YCW1 1000 series intelligent air circuit breakers (hereinafter called ACB) are applied for the network circuit of AC 50Hz,rated voltage 400V,690V and rated current up to 1000A. Mainly used for distributing energy and protecting the circuit and power supply device against short-circuit, undervoltage, single-phase ground fault etc. The ACB have intelligent protection function and the key parts adopt intelligent release. The release can make the accurate selective protection, which can avoid cutting off the power and improve the reliability of power supply. The products confirm with IEC60947-2, GB14048.2.