Direct current motor with transistorized power supply

Claim 1

IN A D.C. MOTOR HAVING A STATOR AND A ROTOR, ARMATURE WINDINGS, A POWER SUPPLY, ARMATURE TRANSISTORS CONNECTING THE POWER SUPPLY TO THE ARMATURE WINDINGS, A CONTROL CIRCUIT CONNECTED TO THE ARMATURE TRANSISTORS FOR CONTROLLING THE SAME IN DEPENDENCE UPON THE RELATIVE ANGULAR POSITION BETWEEN THE STATOR AND ROTOR, THE CONTROL CIRCUIT INCLUDING AN OSCILLATORY CIRCUIT INCORPORTATING A CONTROL TRANSISTOR, AND SPEED REGULATING MEANS CONNECTED TO THE CONTROL CIRCUIT FOR APPLYING THERETO A TACHOMETER POTENTIAL, DEPENDENT ON THE ROTATIONAL SPEED OF THE MOTOR WHICH RENDERS THE CONTROL CIRCUIT INEFFECTIVE AT A GIVEN PREDETERMINED ROTATIONAL SPEED, THE IMPROVEMENT THAT SAID TACHOMETER POTENTIAL IS DERIVED FROM SAID ARMATURE WINDINGS WHILE THE SAME ARE BLOCKED FROM SAID POWER SUPPLY BY SAID ARMATURE TRANSISTORS.