Auto supply switching is basically selection of supply from multiple available power sources automatically by using microcontroller concept that is to check the availability of the source and switching to that available source to ensure uninterrupted power supply to load. In case of the electrical appliance control using automation causes more safety.
Auto supply switching is a prototype for the same which is auto change to other source when main supply fails without human interaction in this system we are designing an embedded circuit to control and ensure auto supply switching. In case all 4 phases are available, then the switching will be in the default phase. Four relays are there to control the switching. As it is not feasible to provide all 4 different sources of supply, one source with alternate switches are provided to get the same function.
In this project we are having 4 switches which we consider as 4 different source of supply. When we press any of the switches it shows the absence of that particular source which is connected to microcontroller as input signals. Here we are using 8051 family microcontroller. The output of microcontroller is given to the ULN2803 this acts as a relay driver. The current phase working is displayed on LCD also.