Patent ID: 9188610
Filing Date: 2015-11-17
Classification: G01R

Abstract:
1. Apparatus for measuring a plurality of primary electric currents in a non-contact manner by utilizing a plurality of current transformers; each of said current transformers being coupled with one of said primary electric currents; each of said current transformers comprising a magnetic core and a secondary winding; each of said secondary windings conducting one of a plurality of secondary electric currents; said apparatus comprising: a. a current-sensing means for periodically receiving each of said secondary electric currents and for providing a first information signal containing information about each of said secondary electric currents; b. a voltage control circuit for periodically controlling a voltage across each of said secondary windings; c. a current transformer selection circuit for periodically connecting each of said secondary windings to said current-sensing means and said voltage control circuit; d. a power supply circuit for providing operating power to said voltage control circuit; e. and a control circuit for receiving said first information signal and for controlling said voltage control circuit and said current transformer selection circuit; said control circuit being connected to said current-sensing means, said voltage control circuit, and said current transformer selection circuit; said voltage control circuit providing a first voltage at a first output; said voltage control circuit being connected to said power supply and said current transformer selection circuit; said voltage control circuit being controlled by said control circuit; said current transformer selection circuit comprising a first plurality of electronic switches; said current transformer selection circuit being connected to said first output and having connecting means for connecting to each of said secondary windings; said current transformer selection circuit being controlled by said control circuit; said current transformer selection circuit functioning to periodically connect each of said secondary windings one-at-a-time to said first output and to periodically route each of said secondary electric currents one-at-a-time through said current sensing means; said apparatus thereby providing for selection and control of each of said current transformers and thereby providing for periodic measurement of each of said primary electric currents.