Polyphase multi-element induction meter with common eddy current armature having solid and slotted laminations

Claim 1

IN AN INDUCTION DEVICE RESPONSIVE TO AN ALTERNATING QUANTITY, A PLURALITY OF ELECTROMAGNETIC STRUCTURES EACH HAVING AN AIR GAP AND ELECTRORESPONSIVE MEANS EFFECTIVE WHEN ENERGIZED FOR PRODUCING A SHIFTING MAGNETIC FIELD IN THE AIR GAP, AN ELECTROCONDUCTIVE ARMATURE MOUNTED FOR ROTATION RELATIVE TO THE ELECTROMAGNETIC STRUCTURES ABOUT AN AXIS, SAID ARMATURE HAVING A PORTION DISPOSED IN EACH OF THE AIR GAPS TO DEVELOP A TORQUE ACTING BETWEEN THE ELECTROMAGNETIC STRUCTURES AND THE ARMATURE ABOUT THE AXIS IN RESPONSE TO SAID SHIFTING MAGNETIC FIELDS, SAID ARMATURE COMPRISING A PLURALITY OF LAMINATIONS OF ELECTROCONDUCTIVE MATERIAL POSITIONED ADJACENT TO EACH OTHER, EACH HAVING A PORTION DISPOSED IN EACH OF THE AIR GAPS, AND SUBSTANTIALLY SYMMETRIC RELATIVE TO SAID AXIS, A FIRST ONE OF SAID LAMINATIONS BEING SLOTTED TO LIMIT THE PATHS THEREIN FOR EDDY CURRENTS PRODUCED BY THE SHIFTING MAGNETIC FIELDS AND A SECOND ONE OF SAID LAMINATIONS HAVING LESS THAN THE NUMBER OF SLOTS PROVIDED IN THE FIRST ONE OF SAID LAMINATIONS TO PROVIDE SUBSTANTIAL PATHS FOR EDDY CURRENTS PRODUCED IN THE SECOND ONE OF SAID LAMINATIONS BY THE SHIFTING MAGNETIC FIELDS.