Fuse resistor
Xiamen SET electronics Co.,Ltd
◎SET developed a compact structure innovatively which integrated thermal cutoff and wire wound resistor in a tubular case. It has the same size and shape as a resistor without PCB redesign, offer higher security and wave-soldering.
◎Normal WWR is assembled by using alloy wire having a high melting point, it can be broken quickly only suffering more than 4X~5X rated current. While there is only a small fault current through its body, it would heat continuously and reach a rather high temperature up to 300-500℃. It will damage other components and plastic around.
◎The popular solution to this problem is to connect a thermal fuse with the WWR in series closely. Thermal fuse will be triggered by WWR's abnormal over temperature. But this is not a best solution. Because thermal fuse responds slowly due to low heat transfer efficiency. So the risk of over temperature still exists. Another shortcoming is not wave soldering, occupy more spaces on the PCB.
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