Patent ID: 8314677

Claim:
An overcurrent protective wire wound resistor comprising: a high-temperature opening core having: a rod having two opposite ends; a first contact cap mounted on one of the opposite ends of the rod and having: two opposite ends; and a first lead wire mounted thereon, wherein the first lead wire and the rod are respectively mounted on the two opposite ends of the first contact cap; a resistor connection seat mounted on the other of the opposite ends of the rod; a low melting point conductive layer mounted around a periphery of the rod and extending longitudinally to the first contact cap and the resistor connection seat; a high-temperature contractive insulation layer mounted around the low melting point conductive layer, the first contact cap and an end of the first lead wire connected with the first contact cap, wherein a melting point of the low melting point conductive layer is lower than that of the high-temperature contractive insulation layer; a second contact cap corresponding to the first contact cap of the high-temperature opening core and mounted around the high-temperature contractive insulation layer so that the high-temperature contractive insulation layer is sandwiched between the second contact cap and the first contact cap and the second contact cap is electrically insulated from the first contact cap, and having: a second lead wire mounted on the second contact cap; and a through hole formed through the second contact cap to correspond to the first lead wire for the first lead wire to penetrate through the through hole; and a resistance wire mounted around the rod to correspond to the rod and electrically insulated from the low melting point conductive layer by the intervening high-temperature contractive insulation layer therebetween, wherein two ends of the resistance wire are respectively connected to the resistor connection seat and the second contact cap, and a melting point of the resistance wire is higher than that of the low melting point conductive layer.