The Auto Transfer Transformer (ATS-US) controls the switch of the contactors to provide power to the critical load stated as EPS Emergency Power Supply load in both grid-tied and off-grid conditions. There is a contactor in ATS-US to provide user a simple connection.
ATS-US is operating with PCS inverter for the purpose of providing the split phase power when grid accidentally or unexpectedly goes off. This approach allows the home critical continuously to be supplied.