DESIGN AND CONSTRUCTION OF VARIABLE TRANSFORMER(VARIAC)

ABSTRACT The design and construction of 0.75KVA variac ranging from 0 digital display was carried out due to the fact that every electrical, electronic and laboratory appliances/equipment are designed and manufactured to operate based on the expectation that the input voltage would be at certain value. In Nigeria, household electrical/electronic appliances and also laboratory equipment are most time under threat of low voltage supply. Since the electric power supply/ distribution companies are unable to provide the consistent and adequate demanded by these sensitive appliances. The design and construction of a 3000VA variac (variable transformer) with an input voltage of 230V to give an output of 0-300V is aimed at providing solutions to this driving issue of low voltage and also to update in the growing trend of digitalization using a digital display. The method applied to achieve this project include faraday's law of induction, ohms law, e.m.f equation of transformer and voltage transformer ratio (k), where the number 450 turns and the secondary is 450 turns (approx.). The major components used to achieve this work are the copper wires and the laminated steels (core) also known as the toroidal core. The designed and constructed variac was tested with an input of 230V and the output result of 300Vmaximum was confirmed ok. If designed and properly constructed with standard electrical components and materials it could be used in sub up for distributions of electricity. It should coils, higher rated toroidal core and attached an indicator to indicate with beep sound when it is being overloaded above its capacity.