Q1-63 automatic transfer switch (ATS), suitable for AC 50Hz or 60Hz, rated working voltage 400V, rated working power 63A and below dual-circuit power supply system. The two power supplies can be selectively switched as needed. It has short circuit, overload, loss of voltage protection functions, and also has the function of outputting closing signals. It is especially suitable for the installation and use of lighting circuits in office buildings, shopping malls, banks, stations, hospitals, and high-rise buildings.