Design And Construction Of A 220-110V Step Down Transformer

This work is on 220vac to 110vac power supply using transformer, which served as 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 110v 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 110V.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM AND OBJECTIVE OF THE PROJECT
• CONTRIBUTION TO KNOWLEDGE
• LIMITATION AND SCOPE OF THE PROJECT
• METHODOLOGY
• DEFINITION OF TERMS
• PROJECT WORK ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• INTRODUCTION
• HISTORICAL BACKGROUND OF TRANSFORMER
• CLASSIFICATION PARAMETERS OF TRANSFORMER
• REVIEW OF DIFFERENT TYPES OF TRANSFORMER
• OTHER TYPES OF TRANSFORMERS

CHAPTER THREE

• INTRODUCTION
• CIRCUIT DIAGRAM OF A STEP DOWN TRANSFORMER
• MATERIALS USED

CHAPTER FOUR

• SYSTEM DESIGN METHODLOGY
  • INTRODUCTION
  • BASIC WORKING PRINCIPLE OF A TRANSFORMER
  • CIRCUIT DISCRIPTION OF A STEP-DOWN TRANSFORMER
  • M.F EQUATION OF A TRANSFORMER

CHAPTER FIVE

5.0      CONSTRUCTIONOF THE DESIGNED PROJECT

• INTRODUCTION
• CHOICE OF MATERIAL
• CONSTRUCTION OF THE PROJECT
• TESTING OF TRANSFORMER OPERATION
• DESIGN PHOTOGRAPH

CHAPTER SIX

6.0      CONCLUSION, SUMMARY, RECOMMENDATION AND PROBLEM ENCOUNTERED

• CONCLUSION
• SUMMARY
• RECOMMENDATION
• PROBLEM ENCOUNTERED
• 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.

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 110v was constructed which is main aim of the project.

1.2                                                  PROBLEM STATEMENT

Some imported electronic gadgets comes with voltage rating of 110VAC as the input voltage rating when trying to use them in 220VAC which is Nigeria mains supply, it becomes dangerous to the user and the gadget. The problem led to the invention of 220 to 110VAC step down transformer. This device is 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.

1.3                                        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 110V. At the end of this work students involved would be able:

• To build a transformer with primary voltage of 220V and a secondary voltage of 110V would be constructed.
• Know the Principle of operation of a transformer would be learned
• Know different types of transformer.

1.4                                        CONTRIBUTION TO KNOWLEDGE

The power in a transformer is measured using the product of voltage and current. The power in a transformer is rated in Volt – Amps VA (or Kilo Volt – Amps kVA for larger transformers).

Ideally, the power in any transformer is constant i.e. the power available at the secondary of the transformer is same as the power at the primary of the transformer.

This is even applicable to a step down transformer. But, since the voltage at the secondary of a step down transformer is lesser than that at the primary, the current at the secondary will be increased in order to balance the total power in the transformer.

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.

This device has a long mains lead which makes it possible to be used at homes and a protecting fuse in case of wrong voltages or currents.

1.5                               LIMITATION AND 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.

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).

1.6                                                        METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. The operation of the device was studied.

• Gathering of materials such as copper wires and iron core

1. Design and calculation for the work was carried out.
2. Construction of the whole circuit was carried out.
3. Finally, the whole device was cased and final test was carried out.

1.7                                                  DEFINITION OF TERMS

Bushing — An electrical insulator that is used to control the high voltage stresses that occur when an energized cable must pass through a grounded barrier.

Step-down transformer — A transformer where the input voltage is greater than the output voltage.

Step-up transformer — A transformer where the input voltage is less than the output voltage.

Autotransformer — A transformer in which part of the winding is common to both the primary and the secondary circuits.

Core losses — Losses (expressed in watts) caused by magnetization of the core and its resistance to magnetic flux. Also called no-load losses or excitation losses. Core losses are always present when the transformer is energized.

High voltage windings — In a two-winding transformer, the winding intended to have the greater voltage. Usually marked with ‘H’ designations.

Hysteresis — The tendency of a magnetic substance to persist in any state of magnetization.

Impedance — The retarding forces of current in an AC circuit; the current-limiting characteristics of a transformer. Symbol = Z

kVA — Kilovolt-ampere. Designates the output that a transformer can deliver for a specified time at a rated secondary voltage and rated frequency without exceeding the specified temperature rise. When multiplied by the power factor, will give kilowatts or kW. 1000 VA = 1 kVA

Lamination — Thin sheets of electrical steel used to construct the core of a transformer.

Load — The amount of electricity, in kVA or volt-amperes, supplied by the transformer. Loads are expressed as a function of the current flowing in the transformer, and not according to the watts consumed by the equipment the transformer feeds.

Load losses — I²R losses in windings. Also see conductor losses.

Low voltage winding — In a twowinding transformer, the winding intended to have the lesser voltage. Usually marked with ‘X’ designations.

Secondary Taps — Taps located in the secondary winding.

Secondary Winding — The transformer winding located on the energy output (load) side.

1.8                                        PROJECT WORK ORGANISATION

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 220v to 110v step down transformer. In this chapter, the background, significance, objective limitation and problem of 220v to 110v step down transformer were discussed.

Chapter two is on literature review of 220v to 110v 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.