• M.J. Hagmann
  NewPath, Salt Lake City, Utah

We have derived algebraic expressions for the open-circuit voltage that is induced on a Rogowski coil, having imperfectly spaced turns, by a time-dependent current which passes through the aperture of the coil. The derivation of these expressions requires that the layer of the winding is thin, the number of turns is large, and the cross-section of the winding is uninform and rectangular. Examples are given in which these expressions are applied to determine the effects of the gap between the ends of the coil, as well as other irregularities in the spacing of the turns, on the position sensitivity–defined as the dependence of the induced voltage on the coordinates of the current. The results in these examples agree with those that others have obtained by numerical methods or measurements with Rogowski coils. This technique may be used to quickly define the design specifications which are required to satisfy a specific upper limit for the positional sensitivity.