Digital magneto optical instrument for high voltage systems

Claim 2

A digital magneto-optical instrument transformer for high voltage systems in which two groups of Faraday shift devices are provided, comprising a first group with n Faraday shift devices A1 - An and a second group of n-1 Faraday shift devices B1 - Bn 1, the devices A1 - B1 producing equal rotation as a function of current, and one of each group of Faraday shift devices having the same rotation angle, and each succeeding pair having rotation, as dependence at angles which are twice as great as the prior pair; and all the Faraday shift devices are mounted between a first and a second polarizer which have polarization planes which differ by an angle which in the case of the devices Am where 1 < OR = m < OR = n is

Claim 3

A method of obtaining an n-place dual measured value using an instrument transformer as claimed in claim 1, wherein a light beam source provides light of the same intensity to a plurality of channels, each channel being formed by a first polarizer, a Faraday shift device and a second polarizer, and a measuring instrument for measuring light intensity indicative of the radiation passed by the individual channels, and a determination is made of whether the intensity of the radiation passed, after the polarizers, is above or below half the maximum possible Intensity or whether, after the polarizers, the intensity is above a first threshold which is chosen to be higher than half the maximum possible intensity, or is below a second threshold which is below half the maximum possible intensity, the nth place in the dual measured value being 1 or 0, depending upon whether the An channel produces more than half the maximum possible light intensity or less than half the maximum possible light intensity, the mth place in the dual number (where m < n) being 1 or 0, depending upon whether the intensity produced by the Am channel is above the first threshold or below the second threshold, and, if the light intensity is between these two thresholds, the Bm channel being used to determine the value of the place, in such a fashion that for a specific current for which the intensity produced by the Ai channel lies between the above mentioned thresholds, the ith place in the dual number is 1 where the intensity produced by the Bi channel is more than half the maximum possible intensity and the (i + 1)th place in the dual number is 0, or where the intensity produced by the Bi channel is less than half the maximum intensity and the (i + 1)th place is 1; and in that the ith place in the dual number is 0 in the other cases.

Claim 4

A digital magneto-optical instrument for measuring current, comprising a light energy source, a first polarizer receiving said light energy and polarizing the energy in a first direction, a plurality of pairs of light shift devices mounted so as to receive the polarized light energy from said first polarizer, an electrical conductor series wound about said plurality of pairs such that the number of turns between different pairs has a ratio of one to two in progression, a first plurality of polarizers mounted to receive the light energy after it has passed through one of each pair of light shift devices and the mth of said first plurality of light polarizers having its axis of polarization at an angle with said first direction of

Claim 5

A digital magneto-optical instrument for measuring current, comprising a light energy source, a first polarizer receiving said light energy and polarizing the energy in a first direction, a plurality of pairs of light shift devices mounted so as to receive the polarized light energy from said first polarizer, an electrical conductor series wound about said plurality of pairs such that the number of turns between different pairs has a ratio of one to two in progression, a first plurality of polarizers mounted to receive the light energy after it has passed through one of each pair of light shift devices and the mth of said first plurality of light polarizers having its axis of polarization at an angle with said first direction of

Claim 6

A digital magneto-optical instrument according to claim 3 wherein said detecting means indicate whether the energy passing said shift devices is above or below a threshold.