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A Fixed Type Indoor Circuit Breaker is a permanently installed medium voltage switching device designed for safe power distribution, fault protection, and reliable circuit control inside indoor switchgear systems. Compared with withdrawable circuit breakers, the fixed mounting structure eliminates racking mechanisms, providing higher mechanical stability, simpler installation, and reduced maintenance requirements.
Our fixed mounted vacuum circuit breakers are engineered for industrial plants, utility substations, commercial facilities, renewable energy projects, and medium voltage distribution networks. By combining advanced vacuum interruption technology, durable insulation systems, and proven operating mechanisms, these breakers provide dependable performance for applications requiring continuous power availability.
Unlike draw-out type breakers that require movable contacts and a withdrawal mechanism, fixed type indoor circuit breakers are directly installed inside the switchgear compartment. This simplified structure reduces mechanical components, minimizes potential failure points, and provides excellent resistance against vibration and environmental stress.
For projects where frequent breaker replacement is not required, a fixed installation offers an economical and reliable alternative while maintaining the same high-level protection performance as advanced medium voltage vacuum circuit breakers.
The breaker structure combines vacuum interrupters, insulated poles, conductive terminals, and spring operating mechanisms into a compact protection unit. Each main component is selected to maintain stable performance during normal operation as well as short-circuit conditions.
The operating mechanism uses a stored-energy spring design to achieve consistent opening and closing speed, ensuring dependable fault interruption regardless of operating frequency. Before delivery, every unit undergoes mechanical operation testing, insulation testing, and electrical performance verification to ensure compliance with international standards.
| Parameter | Specification |
|---|---|
| Product Type | Fixed Mounted Indoor Vacuum Circuit Breaker |
| Rated Voltage | 12kV / 17.5kV / 24kV |
| Rated Current | 630A / 1250A / 2000A / 3150A |
| Rated Frequency | 50Hz / 60Hz |
| Rated Short Circuit Breaking Current | 25kA / 31.5kA / 40kA |
| Short-Time Withstand Current | Up to 40kA (3 seconds) |
| Peak Withstand Current | 63kA / 80kA / 100kA |
| Power Frequency Withstand Voltage | 28kV / 38kV / 50kV |
| Lightning Impulse Withstand Voltage | 75kV / 95kV / 125kV |
| Operating Mechanism | Spring stored-energy mechanism |
| Mechanical Endurance | 10,000 operations |
| Electrical Endurance | Up to 30 fault interruptions at rated short circuit current |
| Auxiliary Supply Voltage | 110V DC / 220V DC / 110V AC / 240V AC |
| Operating Temperature | -5°C to +40°C (optional -25°C) |
| Relative Humidity | ≤95% non-condensing |
| Installation Altitude | ≤1000m above sea level |
| Applicable Standards | IEC 62271-100, GB/DL equivalent standards |
Fixed type indoor circuit breakers are widely used in medium voltage power systems where stable operation, compact installation, and reliable protection are required.
As a professional medium voltage switchgear manufacturer, we provide customized fixed type indoor circuit breaker solutions according to different project requirements, including rated voltage selection, current capacity, control voltage configuration, protection accessories, and switchgear integration requirements.
Our production process includes precision component machining, vacuum interrupter inspection, insulation performance testing, mechanical endurance verification, and final functional testing before shipment. This ensures every breaker delivered to global customers meets strict reliability requirements for long-term operation.
Q1: What is a fixed type indoor circuit breaker?
A fixed type indoor circuit breaker is a permanently installed medium voltage breaker used for electrical protection and switching inside indoor switchgear. It does not include a withdrawable mechanism, making the structure simpler and more compact.
Q2: What is the difference between fixed type and draw-out circuit breakers?
Fixed breakers provide a simpler and more economical structure, while draw-out breakers allow easier replacement and maintenance through a movable mechanism. Fixed designs are preferred for installations where continuous operation and compact construction are priorities.
Q3: Can the breaker be customized for different power systems?
Yes. Rated voltage, current capacity, control voltage, accessories, and switchgear integration requirements can be customized according to project specifications.
