Efficient Power Response Characteristics of 2KVA Low Cost Inverter under Resistive Loads and Inductive Loads

The paper discussed the design of low cost inverter using SG3525A IC and IRF3205 MOSFET in H-Bridge configuration. The implementation of the real construction involved the use of IC SG3525A for generation of output pulses; the totem pole arrangement of transistors was used in the driver section of the inverter to boost signals as well as switching purposes. The H-bridge configuration was employed to effectively switch the four MOSFETs, this switching produced an alternating potential of 220V. Pre-set conditions such as load condition, low battery cut, overcharge cut and constant output were set at 1700W, 10V, 13.3V and 220V respectively so as to ensure effective and long lasting usage of the inverter. The battery used for the operation of the inverter was 12V maintenance free battery in order to reduce the cost of using the inverter. The various tests carried out on this inverter were tests on inductive loads, resistive loads, home appliances, overload condition, low battery and charging control. The aim of this work is to achieve inverter design analysis under resistive loads and inductive loads for efficient power usage at lowest possible cost. This was achieved by connecting various resistive and inductive loads on the inverter. The results show that the system can operate under both the resistive and inductive loads but operates better under resistive loads, the reason for this is that inductive loads always draw large currents during start-ups which always result to power losses. Graphs were plotted and analyzed; the results also showed that this inverter can take up to 1700W of resistive load and inductive load of 1020W. The inverter produced no humming sound from inductive loads and home appliances such as fan, television, refrigerator e.t.c that were within its maximum capacity of 1700W.

An Experimental Study on the Effects of Burst Pressure on Air Blast Development in a Blast Wave Simulator

Due to the extensive use of explosive devices in military conflicts, there has been a dramatic increase in life-threatening injuries and resultant death toll caused by explosive blasts. In an attempt to better understand the blast waves and mitigate the damages caused by such blast waves, various devices/systems have been developed to replicate the field blast scenarios in laboratory conditions. The East Carolina University Advanced Blast Wave Simulator (i.e., ECU-ABWS) is one such facility that can reproduce blast waves of various shapes and profiles. The peak overpressure of a blast is the key factor that causes the greatest number of damages, and it is essentially determined by the burst pressure of the blast. Therefore, a better understanding of the effects of burst pressure on blast generation and development is strongly desired to develop safer and more effective blast mitigation technologies. In the present study, a series of experiments were carried out in the ECU-ABWS to characterize the blast waves generated under different burst pressure conditions. While the incident (side-on) pressures at multiple locations along the blast propagation direction were measured using a temporally-resolved multi-point pressure sensing system, the time-evolutions of blast wave profiles were also qualitatively revealed by using a high-speed Schlieren imaging system. The synchronization of pressure sensing and Schlieren image acquisition enables us to extract more physical details of the dynamic blast wave development under different burst pressure conditions by associating the incident pressures and shock wave morphologies. In this study, the different burst pressures were achieved by altering the thickness of the membrane separating the driver section of pressurized gas and the driven section of air at atmospheric pressure. It is found that there is a linear relationship between the burst pressure and the peak overpressure. As the burst pressure increases (by increasing the membrane thickness), more clearly defined shock wavefronts are also observed along with the peak overpressure increase.

Some Consideration on the Aerodynamic Design of Blast Wave Simulator Using a Shock Tube System

Reduction methods of the jet flow associated with simulated blast waves by blast wave simulators are investigated by computational simulations. First, the cause of the jet flow is discussed. After that, the influence of the nozzle angle and the volume of the driver section on the jet flow are investigated. The obtained results show that the jet flow is caused by vortices which are generated at the edge of the nozzle and that the jet can be reduced by decreasing the driver section. Furthermore, the nozzle with the moderate angle reduces the jet flow near the nozzle exit and the nozzle with the widest angle reduces the jet flow far from the nozzle exit. These results indicate reducing the driver section and using the proper nozzle angle according to the distance from the nozzle exit are effective for reducing the jet flow.

Perancangan Alat Penyambung Universal pada Transporter Mini Tandan Buah Segar Kelapa Sawit

<em>Every palm oil plantation has different characteristics. In Indonesia, some of the palm oil plantations are unique because of its peaty, muddy, and bumpy features. Today, the existing Fresh Fruit Bunch (FFB) transport equipment is rigid and unable to follow the contour of outline of plantation ground, which limits its mobility. Therefore, it is necessary to design FFB transport equipment that offers ease of mobility. The new design has a universal joint feature that connects the front of part of the equipment (driver section) with the load carrier part (rear part). The design includes three-dimensional images with its simulations, two-dimensional images and the strength analysis of the joint. Both design drawings and strength analysis are carried out using SolidWorks engineering software. The result is a design of a universal joint with a dimension of 0.2 m in length and 0.15 m in width, and is capable of rotating in two directions; each at 30 degree on Y axis and 16 degree on X axis. All components of the universal joint are SS400 steel which has a tensile strength of 250 MPa. Calculation of strength with a tensile load of 1 ton results in a safety factor of 833. This safety factor ensures the maximum life span and strength of the universal joint.</em>

Compact Switched Mode Power Supply for Medium Voltage Drives

A switched mode power supply (SMPS) with multiple outputs has been developed which satisfies the need of isolation of control circuit power supply and driver section power supply for a medium-voltage electrical drive. It means that there is no need of extra components for isolation. For this SMPS, fly-back converter topology along with current mode control method is selected and its performance is observed for line, load as well as cross regulation with other tests. This SMPS generates multiple outputs of +5 V, +24 V, +/- 15 V and five +24 V isolated output voltages.