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DESIGN AND CONSTRUCTION OF AUTOMATIC PHASE SELECTOR

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND OF STUDY
As the growing population of human race widens the gulf between energy supply and energy demand, the imbalance in energy availability sent researchers into excavating for a way of settling this age long squabble. A lasting solution is vested on alternative use of the renewable energy source, a project that is yet to be widely applied. Hence, the continuation of the unsettled yearns for sufficient power. Consequently, the power lines are frequently over loaded resulting to a trip of power by the action of switch gears or by the load shading process undertaken by the distribution authorities.
Since it is crystal clear that some institutions such as health related institutions and some other delicate systems should not be allowed to suffer equally with their counterparts, Automatic Phase Selector is used to sustain energy consumption in the time of phase trip. The design of this circuit involves the use of automatic switches but the details of design varies from place to place, time to time and also depends on the type of load involved.
This project involves the use of transistor driven relays to affect the change of phase whenever the voltage condition becomes intolerable in the previous phase connected.

The intelligent phase selector is a system that is capable of comparing three phases and switching automatically to any of the three phases. The system consists of three main parts namely; the transformer, comparators (which is the brain of the system) and electrical switching device (relay).
The transformer used here is the step down type of transformer (it step down 240v to 12v) and these transformer is feed in with different phase voltage, rectified and smooth. Then fed in to a voltage regulator that has positive output. The regulator outputs were connected to comparators. Here the comparators are three in number. We call the comparators the brain of the system because these comparators are connected in a way that each of them will give out an output.
The relay in the system is where the output voltage is connected. In this project we even went as far as using pictures for illustration of some components.

1.2 AIMS/OBJECTIVES OF THE PROJECT
The analysis of this project cannot go without enumerating the goals meant to be achieved in the pursuit of the work. These objectives include:-
i. To develop a simple low cost device aimed at easing the prevalent burden faced by delicate offices, parastatals and institutions who need very low but constant power supply. Since supply is always on along the distribution lines
that supply such sites, what pesters on the progress of work thereof is always the unwarranted trip of phases due to power usage from neighboring consumers. The automatic phase selector therefore, erases this setback form the face of progress of work in such offices.
ii. To stimulate the interest of upcoming students to take up research not only in their field of study “Electrical/Electronic Engineering” but also to extend their arms to other disciplines, thus enhancing the versatility of Electrical/Electronic Engineering.
iii. To create awareness that will stimulate the interest of fellow students who intend to take up research topic on automatic switch of any type.

1.3 RELEVANCE OF THE PROJECT
The issue of selecting or switching over manually is now a thing of the past. Nowadays we know that homes and offices enjoy steady power supply once the three phases are available (i.e. red yellow and blue phases). Is just a question of making a quick and automatic three phase selector?

1.4 SCOPE OF THE PROJECT
The scope of the project covers aspects like the features of automatic three phase selector, its applications, and its operations. Its advantages and its components. Finally, it covers the importance on the need of automatic three phase selector
and contributions toward a greater sharing load balance and a better three phase power distribution and monitoring for domestics consumers.

1.5 LIMITATIONS
Owning to the nature of this project, the research centers and the resources were not easy to come by within the immediate environment. Some of the limitation encountered on the course of this project include financial and time constrains which did not really take much room for additional capacity beyond what is at hand.

1.6 TARGET BENEFICIARIES
This project will provide lasting solutions to the heavy losses incurred by commercial institution, industries, hospitals, airport etc caused by poor manual selector means and efficient switching facilities. It will also be of use in our household because poor selector of phase manually causes damage to our household equipment example electronics like television,radio,videoplayer etc and electrical appliances like refrigerator, air condition, fans just to mention but a few. Finally another target is to eliminate the loss of human life due to manual selection of the three phases.

1.7 SIGNIFICANCE OF STUDY
The significance of this project work cannot be overemphasized. This is because the number of lives that has being lost to the hand of interruption of power in health institutions and the like is not negligible. Delicate appliances have become the main victim of this artificial circumstance. The applicability of the outcome of this research work in several facets of human endeavor makes this work of real importance to humanity.
The use of the device produced from this research work would help to reduce human labor and hazard, going by the fact that many have been handicapped by electric shock because of the attempt they made to select another phase, and that the handicapped are helpless and cannot change phase.

1.8 ACHIEVEMENT OF THE CONSTRUCTION OF THE PROJECT
As long as electrical generation and construction is must in everyday activities, electrical power consumption is expected to be reliable and constant supply. Therefore, what we tend to achieve from this project is;
1. To have constant power supply.
2. To have quick operation i.e. phase selection
3. Reliable power supply
4. Easy operation
5. Avoidance of risk in doing manual changeover or switch