Key factors affecting the operating characteristics of drop-out fuses

Melt geometry parameters
drop out fuse When the ratio of melt thickness 8 to width b (8/b) is controlled at 0.3-0.6, the best thermal stress distribution can be obtained. The spiral melt design increases the effective heat dissipation area by 40% and reduces the let-through energy to below 50kA2s.
Arc extinguishing medium characteristics
The quartz sand particle size grading adopts a mixed scheme of 0.2-0.5mm accounting for 60% and 0.5-1mm accounting for 40%. When the stacking density reaches 1.6g/cm, the best arc extinguishing channel can be formed. Adding 3%-5% Al₂O₃ can increase the medium recovery strength by 30%.
Gas dynamic effect
The CO2, H₂O and other gases generated by the decomposition of the gas-producing material form a longitudinal arc blowing airflow at a pressure of 3-5MPa. When the flow rate reaches 120-150m/s, the arc reignition can be effectively suppressed, and the medium
strength recovery rate>1kV/μS.
Environmental adaptability
In a low-temperature environment of -25℃, the fracture toughness of the melt decreases by 15%, and the low-temperature brittleness needs to be compensated by adjusting the tin content (adding 0.5%-1.2%). High humidity environment (RH>85%)
The inner wall of the melting tube is treated with silanization to prevent surface flashover.