Starting a ring spinner, with a number of spinning stations each with a sliver drawing unit, has controlled spindle and drawing unit speeds to synchronize the drawing unit delivery with accelerating spindles

摘要

To start a ring spinning machine, the spindles and the sliver drawing units are started at least generally at the same time. On starting the drawing units, their acceleration is sufficiently low so that, within a given time span after the start, the successful yarn delivery is significantly lower than when the spindles are at their working speed. Before the spindles achieve their working speed, their rotary speed is brought into a parking rotary speed level (37), which is maintained until the yarn delivery reaches the operating yarn twisting rate with the action of the accelerating drawing units. When the required ratio is reached between the spindle speed to the drawing unit delivery, the spindles and the drawing units are accelerated to their working speed levels. To start a ring spinning machine, the acceleration of the drawing units at the starting phase is set at a level to give a yarn delivery increase of 0.3-1.0 m/min./sec. and especially 0.75 m/min./sec. The yarn delivery acceleration through the drawing units is increased to 4-6 m/min./sec. and especially 5 m/min./sec., at the latest up to achieving the operating yarn twisting level at the spindle parking speed, and preferably significantly before reaching this stage. The drawing unit acceleration is at a steady level for up to 1.0 sec. after the start, and especially 0.5 sec., and then it generally increases followed by a constant rate. The spindle acceleration is 3000-6000 rpm/sec. from the start until shortly before reaching the parking speed, and especially 5000 rpm/sec. The spindle parking speed is reached 0.8-3.0 sec. after the start, and especially 1.5 sec. The spindle acceleration is 1000-3000 rpm/sec. on achieving a synchronized state with the yarn delivery from the drawing units, and especially 2000 rpm/sec. The spindle parking speed is 50-20% of the operating speed, or 25%, at 400-8000 rpm and especially 5000 rpm. The difference in the speeds between the drawing units and the spindles is restricted, so that the yarn is not given an over-twist. The transit between the constant acceleration of the spindles at the starting phase and the parking speed is at a gentle rate (38) to prevent a balloon collapse. An independent claim is included for a ring spinning machine with a number of spinning stations, each with a sliver drawing unit. A rotary speed control unit controls the speeds of the drawing unit cylinders and the spindles, so that they are all started at the same time at different rates of acceleration, with a slower acceleration at the drawing units than at the spindles. Preferred Features: The rotary speed control is part of the central control system for the ring spinner, linked to two motor controls. At least one motor control is preceded by a nominal value processor. The input side of the nominal value processor is linked to a synchronizer, at the drive of the other motor unit. Preferably, the nominal value processor is at the spindle drive, and the synchronizer is at the drawing unit drive. The input side of the nominal value processor is also connected to a delay value transmitter at the central control. The motor control units are frequency setters, and especially rectifier inverters. At least one drawing unit control is linked to a drafting value transmitter at the central control. A multiplier is at each drawing unit control, linked to the output side of the nominal value processor on one side and, on the other side, is connected to the drafting value transmitter. At the drawing unit, at least one synchronous motor drives the rollers and especially a reluctance motor. The synchronizer is a pulse transmitter at the spindle drive motor. The nominal value processor has an integrator, a capacitance, a resistance and a switch. The input side of the nominal value processor is also linked to a comparator, for the comparison of input signals from the synchronizer and/or the delay value transmitter with stored values, to activate a barrier or release as appropriate. A frequency transmitter is at the output side of the nominal value processor to give a control frequency which is identical to the input frequency from the synchronizer, or a reduced frequency or no frequency during the run-up of a drive.