DESIGN AND CONSTRUCTION OF AN AUTOMATIC SINGLE PHASE CHANGEOVER SWITCH

DESIGN AND CONSTRUCTION OF AN AUTOMATIC SINGLE PHASE CHANGEOVER SWITCH

ABSTRACT

Considering the epileptic power supply in Nigeria and other developing countries today, a high demand of an alternative service is required. A single phase automatic change over switch from the public mains supply to the auxiliary supplies (single phase ac generator) and vice-versa has been developed. The design was realized using major components like a step down transformer (220V-12V dc), atmega8 microcontroller, rectifiers, voltage regulators, 555 timers, relays,  circuit breaker and others like resistors, diodes, and capacitors. The device automatically switches from public mains to an auxiliary whenever there is an outage in the public mains. This device also detects the public main power supply when available and switches from auxiliary power supply to the mains with a delay period of 4 seconds in starting and switching off the generator. The device has been constructed successfully, and it demonstrated a tendency to automatically switch from mains to the auxiliary source and vice-versa without human interception.