ABSTRACT
Automatic changed-over for mains and generator(s) is a system designed to achieve the
changing over of power supply source to an alternative source of supply (generator)
whenever there is mains failure. This is achieved without the interruption of any human
being. When the main is restored, the system also returns back the load to the main
source of supply and stops the generator from running.
The whole system is an electromechanical automated process, comprising of contactors
and different relays of powered by A.C. and D.C. Voltages. The electronic components
such as resistors, diodes and some IC were also used to realize the working of the
project. The two contactors used are to ensure the connection of the load to supply
source, depending on mains or generator. A three-pole relay performs the transfer
function by energizing the mains contactor as situation depends. The set of two single
pole delays used is to achieve a phase changing process, termed the phase changer as
designated on the block diagram.