Comparison of calibration systems for magnetic field measurement equipment

The current ANSI/IEEE standard specifies two possible methods for magnetic meter calibration: A single square loop or a round Helmholtz coil. However it (a) does not specify the size of the coil and (b) does not provide a comparison of the field uniformities between the two suggested systems. In this paper, the z-directed magnetic field equations for four calibration system designs, the single round loop, the round Helmholtz coil, the single square loop, and the square Helmholtz coil are derived and presented. For the square systems, this paper presents the derivations for the first time in the open literature. Also, this paper is the first to present a comparison of the field uniformities of the four systems.