Design And Construction Of A 380V/36V Stepdown Transformer

ABSTRACT

This work is on 380vac to 36vac step down transformer, which is a transformer whose secondary voltage is less than its primary voltage. It is designed to reduce the high voltage (380v) from the primary winding to 36v in the secondary winding.

As a step-down unit, the transformer converts high-voltage, low-current power into low-voltage, high-current power. The larger-gauge wire used in the secondary winding is necessary due to the increase in current. The primary winding, which doesn’t have to conduct as much current, may be made of smaller-gauge wire.

The aim of this work is to design and construct a step-down transformer power supply system with a primary voltage of 380V and a secondary voltage of 36V.

 TABLE OF CONTENTS

 TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

• INTRODUCTION
• AIM/OBJECTIVE OF THE PROJECT
• SCOPE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• APPLICATION OF THE PROJECT
• LIMITATION OF THE PROJECT
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

2.0      LITERATURE REVIEW
2.1      HISTORICAL BACKGROUND OF TRANSFORMER
2.2     CLASSIFICATION PARAMETER OF A TRNSFORMER
2.3     REVIEW OF DIFFERENT TYPES OF TRANSFORMER
2.4     OTHER TYPES OF TRANSFORMERS

CHAPTER THREE

3.0      METHODOLOGY

3.1     CIRCUIT DIAGRAM OF A STEP DOWN TRANSFORMER

3.2    BASIC WORKING PRINCIPLE OF A TRANSFORMER

3.3      TRANSFORMER CONSTRUCTION

3.4     CIRCUIT DISCRIPTION OF A STEP-DOWN TRANSFORMER

3.5   DESIGN FO THE TRANSFORMER PROPER

3.6      TURNS CALCULATION

CHAPTER FOUR

RESULT ANALYSIS

4.1  TESTING OF TRANSFORMER OPERATION

4.2 SHORT-CIRCUIT TEST

4.3 FAULT WITHSTAND

4.4 TRANSFORMER COOLING METHODS
4.5 DESIGN PHOTOGRAPH

4.6 TROUBLESHOOTING METHOD OF A STEP DOWN TRANSFORMER

CHAPTER FIVE

• CONCLUSIONS
• RECOMMENDATION

5.3     REFERENCES

CHAPTER ONE

1.1                                                        INTRODUCTION

A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. Electromagnetic induction produces an electromotive force across a conductor which is exposed to time varying magnetic fields. Commonly, transformers are used to increase or decrease the voltages of alternating current in electric power applications.

A varying current in the transformer’s primary winding creates a varying magnetic flux in the transformer core and a varying magnetic field impinging on the transformer’s secondary winding. This varying magnetic field at the secondary winding induces a varying electromotive force (EMF) or voltage in the secondary winding due to electromagnetic induction. Making use of Faraday’s Law (discovered in 1831) in conjunction with high magnetic permeability core properties, transformers can thus be designed to efficiently change AC voltages from one voltage level to another within power networks.

As a step-down unit, the transformer converts high-voltage, low-current power into low-voltage, high-current power. The larger-gauge wire used in the secondary winding is necessary due to the increase in current. The primary winding, which doesn’t have to conduct as much current, may be made of smaller-gauge wire.

For the course of this work, a step down transformer which is used to convert 220V to 12v which is main objective of the project.

1.2                                        AIM/OBJECTIVE OF THE PROJECT

Step down transformer is designed to reduce the voltage from the primary winding to the secondary winding. This kind of transformer “steps down” the voltage applied to it. The aim of this work is to construct a transformer with a primary voltage of 380V and a secondary voltage of 36V. At the end of this work:

• a transformer with primary voltage of 380V and a secondary voltage of 36V would be constructed.
• Principle of operation of a transformer would be learned
• Different types of transformer will be discussed
• Different types of Cooling systems of a transformer will be discussed

1.3                                         SIGNIFICANCE OF THE PROJECT

A step down transformer is needed to decrease the input 380 Volt electricity to 36 Volts power. It can be safely used powering 36v rated appliances.

1.4                                          APPLICATION OF THE PROJECT

Step down Transformers are also used extensively in electronic products to decrease (or step-down) the supply voltage to a level suitable for the low voltage circuits they contain. The transformer also electrically isolates the end user from contact with the supply voltage.

1.5                                                 SCOPE OF THE PROJECT

This work was carried out using step-down transformer, as evidenced by the high turn count of the primary winding and the low turn count of the secondary. As a step-down unit, this transformer converts high-voltage, low-current power into low-voltage, high-current power. The larger-gauge wire used in the secondary winding is necessary due to the increase in current. The primary winding, which doesn’t have to conduct as much current, may be made of smaller-gauge wire.

The Transformers used is often constructed in such a way that it is not obvious which wires lead to the primary winding and which lead to the secondary. One convention used in the electric power industry to help alleviate confusion is the use of “H” designations for the higher-voltage winding (the primary winding in a step-down unit; the secondary winding in a step-up) and “X” designations for the lower-voltage winding.

1.6                                           LIMITATION OF THE PROJECT

In this work, it is possible to operate either of these transformer types backwards (powering the secondary winding with an AC source and letting the primary winding power a load) to perform the opposite function: a step-up can function as a step-down and visa-versa. However, as we saw in this work, efficient operation of a transformer requires that the individual winding inductances be engineered for specific operating ranges of voltage and current, so if a transformer is to be used “backwards” like this it must be employed within the original design parameters of voltage and current for each winding, lest it prove to be inefficient (or lest it be damaged by excessive voltage or current).

1.7                                        PROJECT WORK ORGANIZATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to a 380v to 36v step down transformer.  In this chapter, the background, significance, objective limitation and problem of a 380v to 36v step down transformer were discussed.

Chapter two is on literature review of a 380v to 36v step down transformer. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed. Chapter five is on conclusion, recommendation and references.