| 摘要 |
A plug-in line protector for a communications circuit provides protection for over voltage and over current conditions of the line. A cup and slug module containing carbon blocks provides an air gap for grounding high voltage transients. For an over current condition, a solder pellet melts causing the cup and slug to engage due to spring pressure and ground the line through a grounding strip. The grounding strip has plastic insulation bonded to a portion thereof and interposed between the line and ground. In an over current condition heat from one of the carbon blocks is transferred through the cup to the metalic strip. This heat may cause the plastic to melt to provide a back-up or secondary low resistance path to ground. The protector may also have a resettable over current responsive mechanism in the form of a heat coil in the line. When the heat coil breaks, a printed circuit board, on which the heat coil is mounted, is moved by a volute spring. In over voltage and in over current conditions, the volute spring conducts current from the printed circuit board to the slug and cup and to ground.
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