ABSTRACT
The main aim of any electric power supply in the world is to provide uninterrupted power supply at all times to all its consumers. Although, in developing countries, the electric power generated to meet the demands of the growing consumers of electricity is insufficient, hence power instability and outage.
Power instability or outage in general does not promote development in the public and private sector. The investors do not feel secure to come into a country with constant or frequent power failure. These limit the development of industries. In addition, there are processes that cannot be interrupted because of their importance for instance, surgery operation in hospitals, transfer of money between banks and lots more.Power instability and outage in developing countries (Nigeria) creates a need for alternative sources of power to backup the mains supply.
Automatic changeover switches find a wide application scope wherever the reliability of electrical supply from the utilities is low and it is used in lighting/motor circuits wherever continuity of supply is necessary, for switching to an alternative source from main supply and vice versa.
This project is a design of an automatic changeover switch. This means that when there is any mains failure, the automatic changeover switch will change to an alternative power supply (Generator), and back to the main supply when it is restored.
  The purpose of this project is to maintain constant supply to the main circuit that is being supplied by making-up for the time lapse or delay that usually accompanies the manual switching from one source to another.
The design comprises of the power connection circuit and control connection circuit. The main components to be
used include; contactors, relays and timer.