Abstract:

To enhance the arc-extinguishing performance of small DC circuit breakers,the principles related to DC arcs are reviewed,and three types of arc splitter plates with different lengths are designed.Modeling and simulation are carried out on the arc chamber of a specific small DC circuit breaker before and after improvement.The simulation results show that the arc-extinguishing performance of the improved arc chamber is better than that of the original one.Under different inlet velocities,the higher the inlet velocity,the better the arc-extinguishing performance.Three types of test prototypes are manufactured,and electrical endurance tests are conducted in accordance with GB/T 14048.2—2020 Low-Voltage Switchgear and Controlgear—Part 2: Circuit breakers.The make-break time of each opening and closing operation is recorded and averaged.The test results show that the average make-break time of the prototype with the improved arc chamber is shorter,and the average make-break time of the prototype with gas-generating material placed above the moving and stationary contacts is also shorter.The consistency between the simulation and test results is verified,which provides a reference for product performance optimization.

Key words: DC circuit breaker, arc extinguishing chambers before and after improvement, gas-generating materials, arc extinguishing performance