| 摘要 |
PURPOSE: To provide a corrosion protection apparatus of the metal structure capable of effectively preventing corrosion from forming on a metal structure that is a corrosion protection object as preventing overprotection by properly diversifying a protection current capacity supplied to the metal structure side correspondingly to change of corrosion environment, thereby supplying the optimum current capacity. CONSTITUTION: The corrosion protection apparatus of metal structure comprises a cathode of input power source connected to the metal structure (1), an anode main body attached to a surface of the metal structure, and an anode current control part for controlling an anode current supplied to the metal structure from the anode main body, wherein the anode current control part comprises the first resistance (R1) for connecting an anode of input power source supplied through first conductor line (W1) to the anode main body, second resistance and first transistor (11) for connecting the anode of input power source along with the first resistance to the anode main body in a row, the third resistance (R3) and the second transistor (12) for connecting the anode of input power source to the anode main body in a row, and the fourth resistance (R4) connected onto second conductor line (W2) for connecting the cathode of input power source to the metal structure, wherein the anode current control part is controlled such that an anode current is decreased to prevent overprotection by passing an electric current inputted into the anode main body through the first resistance side only in case that an anode electric potential is a preset value or more, and the anode current is supplied to the anode having a relatively high anode electric potential by passing through the second resistance only in case that the anode electric potential is a preset value or less.
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