AT30 industrial PC-level automatic transfer switch, equipped with high-performance H-type controller, can be applied to the standby system of two mains and mains – generator. AT30 adopts anti-idle secondary terminal design which is safe and convenient to introduce the power supply from the main circuit. H-type controller can be used to monitor the common power supply’s loss of voltage, lack of phase, under voltage, overvoltage, under frequency, overfrequency, phase sequence and other parameters, while monitoring wether the standby power supply is normal. When the main power circuit has voltage loss or power failure, undervoltage, overvoltage, over frequency, under frequency, phase break, phase sequence and other faults, the switch will be automatically put into the standby power circuit (can be adjusted as delayed); When the power supply of the main power loop returns to normal, the switch will automatically throw the load back to the main power loop (can be adjusted as delayed).