Magneto-optical electric current sensing arrangement

Claim 1

A MAGNETO-OPTICAL TRANSDUCER FOR MEASURING VARYING CURRENTS IN A POWER LINE OVER A CURRENT RANGE EXTENDING FROM A FRACTION OF RATED CONTINUOUS CURRENT TO AT LEAST TWENTY TIMES RATED CONTINUOUS CURRENT, COMPRISING: (A) AN OPTICAL ELEMENT HAVING A PAIR OF SPACED-APART END SURFACES, (B) MEANS FOR DIRECTING A BEAM OF LIGHT THROUGH SAID OPTICAL ELEMENTS BETWEEN SAID END SURFACES, (C) A POLARIZER THROUGH WHICH SAID BEAM OF LIGHT IS TRANSMITTED PRIOR TO ENTERING SAID OPTICAL ELEMENT IS SUBSTANTHAT LIGHT ENTERING SAID OPTICAL ELEMENT IS SUBSTANTIALLY PLANE POLARIZED, (D) AN ANALYZER THROUGH WHICH SAID BEAM OF LIGHT IS TRANSMITTED UPON LEAVING SAID OPTICAL ELEMENT, (D) MEANS SENSITIVE TO SAID ELECTRIC CURRENTS FOR DEVELOPING A MAGNETIC FIELD THAT HAS AN INTENSITY THAT VARIES AS A DIRECT FUNCTION OF THE MAGNITUDE OF SAID ELECTRIC CURRENT, (E) MEANS FOR APPLYING SAID MAGNETIC FIELD TO SAID OPTICAL ELEMENT IN A DIRECTION GENERALLY PARALLEL TO THE PATH FOLLOWED BY SAID BEAM OF POLARIZED LIGHT TO ROTATE THE PLANE OF VIBRATION OF SAID BEAM OF POLARIZED LIGHT THROUGH AN ANGLE VARYING IN MAGNITUDE AS A DIRECT FUNCTION OF THE MAGNETIC FIELD INTENSITY, (E) SAID MAGNETIC FIELD BEING SO CONTROLLED THAT CURRENTS OF TWENTY TIMES RATES CONTINUOUS CURRENT PRODUCE ANGULAR ROTATIONS NO GREATER THAN 20 DEGREES,