Héctor Cadavid Ramírez

Experimental Results of a Cost-Effective Ozone Generator for Water Treatment in Colombia

Obtaining high-quality cost-effective water, minimizing the public health risk generated by pathogenic elements or disinfection sub-products such as trihalomethane and/or chlorophenol, has made necessary the use of technologies different to chlorination. In this paper, we present the implementation of a high-voltage, high-frequency flyback inverter to generate ozone, and outline the main characteristics and uses of a prototype of water ozonation from a well for a hospital in Colombia. With the prototype, the ozone dose can be adjusted through the duty cycle modulation; switching was done with a Mosfet and the voltage signal was increased with a ferrite technology transformer. The source is characterized by its simplicity, good performance and low cost.

Vigencia del método de Roth para la determinación de fuerzas de cortocircuito en devanados de transformadores

Contexto: Debido a la dificultad para realizar la prueba de aptitud al cortocircuito en transformadores de gran potencia, la norma IEC 60076-5 2006 de la Comision Electrotecnica Internacional acepta como metodo alternativo la estimacion de las fuerzas y esfuerzos a traves de calculo y consideraciones de diseno. Metodo: En este articulo se presenta la implementacion del metodo analitico de Roth para el calculo de las fuerzas axiales y radiales de cortocircuito en un transformador trifasico con nucleo tipo columnas de 630kVA. Resultados: Las fuerzas maximas obtenidas con el metodo de Roth son comparables con las calculadas a traves de metodos modernos para el diseno de transformadores como el metodo de elementos finitos, las diferencias entre los calculos fueron minimas a excepcion de la fuerza axial maxima del devanado de baja tension. Conclusiones: Aunque el metodo de Roth es una herramienta tradicional para solucion de problemas de electromagnetismo, este es adecuado para hacer una estimacion rapida y sencilla de parametros magneticos y fuerzas de cortocircuito en transformadores.

Analysis of the Magnetic Field Homogeneity for an Equilateral Triangular Helmholtz Coil

This paper presents a mathematical analysis of the magnetic field homogeneity for an Equilateral Triangular Helmholtz (ETH) coil. The magnetic field analysis is based on the Biot-Savart law in which a Taylor series approximation is performed to obtain the analytical distance that complies with the Helmholtz condition between the pair of coils. This is done to compare the magnetic field distributions of the ETH and the Circular Helmholtz (CH) coils for the parameters side length (2a, √ 3a) and radius (a) respectively. Furthermore, an approximate expression of the magnetic field homogeneity with regard to the side length parameter is obtained and finally a computational model of the ETH coil using COMSOL R