Braking system is the main of safety for motor vehicle. It uses to slow down or stop of vehicle movement. Normally braking system can not to adjustable in the recently. The brake efficiency depends up on to 3 factors by the perfection of brake equipment friction coefficient of road surface and the brake proportional. The factor of the perfection of brake equipment and friction coefficient of road surface can not be control. But in case of the brake proportional can be set up to suitable. In the other hand if the brake ratio is unsuitable the driver may be risk to danger from the loss of vehicle control. From this reason the aim of project is to study of the brake proportional affected to vehicle control. By the test condition consist of 2 cases: braking performance testing and vehicle stability testing. In case of braking performance testing is consider to deceleration braking distance and time of braking. For the vehicle stability testing is determined with yaw angle pitch angle sideslip angle and wheel lock up condition. However the bolt of testing is the road test and using the FMCSA standard for the testing guideline. The result of the braking performance testing shown the maximum deceleration was appeared on brake proportional 80:20. But the braking distance and time of braking are least because of the non-continuously of deceleration from the driver. Therefore the braking distance and time of braking depend on the continuously of deceleration. In term of vehicle stability testing discovered to the each of brake proportional are risk to danger for the driver especially on the 100:0 because of the value of sideslip angle is more than the critical point and the rear axle is lock up.

The aim of this research is to create the center of mass testing machine for vehicles with maximum mass 3000 kilograms. By the performance of this machine is able to determine the center of mass 3 axis by horizontal longitudinal and vertical. On the other hand the verities of mass from 50 to 250 kilograms and the several of weight distribution at horizontal and longitudinal are applied to the condition of testing for reasonable to the position of the center of gravity for vehicle. The result of research discovered to the performance of center of mass tester was activated following to test conditions. Furthermore the position of the horizontal of center of gravity depends on the weight distribution at horizontal axis and an increasing of mass under non-uniform along the longitudinal and horizontal axis. In term of the position of the longitudinal of center of gravity the weight distribution at longitudinal axis and an increasing of mass rate are points. Otherwise the weight distribution at longitudinal axis and an increasing of mass are effect to the position of the vertical of center of gravity.

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. Thus this project has designed a back-vented brake disc which is difference the current one (front-vented) and tried 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 back-vented 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. Therefore this is tendency that the back-vented is safer than the front-vented brake disc for usage.

The aim of this research is to study the varieties of weight density distribution affect to the center of mass and vehicle stability. The weight density distribution tester was designed and changed the position of mass. Base on the center of mass is main points of vehicle stability. On the other hand FMCSA standard was applied to field test for considering of the brake performance and vehicle stability. The results of research discovered to the mass distribution on horizontal plane and fixed position Y1 are absolutely influence under an increasing 50 kilograms of mass condition. For the mass distribution on longitudinal plane and fixed position Z2 and Z3 are affected to the increasing of mass 100 and 150 kilograms respectively. Otherwise under an increasing of mass 200 and 250 kilograms there is non-influence to the weight density distribution. In term of the braking performance it’s depends on the lateral mass distribution especially the center position of mass installed on longitudinal and horizontal plane and close up on the front axle (Y2). For the vehicle stability results the position (Y2) is the highest influence for yaw rate and sideslip. Otherwise the position (Y3) or the position of mass installed on longitudinal plane and nearly at the left wheel on the rear axle. Additionally wheel lock-up condition was appeared on the front axle only. Because the behavior of the weight distribution on front axle was decreased lead to mass distribution on longitudinal plane.

In this article the construction of a high-frequency high-voltage commercial flyback transformer to supply an input voltage for a tesla transformer is proposed. The purpose of a demonstration is a breakdown through the air gap of electrode. To confirm the proposed method the design of control of a flyback converter by using a commercial flyback transformer is rated with a 10 to 15 kV output voltage to supply a tesla transformer at a rated 30 kV and 120 kHz. The experimental results of an output breakdown design of the electrode and the setting for a 1 cm space are constructed. The electrodes consisted of the following: sphere–sphere electrode plane–plane electrode sphere–plane electrode and rod–plane electrode. It was found that there was a breakdown at the output electrode in all cases. Accordingly there was a breakdown with a 2 cm sphere diameter with reference to the IEC 60052-2002 standard; after that it was compared with the standard table and the atmospheric and temperature at the laboratory were adjusted resulting to a high voltage equal to 31.5 kV.