Abstract:

The guide clearance between the hole of the static iron core and the guide rod is the key parameter affecting the movement of the contact bridge of the direct-acting double-break electrical apparatus. To investigate its influence on the arcing characteristics, multi-body dynamics simulation software is adopted to analyze the motion characteristics of the contact bridge under different guide clearances, a three-dimensional arc magnetohydrodynamics model is established to investigate the influence of the guide clearance on the arcing characteristics of the bridge contact. Through the research on a type of double breakpoint high-power DC relay, it is found that reducing the guide clearance can effectively suppress the unbalanced breaking of the contact bridge and the contact breaking jitter, reduce the breaking speed difference between the two contacts, and significantly reduce the arc energy difference between them. When the clearance is reduced to 0.3 mm, the contact approaches a balanced breaking state, and the arc energy difference between the two sides of the contact is only 0.042 J, which is 86.5% less than that when the clearance is 1.0 mm. Taking both performance and manufacturing requirements into consideration, the guide clearance of 0.3 mm is selected as the optimal solution, which helps to improve the breaking balance and arcing balance of the relay.

Key words: bridge-type contact, guide clearance, unbalanced arcing, dynamics simulation