Effects of brush shift on DC motor performance

This thesis focuses on the effects of brush shifting on the performance of brushed DC motors. It begins by explaining the basic operating principles of electric machines and compares them to one another. The thesis then shows the implementation of a simulation model on Ansys Maxwell in order to validate the theory presented regarding armature reaction and demonstrates the possibilities of predicting motor characteristics via simulation. Finally the thesis presents measurements and results performed on an experimental setup to prove and validate the claim of improving motor performance using brush shifting.ObhájenoThis thesis focuses on the effects of brush shifting on the performance of brushed DC motors. It begins by explaining the basic operating principles of electric machines and compares them to one another. The thesis then shows the implementation of a simulation model on Ansys Maxwell in order to validate the theory presented regarding armature reaction and demonstrates the possibilities of predicting motor characteristics via simulation. Finally the thesis presents measurements and results performed on an experimental setup to prove and validate the claim of improving motor performance using brush shifting

Effects of brush shift on DC motor performance

This thesis focuses on the effects of brush shifting on the performance of brushed DC motors. It begins by explaining the basic operating principles of electric machines and compares them to one another. The thesis then shows the implementation of a simulation model on Ansys Maxwell in order to validate the theory presented regarding armature reaction and demonstrates the possibilities of predicting motor characteristics via simulation. Finally the thesis presents measurements and results performed on an experimental setup to prove and validate the claim of improving motor performance using brush shifting.ObhájenoThis thesis focuses on the effects of brush shifting on the performance of brushed DC motors. It begins by explaining the basic operating principles of electric machines and compares them to one another. The thesis then shows the implementation of a simulation model on Ansys Maxwell in order to validate the theory presented regarding armature reaction and demonstrates the possibilities of predicting motor characteristics via simulation. Finally the thesis presents measurements and results performed on an experimental setup to prove and validate the claim of improving motor performance using brush shifting

Electrical Machine Topologies: Hottest Topics in the Electrical Machine Research Community

In this article, the state of the art in electrical machine design is outlined underlining the problems and challenges to be solved by engineers. As highlighted in this article, even if electrical machine design is often considered a mature issue from the technical and technological point of view, every year, new progresses and steps forward are made. New and more sophisticated design tools can be used worldwide, and innovative manufacturing processes, new insulation materials, and higher performance magnetic materials are available on the market. In addition, the evolution of the hardware used in digital control and new powerful power electronic devices represents a constant stimulus to improve the performance of electrical machines and reintroduce electrical machine structures that were not adopted in the past due to technological and technical constraints. As shown in this article, electrical machine design is an evergreen topic, and its importance is rising more each year under the push of more energy-saving requirements and higher-efficiency systems for electromechanical conversion. A green world will not be possible without electrical machines

Utilization of bottom ash for alkali-activated (SI-AL) materials: a review

In Malaysia, 180 tons/day of solid waste bottom ash are produced by a Tanjung Bin power station, which is one of the four coal power plants in Malaysia. Hence, to overcome this problem, the solid waste could be used as source material in construction industry using geopolymer technique. Alkali-activated materials are introduced as an alternative materials to ordinary Portland cement (OPC) in the construction industry. There are many types of alkaline activator raw materi als such as bottom ash, fly ash, metakaolin and so on that can be substituted the materials existing such as cement and fine or course aggregate in the market now to make any production where the materials are coming from waste.The geopolymerization process involves a substantially fast chemical reaction under alkaline conditions with Si and Al minerals that results in a three‐dimensional polymeric chain and ring structure consisting of Si‐O‐Al‐O. The higher Si‐O‐Al‐O bonds are contained in the geopolymer, the higher compressive strength results will find. Several types of building materials such as

Numerical modelling of sinusoidal brushless motor for aerospace actuator systems

The interest in electromechanical actuators (EMA) has been growing because of the development of next generation aircraft, based on the More Electric design. Electromechanical actuators have been gaining increased acceptance as they are becoming more and more safety-critical actuation devices: for prognostics and health management purposes of EMA, reliable and representative simulation models are needed in order to identify failures. This paper presents a multi domain model of EMA and it focuses on the numerical modelling of the Permanent Magnet Synchronous Motor (PMSM), also kwon as Sinusoidal Brushless Motor. The choice of the multi domain simulation is necessary to improve the simplifying hypotheses that are typically considered in numerical models and that are mostly used for prognostic analyses of electromechanical actuators

Contributions to the commutation analysis of uncompensated single phase universal motors

In this thesis various aspects of the electromagnetic effects influencing the commutation of uncompensated single phase universal motors are investigated. An introduction to the subject as well as a review of significant literature on the subject are given. The literature review includes classical text books about commutator motors as well as more recent publications about the mathematical analysis of the commutation of universal motors. Subsequently, the analysis of the most important inductances of the machine is outlined that comprises the analytical and numerical calculation as well as the measurement of the machine inductances using different measurement techniques. Moreover, a brush model for commutation analysis of small commutator motors is presented. Equivalent circuits of the brush are established for the cases of one coil shorted and two coils shorted by one brush, and a strategy to obtain their elements is proposed. This uses a dedicated finite difference program to calculate the effective brush resistance between all pairs of terminals. The treatment of the boundary conditions is critical in this process. The resulting terminal resistances are regarded as combinations of a set of internal resistances and this nonlinear relationship is inverted to obtain the internal resistors using a modified Newton-Raphson method. Results are presented showing the influence of anisotropy and geometry, and a simplified example of commutation analysis using the model established is given. In the next step the arcing phenomenon in analysed mathematically. Equations are given for the pre-arcing phase, the arcing phase and the post-arc oscillation. Equivalent circuits for the different phases are proposed and the equations are derived strictly from a circuit point of view. In the analysis a constant arc voltage (confirmed by experimental data and literature on the subject) and a minimum uncommutated residual current necessary for arc ignition are assumed. Those quantities are adopted from reviewed literature and used in the calculations. The design of a motor test bench is described that allows to measure the motor performance according to the principle of the reaction dynamometer. The load machine is mounted on air bearings to minimize possible torque errors in the measurements. A measured torque speed characteristic of a universal motor is shown as well as the torque as a function of the motor current. These measurements were carried out at reduced motor voltage to keep the shaft speed within reasonable limits. Furthermore, theoretical and experimental investigations are carried out in order to estimate how strongly certain rotor coils undergoing rapid current changes affect each other due to mutual coupling and how the mutual coupling changes in the presence of a damping field winding. Several FEA simulations are performed in order to get an insight into the flux pattern if rotor coils are acting on each other and the field winding is allowed to impose its damping effect on the rotor coils. Simple AC measurements are performed as well as di/dt - tests using a more complex oscillating circuit for measurements of the change of the di/dt of a rotor coil with and without the presence of an active field winding. Additionally, investigations are carried out in order to analyse the influence of power cord and source impedances on the ability of the field winding of an uncompensated universal motor to damp flux variations caused by the commutation process. The motor is regarded as a harmonic generator with the power cord and the source impedance acting as a load. Rotational tests are carried out with different loads connected to the field winding and the Fourier spectrums of the field voltage are evaluated. In the final stage a simulation model is described that uses deductions from the previous chapters and that simulates the electromagnetic behaviour of the machine including the complex problem of brush commutation. Measured and calculated signals suitable for validation of the model were compared in order to evaluate the accuracy of the model with regard to motor performance and commutation analysis

Performance of disc brushless DC motor applied as gearless drive for wheelchair

The currently used electric drive for a wheelchair consists of brush permanent magnet DC motor and mechanical transmission that drives the wheels. The overall efficiency of this kind of drive usually does not exceed 60%. At present there is under study much more effective drive that consists of brushless DC motor which embedded into the wheel rim directly drives the wheelchair. This type of high efficiency gearless drive is the object of this thesis project. The particular brushless DC motor is a torus - type motor with a high energy rare - earth magnets and ferromagnetic teeth that fill in the space between the coils of Gramme\u27s winding. The objectives of the project were to determine by computer simulation and laboratory test the electromechanical characteristics of the motor prototype in steady - state and dynamic conditions. For this purpose the measurement stand has been built and measurements were carried out in variable load conditions. To analyze the motor characteristics theoretically the mathematical models of the motor were developed one for steady - state and one for dynamic operation. The simulation of the motor drive was done using MATLAB/ SIMULINK software package. The results obtained from simulation confirm the requirements put on the gearless wheelchair drive and the determined motor ratings are as follows: supply voltage - 24 V, input current - 8.7 A, torque - 9.7 Nm, speed - 161 rpm, efficiency, 78 %. The cogging torque is practically unnoticeable. The results obtained from the test practically do not differ from those obtained from simulation. It means the calculation model used in simulation of steady - state and dynamic conditions has been verified positively

Modeling And Forced Vibrations For A Universal Electric Motor

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2011Elektrik motorları günümüzde neredeyse her türlü cihaz ve makinalarda vazgeçilmez olarak kullanılan mekanik güç sağlayıcı elemanlardır. Dolayısı ile elektrik motorlarının kalitesi, güvenirliği ve ömrü bu motorları kullanan makinelerin kalitesini doğrudan etkilemektedir. Bu bağlamda elektrik motorlarının titreşim ve gürültü anlamındaki özellikleri ön plana çıkmaktadır. Bu çalışmanın temel amacı, elektrik motoru dinamiğinde etkili olan mekanik ve elektriksel kaynaklı zorlanmış titreşimleri tahmin edebilecek güvenilir bir model ortaya koymaktır. Bu kapsamda motorun herbir parçasının ayrı ayrı sonlu eleman modeli oluşturulmuş ve bunlar deneysel modal analiz ile güncellenmiştir. Daha sonra motor elemanların güncellenmiş bu esnek modelleri MSC ADAMS programında monte edilmiştir. Herbir aşamada yine deneysel modal analiz ile modelin doğruluğu hem kontrol edilmiş hem de gerekli güncellemeler yapılmıştır. Motorun serbest titreşim modeli elde edildikten sonra, motor üzerinde kuvvet üreten etkilerin modelleri elde edilmiştir. Bunlar kabaca mekanik ve elektriksel olarak sistemi uyaran bileşenlerdir. Bu etkilerin modele eklenerek zorlanmış titreşim modeli elde edimiş, incelenmiş ve tasarlanan test düzeneği baz alınarak gerekli düzenleme ve düzeltmeler yapılmıştır.Nowadays, electric motors are the most common machines which are used almost all machine in order to provide mechanical power. So, quality, reliability and life span of electric motors directly influence machines where the electric motors are used. As a result, vibration and acoustic properties of electric motors take over in order to decrease total noise and vibration problems in the machines. The aim of this study is modelling a reliable numerical model of a universal electric motor in order to investigate the effects of the mechanical and electrical forces on the dynamics of the electric motor. In this context, every parts of the electric motor are modelled as a FE model and these models are validated by experimental modal analysis. After this study, all of these models are assembled in the MSC ADAMS. So, free vibration numerical model of the electric motor is created. One step further of free vibration model is to compose a forced vibration model which contains dynamic forces created by both electrical and mechanical manner. A test rig is designed in order to validate this numerical model. Effects of dynamic forces are investigated and forced vibration numerical model is improved on the basis of experimental data.Yüksek LisansM.Sc