Design And Construction Of A 220V/50V Step Down Transformer With Power Rating Of 500VA

ABSTRACT

This work is on 220vac to 50vac power supply using transformer. A Transformer is a static apparatus, with no moving parts, which transforms electrical power from one circuit to another with changes in voltage and current and no change in frequency. There are two types of transformers classified by their function: Step up Transformer and Step down Transformer. In this work we are looking at a step down transformer whose secondary voltage is less than its primary voltage. It is designed to reduce the voltage (220v) from the primary winding to 50v 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 220V and a secondary voltage of 50V

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• AIM AND OBJECTIVE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• APPLICATION OF THE PROJECT
• SCOPE OF THE PROJECT
• LIMITATION OF THE PROJECT
• PROJECT ORGANIZATION

CHAPTER TWO

LITERATURE REVIEW

• REVIEW OF THE STUDY
• HISTORICAL BACKGROUND OF THE PROJECT
• CLASSIFICATION PARAMETERS OF TRANSFORMER
• REVIEW OF DIFFERENT TYPES OF TRANSFORMER
• OTHER TYPES OF TRANSFORMERS

CHAPTER THREE

SYSTEM DESIGN METHODOLOGY

• CIRCUIT DIAGRAM OF A STEP DOWN TRANSFORMER
• BASIC WORKING PRINCIPLE OF A TRANSFORMER
• TRANSFORMER CONSTRUCTION
• CIRCUIT DESCRIPTION OF A STEP-DOWN TRANSFORMER
• M.F EQUATION OF A TRANSFORMER
• DESIGN CALCULATION

CHAPTER FOUR

• TESTING, MEASUREMENT AND RESULTS
  • TESTING OF TRANSFORMER OPERATION
  • SHORT-CIRCUIT TEST
  • FAULT WITHSTAND
  • TRANSFORMER COOLING METHODS
  • DESIGN PHOTOGRAPH
  • HOW TO CHECK A STEP DOWN TRANSFORMER

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCE

CHAPTER ONE

1.0                                                        INTRODUCTION

1.1                                         BACKGROUND OF THE PROJECT

Power supply supplies electric energy to an electrical load. The primary function of a power supply is to convert one form of electrical energy to another and, as a result, power supplies are sometimes referred to as electric power converters. Some power supplies are discrete, stand-alone devices, whereas others are built into larger devices along with their loads. Examples of the latter include power supplies found in desktop computers and consumer electronics devices.

Every power supply must obtain the energy it supplies to its load, as well as any energy it consumes while performing that task, from an energy source. Depending on its design, a power supply may obtain energy from various types of energy sources, including electrical energy transmission systems, energy storage devices such as a batteries and fuel cells, electromechanical systems such as generators and alternators, solar power converters, or another power supply.

All power supplies have a power input, which receives energy from the energy source, and a power output that delivers energy to the load. In most power supplies the power input and output consist of electrical connectors or hardwired circuit connections, though some power supplies employ wireless energy transfer in lieu of galvanic connections for the power input or output.

However, in this work, a power supply was design using a transformer which serves as a step-down transformer. A step down transformer: is one whose secondary voltage is less than its primary voltage. It 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.

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 of 220V to 50v was constructed 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 220V and a secondary voltage of 50V. At the end of this work students involved would be able:

• Build a transformer with primary voltage of 220V and a secondary voltage of 50V would be constructed.
• Know the Principle of operation of a transformer would be learned
• Know different types of transformer will be discussed
• Know different types of Cooling systems of a transformer will be discussed

1.3                                         SIGNIFICANCE OF THE PROJECT

1. A step down transformer is needed to decrease the incoming 220 Volt electricity found in most parts of the world to 50 Volts power. It can be safely used powering 50v rated appliances.
2. Useful in stepping down the voltage, thereby making transmission power easier and cheaper

• More than 99% of efficiency

1. Provides varied voltage requirements
2. Low Cost
3. High Reliability

• High Durability

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. Other applications of Step Down Transformers includes:

• In main adapters and chargers for cell phones, stereos and CD players
• To step down the voltage level in transmission line
• In welding machines by reducing voltage and increasing current.
• In televisions, voltage stabilizers, inverters, etc.

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 vice-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 ORGANIZATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied,  chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.