| 摘要 |
<p>A series-connected, skin-current heating pipe circuit includes a first ferromagnetic pipe; a first insulated wire extending along and inside the first pipe; a first AC source connected to one end of each of the first pipe and first wire; and an impedance element, such as a resistor, capacitor or reactor connected between the other end of each of first pipe and first wire. A current trouble detector is provided in either line connecting the first AC source to the one end of the first pipe or the one end of the first insulated wire to detect a current trouble due to an insulation problem at any point of the first insulated wire. The circuit may include a second AC source, a second ferromagnetic pipe and a second insulated wire extending along and through the second pipe arranged so that the one end of the first ferromagnetic pipe is connected via the second ferromagnetic pipe, second insulated wire and second AC source to the first AC source and a current trouble detector is connected between a line connecting the first and second ferromagnetic pipes and a wire connecting the first and second AC sources to detect a current flowing therein. An impedance element in the form of a resistor, capacitor or reactor may be connected in circuit between the second ferromagnetic pipe and the second insulated wire.</p> |
