TITLE:
Toroidal Coil in Measuring Alternating Current at a Distance
AUTHORS:
Seppo Mäkinen
KEYWORDS:
Rogowski Coil, Current Transformer, Toroidal Coil, Electromagnetic Induction
JOURNAL NAME:
Journal of Electromagnetic Analysis and Applications,
Vol.6 No.12,
October
13,
2014
ABSTRACT: This
article discusses the use of a toroidal coil in measuring alternating current
from a straight current-carrying wire passing perpendicularly through the coil.
The sinusoidally oscillating current generates a sinusoidally oscillating
magnetic field in its vicinity. This, in turn, induces a sinusoidally
oscillating emf in the toroid. This (measured) emf can be used in order to
calculate the magnitude of the electric current in the wire. The use of such
technique might be sensitive to the location of the point at which the wire
passes through the toroid. If the location is not known very precisely, this
might cause errors in the value of the calculated current. We wanted to study
if the result does not depend on the location of the wire at all, as is usually
stated, or not. The study was done by deriving a single analytical formula for
finding out the calculated current with the wire passing through any given
point inside the toroid. This formula was then solved at more than 2300 points
inside a toroid to see if the location of the wire affects the result or not.