Multiple-clutch electromagnetic torque devices

Claim 1

ELECTROMAGNETIC CLUTCH APPARATUS COMPRISING AT LEAST TWO OPPOSITELY MAGNETICALLY POLARIZED FIELD COIL WINDINGS ADAPTED TO BE ELECTRICALLY EXCITED FROM TERMINALS OF A POWER SOURCE AND WHICH ARE SO CLOSELY LOCATED AS TO BE SUBJECT TO MUTUAL MAGNETIC FIELD INTERLINKAGE BY LEAKAGE FLUX IF ONLY ONE WINDING IS EXCITED, A CONTROL CIRCUIT INCLUDING AT LEAST A PORTION OF ONE OF SAID FIELD COIL WINDINGS AND AT LEAST A PORTION OF THE OTHER OF SAID FIELD COIL WINDINGS, SAID CONTROL CIRCUIT INCLUDING CONDUCTIVE CONNECTIONS AND SWITCH MEANS ADAPTED TO CONNECT SAID PORTIONS FOR CURRENT FLOW THERETHROUGH IN SERIES CIRCUIT RELATION BETWEEN SAID TERMINALS, AND CONTROL MEANS INCLUDING A RESISTOR ADAPTED TO PRODUCE A NUMBER OF AMPERE TURNS IN EITHER FIELD COIL WINDING WHICH ARE SUBSTANTIALLY DIFFERENT AND LESS THAN THE NUMBER OF AMPERE TURNS IN THE OTHER FIELD COIL WINDING AND OF A VALUE WHICH WILL PRODUCE A MAGNETIC FIELD SUBSTANTIALLY EQUAL IN MAGNITUDE AND OPPOSITE IN POLARITY TO THAT OF THE LEAKAGE FLUX FROM SAID OTHER FIELD COIL WINDING, SAID SWITCH MEANS ADAPTED IN A FIRST POSITION TO CONNECT ONE OF SAID WINDING PORTIONS IN SERIES WITH THE OTHER WINDING PORTION AND TO SHUNT SAID RESISTOR ACROSS SAID OTHER WINDING PORTION, AND ADAPTED IN A SECOND POSITION TO CONNECT SAID OTHER WINDING PORTION IN SERIES WITH SAID ONE WINDING PORTION AND TO SHUT SAID RESISTOR ACROSS SAID ONE WINDING PORTION, WHEREBY THE EFFECT OF LAKAGE FLUX AS TO EITHER WINDING MAY BE SUBSTANTIALLY CANCELLED.