This paper presents a program developed for calculating magnetic field intensity of high voltage transmission line and high voltage distribution lines. This program was developed with Microsoft Visual Basic and Microsoft Access program was used to store the database of the peak ratings current height and space of transmission lines. The developed program was able to calculate magnetic field intensity of high voltage transmission line and high voltage distribution lines according to 2 standards of Provincial Electricity (PEA): “A 22 kV Single Conductor Circuit High Voltage Distribution System” and “115 kV Single Conductor Circuit High Voltage Transmission System”. The program was able to select structure of the electrical system to be calculated as well as types and specification of Transmission line from the stored database that corresponded with the structure. The calculated output waveforms were displayed on computer monitor. Results from the developed program enable more convenient and faster calculations of magnetic field intensity of high voltage transmission line and high voltage distribution lines and are useful for analysis of possible impacts on electric and electronic devices.

The purposes of this study were to investigate the heat transfer and the vibration characteristics caused by front and back vented brake disc which had physically different shapes affecting braking distance. In accordance with the theory of heat transfer the heat transfer rates of two types of brake disc were different and played an important role in the deformation during usage. The single dynamometer was conducted to the experimental work as an engineering tool with boundary conditions according to JASO C406 standard. One degree of freedom (DOF) acceleration signals on the brake caliper were analyzed. The results obviously discovered that the back vented brake disc was able to reduce the vibration up to 43.5% comparing to the front vented brake disc in case of the braking temperature 200C initial breaking speed 50 km/h and the hydraulic pressure of 4 MPa. Besides the hydraulic pressure at 4 MPa generated the maximum vibration. Furthermore the initial braking speed and the braking temperature were also the important factors. Regarding braking distance results the results of the experimental work obviously discovered that the back vented brake disc created braking distance shorter than front vented brake disc. Besides there were important factors as braking temperature hydraulic pressure and initial speed of braking. Especially the high braking temperature caused an increase of deceleration and a decrease of braking distance. Moreover the high hydraulic pressure produced a deduction of braking distance and an increase of deceleration. Finally the initial speed of braking directly varied to the braking distance

Admittedly a disc brake plays an important role in the auto part industry since it concerns directly with safety. Therefore the wide range of disc brake has been designed in order to develop its heat ventilation. There are two physical kinds of brakes: front-vented disc brake and backvented disc brake. As a result such difference affects directly to the heat ventilation which is a vital factor of the brake’s capability. The project team recognizes its importance and tries to create the test to find out the temperature diffusion of the disc brake with the hope to evaluate the coefficient of the heat convection varied by the temperature changing in both kinds of brakes under the forced heat convection in the steady condition. However the steady heat conduction and radiation value will not be counted because it is insignificant. The JASO C406: 2000 Standard is adopted as a guideline in the test. The outcome coefficient of heat conduction will be used in the simulation via the Finite Element Method (FEM) in order to study the temperature diffusion and heat ventilation of both kinds of brakes at each temperature level. Consequently the experimental work reveals then the heat convection coefficients of both kinds are unidirectional. The heat convection coefficient of the front-vented disc brake is 4.40 % in average higher than that of the back-vented disc brake. From the simulation the front-vented disc brake can ventilate the heat better than the back-vented disc brake at 3.02 % in average. It can be summarized that the front-vented disc brake has more temperature difference than the backvented disc brake. Hence the front-vented disc brake likely gets more stress from the temperature than the back-vented disc brake and might be damaged during the operation more than the another type.