As its name, an automatic transfer switch ATS could automatically transfer power supply from the primary to the backup, such as a generator or a photovoltaic energy storage system, when the main power fails. And it transfers the backup power to the normal power when it is restored. To protect the electrical device during the power transfer, an automatic transfer switch ATS is made up by two circuit breakers and a control unit.
An automatic transfer switch ATS continuously detects and monitors primary power supply system for voltage level, frequency, phase sequence and imbalance. As long as the parameters is within the acceptable limits, the automatic transfer switch ATS will keep to load connect to the primary power supply. On the contrary, the automatic transfer switch ATS will trigger when loss of power, voltage drop, or frequency deviation is detected. Moreover, the follow fails occurred, the automatic transfer switch ATS will send signal to the backup power supply to start, such as power failure, undervoltage, overvoltage, frequency out of range, and phase loss or reversal.
