Yarn-tensioning device and arrangement and method for operating a creel
The invention relates to a yarn-tensioning device for producing a specific thread pull on a thread ( 5 ) that is unwound from a winding point ( 7 ) of a creel ( 2 ) and is guided to a warping machine arrangement ( 1 ). Said yarn-tensioning device comprises a rotating body ( 18 ) which is at least partially wound round by threads and an electric motor ( 19 ) which is connected to the rotation body. Said motor ( 19 ) is equipped with at least one brake transistor ( 20 ) for discharging excess energy produced when the generator of the motor is operated, said brake transistor being able to convert generator energy, arising when the generator is operated, into heat.
1. A yarn-tensioning device for generating a specific yarn tension on a yarn which is drawn off from a winding station of a creel and is delivered to a winding apparatus, said yarn-tensioning device comprising
a rotary body around which the yarn can be at least partially looped, and
an electric motor which is connected at the rotary body and with the aid of which the rotary body can be driven, said motor having a generating mode,
wherein, to discharge excess energy in the generator mode of the motor, the motor is equipped with at least one brake transistor, by means of which electrical current produced in the generator mode can be converted into heat, wherein
the brake transistor is arranged on a side of the motor which faces the rotary body, so that air generated by movement of the rotary body cools the brake transistor.
2. The yarn-tensioning device as claimed in claim 1 , wherein the brake transistor is mounted on a disk-shaped circuit board which is fastened to the inside of the end face of the motor housing.
3. The yarn-tensioning device as claimed in claim 1 , wherein the brake transistor has a top side which forms a contact face with the inside of the end face of the motor housing, and to compensate for tolerances in the region of the contact face, a heat-conducting paste is provided between the brake transistor and the motor housing.
4. The yarn-tensioning device as claimed in claim 1 , wherein the brake transistor is mounted on a top side of the circuit board, and conductor means emanate from the brake transistor and are led through the circuit board to the rear side of the circuit board in order to make an operative electrical connection between the brake transistor and motor in the generator mode.
5. The yarn-tensioning device as claimed in claim 4 , wherein the free ends of the conductor means form on the rear side of the circuit board contact feet which are in electrical contact with a circuit board for the motor control of the motor.
6. The yarn-tensioning device as claimed in claim 1 , wherein two brake transistors are provided.
7. The yarn-tensioning device as claimed in claim 1 , wherein the rotary body is designed as a yarn wheel, in the circumferential region of which an approximately V-shaped groove for receiving the yarn is provided.
8. The yarn-tensioning device as claimed in claim 1 , wherein the rotary body has, on the underside facing the motor, at least one vane element for cooling in the generator mode.
9. An arrangement for operating a creel for a winding plant having a plurality of winding stations and a winding machine for the joint winding of a plurality of yarns of identical or different generic type which are drawn off from the winding stations, and
at least one yarn-tensioning device according to claim 1 assigned to each winding station.
10. A method for operating a creel for a winding plant with a plurality of winding stations, in which a plurality of yarns of identical or different generic type are drawn off jointly from the winding stations by means of a rotating winding machine, at each winding station the yarn being acted upon with a variable braking force in order to generate a specific yarn tension with the aid of at least one yarn-tensioning device according to claim 1 .
11. A yarn-tensioning device for generating a specific yarn tension on a yarn which is drawn off from a winding station of a creel and is delivered to a winding apparatus, said yarn-tensioning device comprising
a rotary body around which the yarn can be at least partially looped, and
an electric motor which is connected at the rotary body and with the aid of which the rotary body can be driven, said motor having a generating mode,
wherein, to discharge excess energy in the generator mode of the motor, the motor is equipped with at least one brake transistor, by means of which electrical current produced in the generator mode can be converted into heat, wherein
the motor has a motor housing with an end face through which a motor shaft passes, the rotary body fastened to the motor shaft being arranged on the outside of the end face and the brake transistor being arranged on the inside of the end face.