Thermal links are also called temperature fuses. When electronic products overheat, they cut off the circuit to avoid fire.
The main contact in the thermal fuse is called the star contact, which is mainly made of silver-based electrical contact material. The melting material of the alloy thermal fuse is a low-temperature alloy. When the temperature around the fuse rises to its operating temperature, the alloy will melt and shrink into a ball with the help of surface tension and special resin, attached to the ends of the two pins, thereby permanently cutting off the circuit.
The electrical contact material used as a star contact has the following requirements:
(1) Temperature resistance. It will not soften or deform during continuous operation below the operating temperature.
(2) Low and stable resistance. During continuous power-on, the star contact will not shrink and cut off the circuit before reaching the operating temperature due to the heat generated by the star contact itself.
(3) High resistance to static welding.
(4) Appropriate hardness.
(5) Appropriate resistance to arc burns and dynamic welding.
(6) Good plasticity and elasticity, and will not break during production, assembly, and use.
At present, the most widely used materials are AgCu alloy, AgCuO and AgCuONiO, etc. Among them, AgCu alloy mainly includes AgCu(1) and AgCu(15), AgCuO mainly includes AgCuO(12) and AgCuO(15), and AgCuONiO mainly includes AgCuO(5)NiO(0.6).
Post time: Jun-17-2024