This paper proposes a new method for noncontact measurement of the dc current. This device utilizes the skin effect of an ac current flowing in a ferromagnetic pipe with an amorphous-tape wound structure. The dc current controls the skin depth of the ac current. This dc-current transformer (CT) has no winding and outputs the difference between the terminal voltage of the pipe and the induced voltage in a one-turn coil. The ac current does not affect the dc line because of axis symmetry. A linear relation between the output and dc current is obtained when an appropriate ac drive frequency is selected. Improvement of gain can be attained by reducing the diameter. It is clarified that the magnetic pipe is applicable for a dc-CT with a small size.
ASJC Scopus subject areas
- Physics and Astronomy(all)