Within ZN28A-12 series indoor high voltage vacuum circuit breaker (within ZN28-12 integrated indoor high voltage vacuum circuit breaker) is a three-phase AC 50Hz high voltage vacuum circuit breaker price, rated voltage of 12kV indoor high voltage switchgear circuit breakers, mainly used for fixed switching devices, or replace the old switch device is less oil circuit breaker vacuum circuit breaker factory outlets, also mounted on the protection and control elements withdrawable switchgear, and for frequent operation place. Products meet GB1984 "AC high voltage circuit breakers", JB3855 "AC high voltage vacuum circuit breakers 3.6-40.5kV house" standards and DL / T403 "within 12-40.5kV indoor high voltage vacuum circuit breaker order technical conditions" requirement. Vacuum circuit breaker works with other circuit breakers different compared to the arc medium fills the vacuum does not exist conductive medium, the arc extinguished quickly, so little movement spacing between the contacts of the circuit breaker. The circuit breaker is generally used for relatively low voltage auxiliary power configuration! With the rapid development of power systems, 10KV vacuum circuit breakers have been produced and used in large quantities in China. For maintenance personnel, to improve understanding of the vacuum circuit breaker, strengthen maintenance, making it safe to run, it has become a pressing issue. In this paper, ZW27 - 12 as an example, a brief description of the principles and maintenance of vacuum circuit breakers. Vacuum circuit breaker factory direct _ _ Xi Guangzhou breaker provided by the Xi'an high Huayi power plant. Xian Huayi Electric Power Equipment Factory (www.xahy.com) strong, credible, in the Xi'an high-voltage circuit breakers and other industries has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Huayi electricity into the brilliant and you work for a better future!