Vacuum Circuit Breaker Technology and Assembly Line
Vacuum circuit breakers are advanced electrical devices that utilize vacuum as the arc-quenching medium, offering high efficiency and reliability. Their core components include the vacuum interrupter, operating mechanism, and secondary circuit. The assembly process involves meticulous steps such as material preparation, enclosure installation, vacuum interrupter fitting, and secondary circuit wiring. After assembly, rigorous testing is conducted, including mechanical characteristic tests, withstand voltage tests, and vacuum degree checks, to ensure the breaker’s performance and safety. Modern assembly lines are highly automated, equipped with PLC control and MES systems for real-time monitoring and data collection, ensuring high production efficiency and product quality. These breakers are known for their small size, long life, and environmental friendliness, making them ideal for modern power systems.
I. Overview of Vacuum Circuit Breaker
A vacuum circuit breaker (VCB) is a type of switching device that extinguishes arcs in a vacuum environment. The core principle is to use a high-vacuum environment as the arc-quenching medium. When the circuit is interrupted, an arc is generated as the contacts separate. Since there is no gas medium in the vacuum, the arc cannot be sustained and is quickly extinguished. This arc-quenching method is highly efficient and rapid, capable of interrupting high currents in a short time and reducing the risk of power system failures.
The main components of a vacuum circuit breaker include the vacuum interrupter, the enclosure, the operating mechanism, and the secondary circuit. The vacuum interrupter is the core component, typically consisting of a high-vacuum glass or ceramic enclosure and high-temperature-resistant contact materials (such as copper-chromium alloy). The enclosure supports and protects the internal components, while the operating mechanism controls the opening and closing actions of the contacts.
Vacuum circuit breakers are known for their small size, light weight, long operating life, and ease of maintenance. Since no oil or gas is required for arc quenching, they are more environmentally friendly and suitable for applications with frequent operations.
II. Vacuum Circuit Breaker Structure Table
| No. | Component Name | Description |
|---|---|---|
| 1 | Insulating Cylinder | Used for insulation and support of internal components |
| 2 | Upper Bracket | Secures the upper terminal and other components |
| 3 | Upper Terminal | Connects to the upper part of the external circuit |
| 4 | Vacuum Interrupter | Core component for closing and breaking the circuit, and extinguishing arcs |
| 5 | Flexible Connection | Provides electrical connection while allowing some movement |
| 6 | Lower Bracket | Secures the lower terminal and other components |
| 7 | Lower Terminal | Connects to the lower part of the external circuit |
| 8 | Disc Spring | Provides operating force or holding force |
| 9 | Insulating Rod | Transmits operating force, connecting the operating mechanism to the interrupter |
| 10 | Four-Bar Linkage | Transmits the movement of the operating mechanism to the interrupter, enabling closing and opening operations |
| 11 | Circuit Breaker Enclosure | Protects internal components from external interference and contamination |
| 12 | Opening Spring | Provides the force for the opening operation |
| 13 | Opening Electromagnet | Electromagnetic device for controlling the opening operation |
| 14 | Closing Cam | Mechanical component for controlling the closing operation |
III. Vacuum Circuit Breaker Process Flow Table
| Process Name | Main Content |
|---|---|
| Main Shaft Assembly | Install the main shaft components and buffers into the housing, ensuring correct assembly before moving to the next process |
| Mechanism Assembly | Assemble the closing and opening operating mechanisms, and secure them after pre-assembly |
| Housing and Spring Assembly | Complete the assembly of closing and opening springs |
| Phase Column Pre-assembly | Perform pre-assembly of internal flexible connections, double-ended rods, and insulators in the phase column |
| Phase Column Assembly | Install the pre-assembled phase column components onto the housing |
| Base Assembly | Install the base and related components |
| Contact Arm Assembly | Install the contact arm and related components |
| Secondary Circuit Assembly | Complete the wiring and layout of the auxiliary control circuit |
| Mechanical Run-in | Perform mechanical run-in on the assembled circuit breaker to ensure coordinated actions |
| Characteristic Testing | Conduct mechanical characteristic testing, withstand voltage testing, and circuit resistance testing |
| Final Inspection | Perform a comprehensive inspection of the product to ensure quality compliance |
| Offline and Warehousing | Qualified products are taken offline and stored in the warehouse |
IV. Vacuum Circuit Breaker Assembly and Testing Table
| Test Item | Test Content |
|---|---|
| Appearance Inspection | Inspect the appearance of the circuit breaker to ensure there are no defects or damage |
| Mechanical Characteristic Testing | Test parameters such as contact gap, contact travel, synchronicity, and bounce |
| Withstand Voltage Testing | Conduct AC withstand voltage and impulse withstand voltage tests |
| Circuit Resistance Testing | Measure the connection quality of the conductive circuit |
| Vacuum Degree Testing | Use a vacuum tester for qualitative testing |
| Operating Characteristic Testing | Test the closing and opening speeds |
| Low-Voltage Opening and Closing Test | Ensure the circuit breaker can reliably operate at low voltage |
| Continuous No-Load Operation Test | Verify the stability of the equipment during continuous operation |
V. Vacuum Circuit Breaker Assembly Line
A. Assembly Process
- Material Preparation and Verification
Check the materials according to the assembly flow card to ensure that all components are present and meet the requirements. - Enclosure and Auxiliary Unit Installation
Assemble the outer frame and enclosure to support and protect the internal components. - Closing and Opening Unit Assembly
Install the closing and opening units to ensure coordinated actions. - Vacuum Interrupter Installation
Install the vacuum interrupter in place and seal it. - Secondary Circuit Wiring
Complete the wiring and layout of the auxiliary control circuit.
B. Testing Process
- Appearance Inspection
Inspect the assembled circuit breaker to ensure there are no defects. - Mechanical Characteristic Testing
Test parameters such as contact gap, contact travel, synchronicity, and bounce. - Withstand Voltage Testing
Conduct AC withstand voltage and impulse withstand voltage tests. - Circuit Resistance Testing
Measure the connection quality of the conductive circuit. - Vacuum Degree Testing
Use a vacuum tester for qualitative testing. - Operating Characteristic Testing
Test the closing and opening speeds. - Low-Voltage Opening and Closing Test
Ensure the circuit breaker can reliably operate at low voltage. - Continuous No-Load Operation Test
Verify the stability of the equipment during continuous operation.
C. Automated Assembly Line
Modern vacuum circuit breaker assembly lines typically feature highly automated designs, including modular design, automated assembly, online inspection, and intelligent logistics systems. Through PLC control and MES (Manufacturing Execution System), the production process is monitored in real-time and data is collected to improve production efficiency and product quality.
D. Quality Assurance
The assembly line is equipped with automatic withstand voltage equipment and dedicated internal pressure measurement processes to ensure the reliability and consistency of the products. In addition, the assembly process is conducted in a clean room environment to ensure the cleanliness of the products.
Through the above structural design, process flow, and testing procedures, vacuum circuit breakers can be produced efficiently and with high quality, meeting the requirements of modern power systems for reliability and safety.