Higher harmonic suppressor element and DC power supply unit using the same

A DC power supply unit comprising:

• a voltage selection switch for selecting either one of a first AC voltage and a second AC voltage which is twice as high as said first AC voltage, wherein each voltage is supplied from an AC power supply;
• a rectifying/smoothing circuit for rectifying and smoothing said first AC voltage by the double voltage rectification method if said first AC voltage is selected by said voltage selection switch and, if said second AC voltage is selected by said voltage selection switch, rectifying and smoothing said second AC voltage by the equi voltage rectification method;
• and
• the higher harmonic suppressor element which is interposed between said AC power supply and said rectifying/smoothing circuit only when said second AC voltage is selected by said voltage selection switch, wherein the higher harmonic suppressor element including a higher harmonic coil for suppressing a higher harmonic and a thermal fuse which is connected in series with said higher harmonic coil and also which is melted down by heat generated by said higher harmonic coil, said DC power supply unit not comprising an electrical superconductor.