Benedito Antonio Luciano

Fillet Weld Identification for Automatic Inspection of Spherical Tanks

In this article the development of a system for fillet weld identification is considered for automatic inspection of storage spheres. Distance sensors based on different physical principles are characterized and selected, thus getting, greater confidence of the acquired data. The data provided from the different types of sensors will be submitted to a fusing process, aiming at to increase the confidence and performance of the system.

Current transformers with nanocrystalline alloy toroidal core: analytical, computational and experimental studies

In this paper are presented theoretical analysis and experimental results concerning the performance of toroidal cores used in current transformers. For most problems concerning transformers design, analytical methods are useful, but numerical methods provide a better understanding of the transformers electromagnetic behaviour. Numerical field solutions may be used to determine the electrical equivalent circuit parameters of toroidal core current transformers. Since the exciting current of current transformers alters the ratio and phase angle of primary and secondary currents, it is made as small as possible though the use of high permeability and low loss magnetic material in the construction of the core. According to experimental results presented in this work, in comparison with others soft magnetic materials, nanocrystalline alloys appear as the best material to be used in toroidal core for current transformers.

Architectural specification for infusion pumps and realization towards safety technological trends

According to the Food and Drug Administration, infusion pumps are considered nowadays the most safety-critical medical device due to the nature of their operations and associated risks. The design of these devices is still an open question and several improvement initiatives are under research. However the released specifications of such systems are not yet adapted to the current state-of-art systems architectural developments. For example, in our regulatory research, we were not able to mention any project meeting the views and viewpoints patterns for specification and documentation of system and software architectures during the engineering process. This paper proposes a functional specification of an architecture for infusion pumps that can be realized through several technological trends for these products in order to improve safety. Therefore, we validate our specification by developing a prototype of an infusion pump that can be programmed through data retrieved from a webservice using a mobile application as a remote control and changing the infusion parameters according to accuracy properties as a multi-channel device. Thus, the main contribution of this paper can be presented as a distributed architecture for this sort of device, allowing early integration with Electronic Health Records and Patient Health Records for embedded systems domain implying in risk reductions during the programming activity.

Performance of single wire earth return transformers with amorphous alloy core in a rural electric energy distribution system

In this paper are presented some considerations about the performance of single wire earth return amorphous alloy core transformers in comparison with conventional silicon steel sheets cores transformers used in rural electric energy distribution network. It has been recognized that amorphous metal core transformers improve electrical power distribution efficiency by reducing transformer core losses. This reduction is due to some electromagnetic properties of the amorphous alloys such as: high magnetic permeability, high resistivity, and low coercivity. Experimental results obtained with some single-phase, 60 Hz, 5 kVA amorphous core transformers installed in a rural area electric distribution system in Northern Brazil have been confirming their superior performance in comparison to identical nominal rated transformers built with conventional silicon steel cores, particularly with regard to the excitation power and to the no-load losses.

Sistema automático para ensaios de perdas em núcleos de transformadores monofásicos

In this paper is presented a low cost automated measurement system developed to obtain the core losses and the excitation current of single-phase transformers. This system includes specifics hardware and software that allows the accomplishment of this aim, as specified by the user. Due to the techniques used in the acquisition and computation of the waveforms involved in loss calculation, the core losses and excitation current are obtained with high accuracy.

Medição de velocidade angular com alta resolução usando enconders de baixa resolução e PLL

In this paper a new approach to perform angular velocity measurement of a motor is presented. The approach is based on the use of PLL (Phase-Locked Loop) and is able to perform high resolution measurements despite the use of a low resolution encoder. A complete measurement system was developed fusing the proposed approach and the classic T method, allowing even the measurement of zero velocity and the determination of the shaft rotation direction. In order to validate the proposed approach, some parameters were considered to compare its performance with the performance of a classical method. To validate the proposed approach and to compare it with the classical methods, some comparison parameters were considered. The results obtained using each method are presented and discussed, as well as the comparison between them

Induction Machine Neural Estimator using Embedded System

Indirect measurement architecture for speed estimation has been presented in this paper. This system is based on neural estimator implemented on programmable system on-chip (PSoC), using C++ language, which executes speed estimator algorithm, considering a 1.0 s time interval for neural estimator. The results from experiments and simulations indubitably proved the proposed estimator good performance. This efficiency was verified by analysis, considering the following focus: estimator precision when its compared to conventional speed measurements (tachometer). Speed measurements values from the PSoC and tachometer have shown a smaller than 2% discrepancy

Design considerations for ultrasonic signals acquisition

This paper presents some considerations about uncertainty and noise related to ultrasonic transducers in time of flight estimation for wind speed measurement with pulsed transmission mode. Experimental results show the noise distribution in a measurement setup using ultrasonic transducers and the relation between signal to noise ratio, uncertainties and number of cycles used in pulsed transmission by transceiver. From these results, the project considerations for ultrasonic signals acquisition can be defined, such as number of cycles and uncertainty evaluation.

MODELAGEM MATEMÁTICA DE TRANSFORMADORES BASEADA NA RESPOSTA EM FREQUÊNCIA DOS PARÂMETROS DE MAGNETIZAÇÃO

A mathematical modeling procedure for single phase low power transformers is presented in this paper. It is based on the frequency response of the shunt parameters, taken from the electric model. The open circuit test was performed for different frequencies in four transformers, and the magnetizing parameter frequency responses were determined. It was verified that the sum of exponential functions can be employed to represent the behavior of the magnetizing parameters as a function of frequency, with notable accuracy. The results contribute to the improvement of mathematical models and circuit equivalents of single phase transformers.

Testes automatizados para caraterizaçâo de materiais magnéticos e transforamadores

Ensaios em materiais magneticos e transformadores envolvem procedimentos repetitivos e demorados que, quando realizados manualmente e em larga escala, podem conduzir a resultados imprecisos. A automacao de tarefas de controle de instrumentos e exibicao de dados garante a confiabilidade do processo e agilidade na realizacao dos experimentos. Este trabalho tem como objetivo apresentar um sistema de teste s automatizado utilizado para caracterizacao de materiais magneticos e transformadores.