An injection method for self-calibration of inductive voltage dividers

Abstract

A selfcalibration or "boot-strapping" injec tion method for determining the voltage ratio and phase angle deviations of in d uctive voltage dividers utilizes s peciall y co nstru cted transformers for step and differential voltage injections without reference to th e fundamental elec tr ical units or stand ards. Co ns tru ction detai ls of transformers, derivation of e quations, a nd sys te matic evaluation of un ce rtainties ar~ prese nted. Cali bration of certain ratios involving a co mbination of dial settings on several decades can be obtain ed as read il y as th a t of a singl e decade. The accuracy of the results ob t.ai nab le at 10 kHz is within 2 X 10-7 of input for devia tions less than 10 ppm of input and within I X 10-" for deviation s up to 100 ppm of input. This sa me calibration technique can readily be used to cover a frequen cy range ~ml~Wk& .