Tachometer utilizing a rotating transformer

Claim 1

A TACHOMETER ARRANGEMENT FOR MEASURING THE SPEED OF ROTATION OF A ROTARY MEMBER COMPRSING: A SOURCE OF A.C. VOLTAGE; A ROTARY TRANSFORMER INCLUDING A ONE-PHASE FIELD PIECE WINDING ELECTRICALLY CONNECTED ACROSS SAID A.C. VOLTAGE SOURVE AND MECHANICALLY CONNECTED TO ROTATE WITH SAID ROTARY MEMBER, AND A POLYPHASE STATOR WINDING; A PLURALITY OF RECTIFYING DETECTING CIRCUITS, ONE FOR EACH STATOR PHASE, EACH OF WHICH IS ELECTRICALLY CONNECTED ACROSS A RESPECTIVE PHASE OF SAID STATOR WINDING; A PLURALITY DIFFERENTIATION CIRCUITS, ONE FOR EACH OF SAID RECTIFYING DETECTING CIRCUITS, ONE FOR EACH OF SAID RECTIFYING DETECTING CIRCUITS, EACH OF WHICH DIFFERENTIATION CIRCUITS IS ONE OF SAID RECTIFYING DETECTING CIRCUITS; VOLTAGE RESPONSIVE MEANS; AND SWITCHING MEANS ELECTRICALLY CONNECTED TO ALL OF SAID DIFFERENTIATING CIRCUITS AND TO SAID UTILIZATION CIRCUIT FOR CONNECTING, AT EVERY MOMENT, SAID VOLTAGE RESPONSIVE MEANS TO ONLY THAT ONE OF SAID DIFFERENTIATING CIRCUITS WHICH IS PRODUCING THE HIGHEST VOLTAGE, SAID HIGHEST VOLTAGE BEING SUBSTANTIALLY PROPOTIONAL TO THE FREQUENCY OF ROTATION OF SAID ROTARY MEMBER.