Three major factors affecting the lifespan of fuses.max fuse size meaning

　　1. Working environment temperature: Excessive ambient temperature can damage the lifespan of fuses. Slow melting fuses, such as tin ball type, begin to diffuse towards the metal wire when the temperature is about 160 ℃ (150-170 ℃); The temperature at which the melt of a fast melting fuse begins to undergo severe oxidation is approximately 200 ℃ (175-225 ℃). With the oxidation of the fuse from the outside to the inside, multiple diffusion, thermal stress fatigue, etc., the lifespan of the fuse will gradually shorten. Therefore, it is recommended that the delay type fuse fuse should not work above 150 ℃ for a long time, and the fast melting type fuse should not work above 175~225 ℃ for a long time.

　　2. Pulse current: Pulse impact can generate thermal cycling, leading to diffusion, oxidation, thermal stress, and even acceleration of the fuse. The fuse will gradually age with increasing pulse energy and frequency. The impact resistance life of a fuse depends on the percentage of I2t of the pulse to I2t of the fuse itself; Normally, it should be less than 20%, so that the fuse can withstand more than 100000 impacts.

　　3. Contact parts: The pipe clamp that the fuse contacts, as well as the length and cross-sectional area of the connecting wire. The contact resistance between the fuse and the clamp is high, which is detrimental to its lifespan. According to UL standards, the contact resistance between the fuse and the clamp during testing is less than 3m Ω. When the contact resistance is high, the pipe clamp does not dissipate heat but generates heat and transmits it to the fuse.

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