound pressure level for specific faults and comparing the noise generated by the motor running smoothly, the detailed maps of changes in the acoustic spectrum may be generated. These results may be helpful in future diagnostics of internal combustion engines. In the paper, we present the results from the scientific works in the area of research, design and operation of internal combustion engines, conducted at the Department of Automotive Engineering, in cooperation with the Laboratory of Hydraulic Drives & Vibroacoustics of Machines at the Wroclaw University of Technology. The broader study has so far allowed us to develop an authoritative method of identifying the type of engine damage using gametree structures. The present works assess the possibility of using multi-valued logic trees.

Universal bound on the efficiency of molecular motors

The thermodynamic uncertainty relation provides an inequality relating any mean current, the associated dispersion and the entropy production rate for arbitrary non-equilibrium steady states. Applying it here to a general model of a molecular motor running against an external force or torque, we show that the thermodynamic efficiency of such motors is universally bounded by an expression involving only experimentally accessible quantities. For motors pulling cargo through a viscous fluid, a universal bound for the corresponding Stokes efficiency follows as a variant. A similar result holds if mechanical force is used to synthesize molecules of high chemical potential. Crucially, no knowledge of the detailed underlying mechano-chemical mechanism is required for applying these bounds.

Research into the characteristics of horizontal gaseous jets underwater

The gaseous jet of the solid rocket motor running under water is influenced by both gravity and buoyancy, which will have a significant influence on the flow field structure and thrust of the motor, especially in the initial period when vehicles are launching horizontally. The work in this paper consists of three parts: firstly, to understand the mechanism of the thrust oscillation characteristics and the jet structure of a solid rocket motor running under water, as affected by gravity and buoyancy, a 3-d numerical simulation using the volume of fluid (VOF) model was established. Compared with those results neglecting gravity and buoyancy, conclusions were obtained that the jet structure, considering gravity and buoyancy, are more consistent with the experimental results. Secondly, the principle of momentum was used to analyze the flow field structure and the thrust oscillating characteristics in the initial period of operation. Finally, after analyzing the density gradient along the axis of the motor, results indicated that the length of jets under the influence of gravity and buoyancy varies linearly and the slope of the line is related to the working conditions. Comparing the trajectories under different conditions, a common theme emerged. The laws of thermodynamics are also used to simulate the jets as gas-water-vapor, three-phase, systems. The effect of phase transitions on the structure of jets and the characteristics of their thrust form the key conclusions.

Wear Characteristics of Metallic Counterparts under Elliptical-Locus Ultrasonic Vibration

Wear behavior is influential to improve friction drive and wear lifespan of actuators or motors, which work at an elliptical locus vibration. Sliding wear tests of metallic friction pairs are conducted by a laboratory rig of ultrasonic vibration. Surfaces of the different metallic sliders are characterized using surface roughness, Abbott curves and fractal dimension. Results show that surface roughness is reduced to varying degrees in the metallic sliders due to ultrasonic polishing and/or micro-rolling effect. Variations in the fractal dimensions of contact surfaces are consistent with that of surface roughness. Wear traces demonstrate that plastic deformation and cracking are the primary failure modes. Where the driving tip on the slider is in intermittent contact followed by impact effects, ripples of 3~5 μm traces suggest the occurrence of fretting in duralumin sliders. Nodular cast iron showed a favorable performance during running of ultrasonic motor, exhibiting a stable output performance and durable wear life.

FPGA Based Control Method for Three Phase BLDC Motor

This paper introduces a good method which is helpful to assist in the design and control of cost effective, efficient Brushless Direct Current (BLDC) motors. Speed Control of BLDC motor using PIC microcontrollers requires more hardware, and with the availability of FPGA versatile features motivated to develop a cost effective and reliable control with variable speed range. In this paper, an algorithm which uses the Resolver signals captured from the motor is developed with the help of Resolver to Digital converters. The program has been written using VHDL. This program generates the firing pulses required to drive the MOSFETs of three phase fully controlled bridge converter driven by drivers. Then the program has been loaded on the Spartan- 3 FPGA device and tested on the 30V, 2000 rpm BLDC motor which can make the motor run at constant speed ranging from 10 to 2000 rpm. The proposed hardware and the program are found to be very good and efficient. The results are good compare to PIC Microcontroller based design.

Simulation Model for Prediction of Transient Performance Characteristics of Single–Phase Shaded Pole Motor

Abstract Paper proposes mathematical model of single phase shaded pole motor suitable for analysis of motor dynamic behavior. Derived mathematical model from d–q reference frame theory is applied at motor simulation model. Derived simulation model enables analysis of transient performance characteristics of motor currents, speed and electromagnetic torque under different operating regimes. Obtained results from the simulation are compared with data from analytical calculations based on method of symmetrical components and data from experiment for the purpose of verification of the simulation model. Simulation model is useful for studying the effect of parameters on motor starting and running characteristics at different types of loads.

Acoustic Diagnostics Applications in the Study of Technical Condition of Combustion Engine

AbstractThe paper presents the possible applications of using acoustic diagnostics in inspecting the technical condition of an internal combustion engine with autoignition on the example of the Fiat drive unit with common rail system. As a result of measuring the sound pressure level for specific faults and comparing the noise generated by the motor running smoothly, the detailed maps of changes in the acoustic spectrum are possible to generate. These results may be helpful in the future diagnostics of internal combustion engines. In the paper, the results of scientific work in the area of research, design and operation of internal combustion engines, conducted at the Department of Automotive Engineering, in cooperation with the Laboratory of Hydraulic Drives & Vibroacoustics of Machines at the Wroclaw University of Technology are included.

Numerical simulation and experimental verification of heat transfer from a finned housing of an electric motor

Engineering analyses based on the results of numerical simulation enable shortening the duration and reducing the costs of the development and tests of equipment models or prototypes. As numerical modeling methods have uncertainties, experimental verification is required. In the literature, there are many examples of application of numerical modelling to the thermal processes occurring in electric motors but the experimental methods of model validation are not so well described.In this work, numerical and experimental investigations of heat conduction in the finned housing of an electric motor, and the comparison between their results are presented. 3D geometrical model of the motor rated 7.5kW was imported to COMSOL Multiphysics software package. After defining thermophysical properties of the housing material and heat flows generated in the motor, and setting boundary conditions, a numerical model of heat conduction in the motor housing was obtained. The model allowed to calculate steady-state temperature distribution in the housing cross section. In order to validate the model, investigations of the temperature distribution were carried out using FLIR SC7600 thermovision camera. Steady-state temperature distribution on the surface of housing of the motor run in idling conditions was recorded by thermography. The obtained thermograms were found to be in satisfactory quantitative agreement with the simulated temperature distribution as the real values of temperature differences measured across the housing cross section deviated not more than 10% from the calculated ones. The research confirmed that a thermovision camera is an efficient experimental tool for the validation of numerical models of the heat transfer phenomena in the finned housing of an electric motor.

Study into overcurrent protection technology for mine asynchronous motor

In the running of mine motor, it is extremely vulnerable to overcurrent faults such as short-phase failure or short circuit, so the study in overcurrent protection for asynchronous motor is of great significance. The characteristics of overcurrent failure for mine asynchronous motor are analyzed, a mathematical model of overcurrent fault is established and the overcurrent protection principle is analyzed in this paper. Due to the malfunction defect of traditional symmetrical short-circuit protection in the starting of large motor, a new protection scheme is proposed, which is to adopt the phase-sensitive protection based on power factor detection and short-circuit fault detection scheme based on wavelet transform Mallat algorithm. Meanwhile, a method of asymmetrical fault protection based on negative-sequence current detection is proposed in the paper. In addition, overcurrent protection technology is applied to the overcurrent protection of mine squirrel cage asynchronous motor, of which the effectiveness and the practicality have been verified.

Chemotactic dynamics of catalytic dimer nanomotors.

Synthetic chemically powered nanomotors possessing the ability of chemotaxis are desirable for target cargo delivery and self-assembly. The chemotactic properties of a sphere dimer motor, composed of linked catalytic and inactive monomers, are studied in a gradient field of fuel. Particle-based simulation is carried out by means of hybrid molecular dynamics/multiparticle collision dynamics. The detailed tracking and motion analysis describing the running and tumbling of the sphere dimer motor in the process of chemotaxis are investigated. Physical factors affecting chemotactic velocity are discussed, and quantitative relations are presented. The influence of the geometry of sphere dimer motors on the chemotactic dynamics is explored, which is beneficial for the design of motors with high sensitivity for detecting the surrounding environment.

Experimental Evaluation of Performance of Constant Power Prime-Mover Driven Isolated 3-φ SEIG for Pico-Hydro Power Generation System in Remote Mountainous Region of Himalayas

This paper presents the experimental evaluation of the performance of 3-φ self-excited induction generator (SEIG) suitable for pico-hydro power generation system feeding domestic load in remote mountainous region. The use of induction generators is most suitable for renewable energy conversion systems due to their enormous advantages over conventional synchronous generators. Important features of induction generators include the simplicity in construction, ruggedness, simplified control, ease in maintenance and small size per generated kW. The performance characteristics of 3-φ SEIG feeding isolated load are evaluated using MATLAB-Simulink model based on the prevalent renewable energy sources inputs and loading conditions in mountainous terrain of Himalayas. The results are validated using an experimental set-up comprising of 3-φ, 3 HP induction motor run as 3- φ induction generator driven by 5HP, 4-pole DC shunt motor acting as prime-mover.

Motor and cognitive growth following a Football Training Program.

Motor and cognitive growth in children may be influenced by football practice. Therefore the aim of this study was to assess whether a Football Training Program taken over 6 months would improve motor and cognitive performances in children. Motor skills concerned coordinative skills, running, and explosive legs strength. Cognitive abilities involved visual discrimination times and visual selective attention times. Forty-six children with chronological age of ∼9.10 years, were divided into two groups: Group 1 (n = 24) attended a Football Exercise Program and Group 2 (n = 22) was composed of sedentary children. Their abilities were measured by a battery of tests including motor and cognitive tasks. Football Exercise Program resulted in improved running, coordination, and explosive leg strength performances as well as shorter visual discrimination times in children regularly attending football courses compared with their sedentary peers. On the whole these results support the thesis that the improvement of motor and cognitive abilities is related not only to general physical activity but also to specific ability related to the ball. Football Exercise Programs is assumed to be a “natural and enjoyable tool” to enhance cognitive resources as well as promoting and encouraging the participation in sport activities from early development.

Nocturnal to Diurnal Switches with Spontaneous Suppression of Wheel-Running Behavior in a Subterranean Rodent.

Several rodent species that are diurnal in the field become nocturnal in the lab. It has been suggested that the use of running-wheels in the lab might contribute to this timing switch. This proposition is based on studies that indicate feed-back of vigorous wheel-running on the period and phase of circadian clocks that time daily activity rhythms. Tuco-tucos (Ctenomys aff. knighti) are subterranean rodents that are diurnal in the field but are robustly nocturnal in laboratory, with or without access to running wheels. We assessed their energy metabolism by continuously and simultaneously monitoring rates of oxygen consumption, body temperature, general motor and wheel running activity for several days in the presence and absence of wheels. Surprisingly, some individuals spontaneously suppressed running-wheel activity and switched to diurnality in the respirometry chamber, whereas the remaining animals continued to be nocturnal even after wheel removal. This is the first report of timing switches that occur with spontaneous wheel-running suppression and which are not replicated by removal of the wheel.