A. Eneral introduction
Type VS1 indoor AC high-voltage vacuum breaker is an integral totally-enclosed type high-voltage switching plant with small volume and compact structure. It is suitable for three-phase AC electric power system for protecting and controlling the circuit and electrical equipments, where the normal voltage and mormal frequency arc respectively 12KV and 50Hz(60Hz). It also can be used for the areas where the power network is operated frequently. The products comply with the regulations of relevant standards such as GB/T1984, JB3855 and DL403.
B. Ambient condition for use
A. Ambient air temperature: Upper limit: +40, lower limit: -25
B. Height above sea level: Not more than 1000m, If it is used in the system whose voltage voltage is 7.2KV, the height above sea level can be 3000m.
C. Relaive humidity: Daily average value is less than 95%. Monthly average value is less than 90%
D. Saturated vapor pressure: Daily average value is less than 2.2kpa.
E. It is installed at the areas without severe vibration. Seismic intensity is not more than 8.
F. There is no corrosive or combustible gas in the air. The environment should be dry and clean.

C. Main feature
A. Integral structure
As for the breaker, the switch body (main circuit) and operational device is located in the same shell, which make them integral to effectively reduce the volume of switch and to make the structure more compact.

B. Seal installation in the arc extinguish chamber
Three-stage vacuum arc extinguish chambers are installed in the insulating high-strength ageing-resistant epoxy resin tube made by vacuum pouring, which not only strengthens the internal insulating performance, but also makes arc extinguish chambers not to suffer from the invasion of external dust and dirtiness and the damage caused by external mechanical force

C. High-performance vacuum arc extinguishing
Vacuum is used as arc extinguishing medium in the breaker. When electric arc is burning in vacuum, some longitudinal magnetic field is produced between static contact and dynamic contact, which mades vacuum electric arc to diffuse, equably distribute on the contact surface and burn with lower arc voltage, When the current is naturally through zero, the residual ion and metal steam quickly combine and agglomerate on the contact surface and screen cover in an ultrashort time. The medium intensity between the contact fractures is quickly recovered. Then the electric arc is extinguished. Therefore, the breaker has strong and reliable opening and closing capacity.

D. Good mechanical performance
The operational structure of the breaker has enough intensity and rigidity. Its mechanical efficiency is high and stability is good, too. Tripping parts, stored-energy parts, drive parts and buffer parts are respectively installed in five places in the same shell. The distribution is simple and clear, the entirety is strong an action is reliable. Manual or electrically-driven operations are OK.

E. Flexible and various installation modes
The installation modes of the breaker in switch tank can be fixed, retractable with hand buggy and be used by installing on the frame according to different customers' requirements.