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Indoor High Voltage Vacuum Circuit Breaker
ZN28-12K
1.General Description
ZN28-12K fixed type indoor MV vacuum breaker is used for many kinds of switchgears
like XGN2-t2 (Z). It is widely used for 12kV voltage systems which is accordance with GB1984-2003 standards.
Structural characteristics:
1.This vacuum circuit breaker adopts air insulation.lt can meet air distance and creepage under normal run condition.
2.The operating mechanism can use CD17 or CT19 type mechanism,the outlet curve has good adaptation for vacuum interrupters.lt has high reliable with characteristics of long life and easy maintenance.
3.Convenient for matching with switchgear;convenient and reliable operation;compulsive mechanical interlock way is adopted;meet “Five Prevention” function.
2.Applying conditions:
Ambient temperature;-10℃----+40℃
Relative humidity:daily average ≤95%,monthly average ≤90%
Seismic intensity ：≤8
Saturated vapor pressure：daily average ≤2.2kPa，monthly average≤1.8kPa；
Altitude：≤1000m；（Not including special requirement）
Service environment：should be avoided fire, explosion risk, serious pollution, chemical corrosion and violent vibration
3.Technical specification：
No. | Item | Unit | Data | |||||
1 | Rated voltage | kV | 12 | |||||
2 | Rated frequency | Hz | 50/60 | |||||
3 | Rated power frequency withstand voltage/1min | kV | 42 | |||||
4 | Rated lighting impulse withstand voltage | kV | 75 | |||||
5 | Rated current | A | 630 | 1250 | 1600 | 2000 | 2500 | 3150 |
6 | Rated short circuit breaking current Rated short time withstand current(4s) | kA | 20 | |||||
25 | 25 | |||||||
31.5 | 31.5 | 31.5 | 31.5 | |||||
40 | 40 | 40 | 40 | |||||
7 | Rated short circuit making current(peak) Rated withstand current(peak) | kA | 50 | |||||
63 | 63 | |||||||
80 | 80 | 80 | 80 | 80 | ||||
100 | 100 | 100 | 100 | 100 | ||||
8 | Mechanical life | Times | 10000 | |||||
9 | Rated duration of short circuit | s | 4 | |||||
10 | Rated operating sequence | O-0.3s-CO-180s-CO | ||||||
O-180s-CO-180s-CO(40kA以上） | ||||||||
11 | Rated short circuit breaking times | Times | 30 | |||||
12* | Rated single capacitor bank breaking current | A | 400 | |||||
13* | Rated back to back capacitor bank breaking current | A | 400 | |||||
14 | Clearance between open contacts | mm | 11 ± 1 | |||||
15 | Over-travel of contact | mm | 4 ± 1 | |||||
16 | Opening &closing simultaneity of 3 phase contact | ms | ≤ 2 | |||||
17 | Bounce time of contact closed | ms | ≤ 2 | |||||
18 | Closing time | ms | 50~100 | |||||
19 | Opening time | ms | 20~60 | |||||
20 | Average closing speed | ms | 0.6 ± 0.2 | |||||
21 | Average opening speed | m/s | 1.1 ± 0.2 | |||||
22 | Max DC component | 50% | ||||||
4.Overall drawing
Secondary connection diagram
Circuit breaker series 
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