The automatic transfer switch is commonly used as the mediator between the service main and the Standby generator. The main function of the Automatic transfer switch is to connect the Standby generator to the building at the time of power outage.

It is a motor operated system where the 12 V dc geared motor do the job. There are three contacts available for each of the three phases and for neutral. Normally the electricity from the service main will be connected to the building, at the time of power outage, the intelligent control system switches the contacts from service points to the generator points, then switch on the standby generator automatically.

When the service main is live, it will switch off the generator after a predetermined interval of time and move the contact to connect the service main with the building. The system is also provided with a generator protection algorithm.