DESIGN AND CONSTRUCTION OF AN AUTOMATIC POWER CHANGEOVER SWITCH

Power failure or outage in general hinders development of public and private sectors in a country as most industrial and commercial processes are dependent on electrical power. This limit the development of industries. Also there are processes that require constant and steady power supply; that is, cannot be interrupted because of their importance. For instance the control tower in an airport, internet banking operation telecommunication base stations and lots more. This paper presents the design and construction of an automatic power changeover switch that switches power supply from public power supply to generator once there is public power supply outage and it does this automatically. The methods employed in designing the automatic change over switch involve the use of electromechanical type relays, contactors, voltage monitoring relays and delay timer relays as main components of the system. The output of the power supply unit which powers the relays was tested by making the relays to change over immediately the power varies with a generator and public supply source. A single electric bulb was used for testing, when the utility supply is ON and the source of the generator OFF the bulb which is the load lights. When the utility supply is OFF and the generator switch ON, the load which is the bulb lights; thus confirming the normal open and close of the relays.