公开(公告)号：US4219857A

公开(公告)日：1980-08-26

申请号：US863501

申请日：1977-12-22

申请人： Eythor M. Haraldsson ,  LeRoy J. Herbst

发明人： Eythor M. Haraldsson ,  LeRoy J. Herbst

IPC分类号： H02H5/04 ,  H05B3/48 ,  H02H3/16

CPC分类号： H02H5/04 ,  H02H5/043 ,  H05B3/48

摘要： In one embodiment, a sheathed electrical resistance heating unit is operated from a 120 volt unbalanced-to-ground household power line. The heating unit sheath is grounded. In order to interrupt a fault between the actual resistance heating element and the outer sheath of the heating unit, regardless of where along the length of the heating unit the fault occurs, a fuse is connected in series with the "hot" side of the power line, and, by means of at least one unidirectional current conducting device, the two terminals of the heating element are effectively connected, through the fuse, to the "hot" side of the power line during alternate AC half-cycles.

摘要翻译： 在一个实施例中，护套电阻加热单元由120伏不平衡对地家庭电力线操作。 加热单元护套接地。 为了中断加热单元的实际电阻加热元件与外护套之间的故障，不管沿着加热单元长度的哪里发生故障，保险丝与电源的“热”侧串联连接 并且通过至少一个单向电流传导装置，在交替的半周期期间，加热元件的两个端子通过熔丝被有效地连接到电力线的“热”侧。