Design and Construction of Automatic Change-Over Switch

Design and Construction of Automatic Change-Over Switch

Table of Content

Title Page
Certification
Dedication
Acknowledgment
Table Of Contents
Chapter One
1.0 Introduction
1.1 Back Ground
1.2 Aims/ Objectives
1.3 Scope Of Limitation
1.4 Definition Of Terms

Chapter Two
2.0 Literature Review
2.1 The Power Transformer
2.2 The Relay
2.3 Contactors
2.4 Switches
2.5 Capacitors
2.6 Diode
2.7 Indicator Lights (Light Emitting Diodes)
2.8 Circuit Breaker
2.9 Voltmeter
2.10 Power Supply

Chapter Three
3.0 Construction
3.1 Circuit Diagram
3.2 Block Diagram
3.3 Contactor Wiring Diagram
3.4 Diagram Of The Casing

Chapter Four
4.0 Testing And Evaluation
4.1 Testing
4.2 Evaluation
4.3 Trouble Shooting And Remedy
4.4 Maintainability

Chapter Five
5.0 Conclusion
Reference

Chapter One

1.0 INTRODUCTION

As the zeal for change over on public power supply and stand-by generator increases, Engineers have researched deep into the different ways and methods of achieving power change-over both manual and automatic types.

It may not be considered a serious issue in some places where supply is up to 90% constant or where intermittent outage causes no great damage. However, places like business centers, industrial areas, and even cold rooms need almost 100% power supply. So in this case there is a need to provide a standby power supply in the event of a power outage. The important thing is to make sure an effective standby power supply that is constant and reliable is provided to eliminate the problem of long time outages.

Before, this time, changeovers are operated manually, thereby making it difficult for power continuity without time wastage. This is because an operator must always be available at any point in time. This manually operated change-over switch has two switchable positions-(main and generator) an arm is also provided from where the operator can have access to the switching. Here, the effectiveness, i.e. the fastness of the switching anytime power needs to be changed is slow and largely depends on the operator, which means that the system will be ineffective whenever the operator is not available.

The second generation of change over switch was made semi-automatic in which the main power supply directly powers the contactors.

This arrangement is made in such a way that if the main power supply fails, the contactors will all drop, leaving the supply to the generator position. The effectiveness of the system will now depend on the operator to start the generator on time.

The main problem suffered by the manual and semi-automatic systems is that the operator must have been continuously being on duty for it to be very effective. This depends on a fully closed loop system to operate.

With more research by the scientists and engineers to improve on the earlier ones, present-day technology has made it possible for the change over switch to be more effective and fast with less labor more improvements have been made in terms of several designs, using the closed-loop system at feedback control. Some also use comparators, logic circuits, and electronics timers to achieve the task.

The design of this project is in such a way that control or switching is done without any noticeable sign. It uses a combination of comparators digital switches (relays) and electromagnetic switches to achieve a very fast and effective change-over in the case of power failure. This type of switch does not depend on any operator to function well.

1.1 BACKGROUND

The background to this project work is traced to the intense demand of the populace and industries, residential homes, and much more demand for change of power supply switch for effective and continuity of power supply without a notice interruption or delay in such process to any alternative supply if the main supply goes off.

Earlier to this time, such a process is manually operated or not in use at all. The manual type which is always strenuous and time-delayed was a little bit useful but not to a satisfactorily level. More levels and expenses are always required to meet up with the time factor and effectiveness required of this process of change over. These expenses and labor could not be afforded by some individuals and industries that needed to practice this changeover.

About this solutions were suggested to improve the process, so the idea of changing or transforming the manual operated to automatic was discovered and engineers went into work immediately and came up with this automatic change over switch. But the demand for this equipment was much that something must be done to meet up with increasing demand. But this increase in demand topples the decrease in supply due to the cost of securing this equipment. The students went into this project to find out how mass production could reduce the increase in demand or meet up with the demand. They now decide to go further single-handedly produce this work and see how far it can be done without the help of an industrial machine.

After the approval, we went into market survey and evaluation of the components, after a good study of the circuit diagram. The rating of the equipment was also considered. A lot of considerations were made based on the fluctuating nature and inconsistency of our main supply source. The cost of procuring the system was put together and found out that it is less costly and easy to operate. The users can experience change oversupply without input or extra labor.

With all these considerations and studies we decided to put together this project.

1.2 AIMS/OBJECTIVES

The primary aim and objective of this project work among other things are:

a) To see how the problems of power change over can be solved with less capital and less labor.

b) To make sure that an average person can reach the equipment by the evaluation of the cost of production of this project.

c) To check the effectiveness of this work and how fast it can work without risk or extra labor or shock to personnel.

It is also aimed at improving the availability of power supply at any point in time with this equipment, due to its automatic nature. This is because the automatic nature of this project makes it unnoticeable at the output or the load.

This equipment when used will solve the problem of power outages suffered or delayed in change over suffered by many industries and business centers where power failure are greatly felt and can cause a lot of regrets, because the information is lost severally because of power failure, especially in business centers. This work, therefore, remedies these problems but can be regrettable.

1.3 SCOPE OR LIMITATION

The scope or range of this project work is as wide as 2.5KVA as the rating. This means that it is capable of standing any input of the range from any source especially generator sets and can give an output of 220-230Volts.

With this rating of 2.5KVA and a voltage of 230Volts, this work can stand any load.

The limitation is within the prescribed output /input range. In other words, an increase in the input could cause some damage to the components.

Again, a circuit breaker was provided to protect the circuit from damage due to voltage surge or output fault, or load fault.

The current rating is of 10.9Amps which is enough to withstand any load within the range.

1.4 DEFINITION OF TERMS

Generally, a change over switch is a system that could be manually or automatically operated, that changes one source of power supply to another source in the case of failure from either of the two sources.