To provide a thermoelectric cooled power lead which dispenses with a particular cooling means to effectively performs heat dissipation and cooling by itself in the power lead for connecting electrically a super-conductive coil and an electrical source (a first electrical source) for energizing the super-conductive coil.

The power lead includes a thermo-electric cooling element comprising an n-type thermoelectric material connected with a positive electrode of the electrical source and a p-type thermo-electric material connected with a negative electrode thereof. A high-temperature superconductor may be provided between the thermo-electric cooling element and the superconductive coil. Pairs of the n-type thermoelectric material and the p-type thermo-electric material in a plurality of the thermoelectric cooling elements are connected together at the side of the super-conductive coil to be thereby connected with the superconductive coil and the first electrical source 1 and/or a second electrical source 2 are/is connected with the opposite sides via a group of switches, respectively. When the superconductive coil is excited, p-type and n-type thermoelectric materials are connected in parallel with each other and current is fed to the superconductive coil from at least the first electrical source. Otherwise, connections of the group of the switches are changed to connect the plurality of the thermo-electric cooling elements in series and then electric current value of the second electrical source is reduced.

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