Patent GB-1324436-A (GB)
Title: Drive apparatus for driving spindles of textile machines
IPC: D01H1/26
Filed: 1970-10-12
Abstract: 1324436 Control of electric motors ZINSERTEXTILMASCHINEN GmbH 12 Oct 1970 [21 Oct 1969] 48364/70 Heading H2J [Also in Divisions D1 and G3] The tension in a synthetic thread being stretched and twisted and wound on to bobbins by a textile machine having a plurality of winding stations and bobbin driving asynchronous motors is maintained constant by thyristor control of the speed of a respective motor in dependence upon deviation of the detected tension from a predetermined value thereof. The speed of a bobbin driving motor is initially at its highest value when a respective bobbin is empty and is reduced and controlled automatically when winding commences. In the machine, winding stations are grouped in pairs-as stations 12, 13 (Fig. 1) which are fed alternately from a common feed station 11, whenever one bobbin is full the thread being cut and automatically directed on to the other bobbin. Thread is drawn off a reel 15 by a synchronous motor 35, passing through a stretch bay 19 over a heating plate 20 and is directed by a selector guide head 24 through either duct 25 or 26 into caps 30, 30<SP>1</SP> respectively depending upon which station is currently winding a bobbin. The ducts have outlets 27. The caps 30, 30<SP>1</SP> are belt driven by a common constant speed synchronous motor (not shown). The caps receive bobbin spindles 34, 34<SP>1</SP> which are vertically moveable up and down within by means of hydraulic cylinders 32, 32<SP>1</SP> and are driven by the asynchronous motors 31, 31<SP>1</SP>, respectively, preferably in opposite direction of rotation to the caps. The spindles are shown in their reretracted lowest positions, spindle 34 carrying a full bobbin. Thread tension is sensed by a detector 22. The thread is blown through nozzles 37, 38 and ducts 23, 25, 26 by compressed air from ducts 39, 40. Control of tension (Fig. 2).-Assuming motor 31<SP>1</SP> is about to wind a bobbin, it is initially connected directly through a switch arrangement to an A.C. bus-bar 61 to run at its highest speed. At the commencement of winding, the switch arrangement which is coupled to and controllable by the thread route selector head 24 automatically reconnects the motor to the busbar via a thyristor control unit comprising a pair of anti-parallel thyristors per phase. The same thyristor control unit is used when the other motor is winding. The firing angle of the thyristors is controlled in dependence upon deviation in the actual tension sensed by the detector 22 from a desired value preset on a unit 42. Alternatively full half-cycles may be passed by the thyristor consecutively followed by a period in which the thyristor is blocked over several half cycles. Thereby the mean voltage applied to the motor and hence the motor speed is adjusted to maintain the tension constant. The bus-bars 61 are connected to a frequency converter e.g. the D.C. motor/alternator set 60 (as shown) or to a static frequency converter, the output frequency of the converter being adjustable. The switching arrangement is illustrated in Fig. 3 (not shown). Alternatively the motor's speed may be controlled in dependence upon the diameter of bobbin load.