Design and development of a low cost automatic transfer switch (ATS) with an over-voltage protection.

Abstract

Erratic power supply owing to inability of public power supply utilities to meet the demands of the populace has necessitates the need for an alternative or emergency source of power supply (such as generator set). In this case, transfer switch is usually used to transfer different sources of power to the load. Manual transfer switch involves the use of manpower in operating the generator set and then changing the supply from utility line to generator, when there is power failure, and vice-versa, this often wastes time and sometimes unreliable. Hence, the needs for an automatic transfer switch. The objectives on the design centers on sensing of the primary/main source of power supply when restored, startup the secondary source (generator) when main power fails, shutdown the generator when the main source is power restored as well as automatic transfer of load to the available power source, thereby making the entire process easy and reliable. In order to achieve the objectives, the utility power supply (main source) considered in this the study is single phase power supply and the device it made to operate on a 5KVA single phase (key operated) generator set. The main design was carried out with a low cost solid state electronic component such as; contactor, transformer, relays, Op-amp, 555 timer, voltage regulator, transistors, resistors, capacitors, diodes and so on. The entire work was implemented with hardware, tested working and perfectly functional.