Dynamoelectric machine braking and magnetic holdign arrangement

Claim 1

FOR USE WITH A DYNAMOELECTRIC MACHINE HAVING A ROTOR AND SHAFT ASSEMBLY AND MEANS FOR REDUCING THE ROTATIONAL SPEED OF THE ASSEMBLY TO A PREDETERMINED SPEE, A DEVICE FOR STOPPING ROTATION OF THE ASSEMBLY WITHIN ONE REVOLUTION AT AND BELOW THE PREDETERMINED SPEED AND FOR PREVENTING ROTARY MOTION OF THE ASSEMBLY BELOW A PREDETERMINED TORQUE LOAD COMPRISING A STATIONARY MEMBER HAVING A YOKE ANNULUS OF MAGENTIC MATERIAL, AT LEAST FOUR EQUALLY SPACED APART MAGNETIC POLES EXTENDING INWARDLY FROM SAID ANNULUS TO FORM A BORE HAVING INNER POLE FACES OF ALTERNATING POLARITY, AND A ROTARY MEMBER ADAPTED TO BE CONNECTED TO REVOLVE WITH THE ROTOR AND SHAFT ASSEMBLY, SAID ROTARY MEMBER BEING FORMED OF MAGNETIZABLE MATERIAL AND HAVING A CENTRAL HUB SECTION AND A PLURALITY OF EQUALLY SPACED APART SALIENTS PROJECTING OUTWARDLY THEREFROM TOWARD THE STATIONARRY MEMBER IN SPACED RELATIONSHIP THEREWITH, THE RATIO OF THE NUMBER OF MAGNETIC POLES TO THE NUMBER OF SALIENTS BEING AN ODD INTEGER, AND THE TOTAL CIRCUMFERENTIAL LENGTH OF SAID SALIENTS AND MAGENT FACES ADJACENT THE BORE BEING NOT SUBSTANTIALLY LESS THAN 40% NOR SUBSTANTIALLY GREATER THAN 48% OF THE BORE CIRCUMFERENCE.