Overview
ZN73-12 series indoor handcart-type high-voltage vacuum circuit breaker is an indoor switchgear with three-phase AC 50Hz and rated voltage of 12kV. It can be used for control and protection of industrial and mining enterprises, power plants, substations, and electrical facilities, and is suitable for in frequently operated places. The operating mechanism is integrated with the circuit breaker body, and the design can be used as a fixed installation unit, or it can be equipped with a special propulsion mechanism to form a handcart unit. The main circuit part can use the integral solid-sealed pole to realize the miniaturization, high reliability and maintenance-free of the circuit breaker.Normal Use Conditions
◆Ambient temperature: not higher than 40℃, not lower than -10℃ (storage and transportation at -30℃ are allowed). ◆Altitude: no more than 1000m. (If the altitude needs to be increased, the rated insulation level will be increased accordingly) ◆Relative humidity: the daily average is not more than 95%, the daily average of saturated vapor pressure is MPa, and the monthly average is not more than 1.8×10. ◆Earthquake intensity: no more than 8. ◆A place without fire, explosion, serious pollution, chemical corrosion and severe vibration.The Main Technical Parameters
| Serial number | Name | Units | Data | |||
| 1 | Rated voltage | kV | 12 | |||
| 2 | Maximum working voltage | kV | 12 | |||
| 3 | Rated current | A | 630 1250 | 630 1250 1600 2000 2500 3150 | 1250 1600 2000 2500 3150 4000 | |
| 4 | Rated short-circuit breaking current (rated thermally stable current - RMS) | kA | 20/25 | 31.5 | 40 | |
| 5 | Rated short-circuit making current (peak value) | kA | 50/63 | 80 | 100 | |
| 6 | Rated peak withstand current (rated dynamic stable current - peak value) | kA | 50/63 | 80 | 100 | |
| 7 | 4S rated short-circuit withstand current | kA | 20/25 | 31.5 | 40 | |
| 8 | Rated insulation level | Working withstand voltage (before and after rated breaking) 1 min power frequency withstand voltage | kv | Ground 42 (fracture 48) | ||
| Impulse withstand voltage (before and after rated breaking) Rated lightning impulse withstand voltage peak value | Ground 75 (fracture 85) | |||||
| 9 | Rated thermal stabilization time | s | 4 | |||
| 10 | Nominal Operation Sequence | Score - 0.3S - Combined - 180S - Combined | ||||
| 11 | Mechanical life | times | 20000 | |||
| 12 | Rated short-circuit breaking current breaking times | times | 50 | |||
| 13 | Operating mechanism rated closing voltage (DC) | v | AC . DC 110，220 | |||
| 14 | Operating mechanism rated opening voltage (DC) | v | AC . DC 110，220 | |||
| 15 | Contact Spacing | mm | 11±1 | |||
| 16 | Overtravel (contact spring compression length) | mm | 3.5±0.5 | |||
| 17 | Three-phase opening and closing bounce time | ms | ≤2 | |||
| 18 | Contact closing bounce time | ms | ≤2 | |||
| 19 | Average opening speed | m/s | 0.9~1.2 | |||
| Average closing speed | m/s | 0.5~0.8 | ||||
| 20 | Opening time | at the highest operating voltage | s | ≤0.05 | ||
| 21 | at minimum operating voltage | ≤0.08 | ||||
| 22 | Closing time | s | 0.1 | |||
| 23 | Main circuit resistance of each phase | υ Ω | 630≤50 1250≤45 | |||
| 24 | The dynamic and static contacts allow the accumulated thickness of wear | mm | 3 | |||