ABSTRACT
Transformers are electromagnetic energy transformation devices which operate on the principles of electromagnetic induction. The devices transform alternating current voltage from one value to another at a constant frequency. This work reviews the development of these functional devices using locally available materials in Nigeria. The design stages, material selection, manufacturing techniques, performance parameters such as efficiency, voltage regulation and power factor were also discussed. Some applications of the locally developed transformers were presented. The possibilities of producing larger power transformers for electrical power transmission and…
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INTRODUCTION

The production of lightning arresters using locally available materials in Nigeria was carried out Usifo and Edeko (1998). They used a mixture of haematite and calcium carbonate to produce the arrester. Usifo (2001) conducted s further work on these materials which resulted in the present day Oriaghe (named after the inventor) lightning arresters which have the same characteristics as that of the silicon carbide based lightning arrester. It would be interesting to note that these lightning arresters were the spark gap…
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INTRODUCTION
The protection of electrical appliances, installations and personnel against surge voltages resulting from lightning and switching of reactive loads is not new. Benjamin Franklin is a pioneer scientist in the study of lightning (Gupta, 2007). After his famous experiment of flying kite in thunder cloud in 1745, he proved then that lighting stroke is caused by the discharge of electricity. He invented lightning rods for fixation on tall building and grounding it for protection against lightning strokes.

INTRODUCTION

Zinc oxide varistors are voltage dependent resistors which exhibits nonlinear current-voltage characteristics. The non ohmic property, current handling capability, transient energy absorption capability, response time and high nonlinear coefficient make it more suitable for voltage surge suppression. Varistors are produced by advance ceramics technology. Different kinds of techniques for its production are available elsewhere (Lagrange, 1991; Harris, 1999).