Quasi-analytical Design of a Square Helmholtz Coil with Finite Cross-sectional Area as a Magnetic Flux Density Standard

Sakda Somkun, Thepbodin Borirak-Arawin
Abstract:
This paper describes a design methodology of a square Helmholtz coil with finite cross-sectional area to be used as a magnetic flux density standard up to 50 mT at NIMT. Magnetic field inside the square Helmholtz coil was considered to be assembled from the magnetic fields produced by every pair of square loops, which were analytically derived from the Biot-Savart law. This design technique, based on physical properties of the copper wires, allows the coil resistance to be easily predicted to match the output characteristics of the DC power supply. Temperature rise in the coil and the decrease of the coil constant due to thermal expansion were also taken into account. The calculated magnetic field was found to be closely agreed with finite element modelling (FEM). A design prototype was constructed and results showed good agreements with the numerical calculation.
Keywords:
magnetic flux density, Helmholtz coils, magnetic standard
Download:
IMEKO-TC4-2013-028.pdf
DOI:
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Event details
IMEKO TC:
TC4
Event name:
TC4 Symposium 2013
Title:
19th IMEKO TC4 Symposium Measurements of Electrical Quantities (together with 17th TC4 IWADC Workshop on ADC and DAC Modelling and Testing)
Place:
Barcelona, SPAIN
Time:
18 July 2013 - 19 July 2013