Patent ID: 7083134

Claim:
Yarn feeding device for weaving machines or knitting machines, the yarn feeding device comprising a housing in which a shaft provided with a winding element is rotatably supported, a storage surface for yarn windings formed by the winding element, sensor assemblies at least for scanning the yarn windings, an electric motor consisting of a stator part and a rotor which is connected to the shaft for rotating the winding element, and an electronic speed control device of the electric motor which electronic speed control device is connected for signal transmissions with the sensor assemblies and the electric motor, and a position control and position observation at least for adjusting the winding element by the electric motor into at least one predetermined rotary stop position in relation to the housing, wherein the electric motor is a synchronous motor controlled by the speed control device, the speed control device having a microprocessor for a permanent vector control of the electric motor by detecting the relative rotary position of a vector of the rotor to determine the relative rotary rotor position and by rotating a stator vector in relation to the detected vector of the rotor by sinusoidal stator actuation, and wherein the predetermined rotary stop position of the winding element is adjusted by stopping the electric motor by use of the permanently determined vector control information in the speed control device.