Title of Invention

DRIVE CONTROL FOR SPINNING FRAME

Abstract

In a spinning frame drive a drive control unit (4) is being provided, which is being arranged between a power circuit (10) and an alternating-current power circuit (30). The drive control unit comprises a power supply unit (3), a measuring device (7), a voltage regulator (9) and a frequency regulator (11), by which the voltage U, the frequency n respectively, are controllable in an alternating-current power circuit (30) succeeding the power supply unit (3). The drive control unit (4) is designed in such a way, that the voltage and the frequency in the alternating-current power circuit (30) can be increased until a cut-off value n1 up to a value U1 = 400 V is reached, while when exceeding the cut-off frequency n1 = 90 Hz the voltage U is being maintained constant.

Full Text

The present invention relates to a spinning frame drive according to the preamble of the independent device claim. A spinning frame with a drive control of the type of art is described in the German patent application DE 196 37 757.9, according to which from a control unit, control frequencies are preset for the spindle drive as well as for the drafting roller. Conventionally electric motors - asynchronous motors, synchronous or reluctance motors - are being controlled by frequency regulators or frequency converters with current of a variable frequency n and a voltage U in such a way that on one side a maximum frequency and on the other side, independently of this, a certain maximum voltage or amperage is not being exceeded, so that the motor is not overcharged. In order to adapt a spinning frame, for instance a ring spinning frame, to produce a certain product, in particular a yarn with a given density and twist, in certain cases the transmission in the drive has to be changed in order not to overcharge the motor. The various ratios of transmission are being achieved in practice by mounting belt pulleys with varying diameters. Such re-fitting work reduces net efficiency of the spinning frame. The task as the object of the present invention is to arrange the drive system in such a way that with a single drive motor of variable performance P, which drives a shaft with adjustable revolution N, a possibly large performance range P = f(N) can be covered, so that with just a few drive transmissions a greater performance range can be covered, for which up to now various motors and/or numerous transmissions have been required. This task is being solved by a spinning frame drive of the characteristic features of the independent device claim. The depending claims relate to advantageous further embodiments. Accordingly the present invention provides a spinning frame drive with a drive control unit which is being arranged between a first power circuit and a second power circuit, with a power supply unit which by means of an alternating-current power circuit is being connected to at least one electric motor to drive work stations of a spinning frame, characterized in that to the power supply unit, in particular an inverted rectifier, means are being lined up in order to vary the power frequency on one hand, a frequency regulator in particular, and on the other hand means to change the power voltage, in particular a voltage regulator, and that said means are being laid out in such a manner that the voyage and the frequency in the alternating-current power circuit can be increased proportionally or non-proportionally up to a value for the voltage until a cut-off frequency of nl is reached, whereas if the cut-off frequency nl up to a maximum frequency of n2 is exceeded, then, the voltage can be maintained constantly at a maximum value. In the following the invention is being described according to an exemplified embodiment, wherein shows: fig. 1 a performance diagram P = f(N) fig. la a diagram with a performance curve of a motor (full line) and an envelope curve of a performance range with maximum performance of a spinning frame (dotted line) fig. lb a diagram of the moment of torque M = f(N) fig. 2 a schematic illustration of a drive control On the abscissa of the diagram in figure 1 the speed of rotations N of a shaft are plotted, which serves for the drive of one work station or for several work stations of the spinning frame. The ordinate stands for the drive performance P of a pertaining electric motor, for the spinning units depending on electric motors respectively. With reference to figures 1,1a lb and 2 the following different terms are being defined: PE maximum performance of an electric motor at a specific speed of rotation PI rated performance of a motor 5, for instance 45 kW P2 rated performance of a stronger motor 5, for instance 55 kW Pll performance on the shaft 60 with a motor of the performance PI and a first gear P12 performance on the shaft 60 with a motor of the performance PI and a second gear P13 performance on the shaft 60 with a motor of the performance PI and a third gear PM performance requirement of the working station as a function of the speed of revolutions N PMO performance requirement of the spinning frame at speed of revolutions NO, for medium yarn PGO performance requirement of a spinning frame for the production of coarse yarn PFO performance requirement of a spinning frame for the production of fine yarn, each at maximum possible performance. PMl performance requirement at operating speed Nl of the shaft 60 PM2 performance requirement at operating speed N2 of the shaft 60 M moment of torque of the motor, i.e. torque necessary for the spinning frame or for the respective structural group, with respect to the drive shaft for the spinning units ME torque of the electric motor MG torque for coarse yarn MM torque for medium yarn MF torque for fine yarn, each at stationary operation (idle runs) MB acceleration torque (MB = ME - MM) Nil speed limit of the spinning drive shaft with a performance requirement PM and a motor-gear combination with the performance curve P12 N12 maximum achievable speed of rotations on the shaft 60 with a motor of the maximum performance PI and a gear 6B It is assumed that the motor is specified for a maximum performance PI = 45 kW. With various transmissions in a gear 6 between the motor 5 and the drive shaft 60 it is possible to operate according performance curves Pll, P12, P13. Thereby it is assumed that the motor 5 or the drive control unit 4, preferably a frequency converter or frequency regulator which furnishes the motor 5 with power, can be operated up to a maximum frequency of 90 Hz. It is further assumed that the performance requirement at the working stations of the spinning frame, plotted over the speed of rotations N, follows the curve PM, if a specific product is to be manufactured. From the diagram in figure 1 it is clear, that the operating point PMO with the shaft speed NO cannot be run with any of the three performance curves Pll, P12, P13, since neither the revolution NO nor the performance PMO can be reached with the given ratios of transmission. With the application of an additional intermediate transmission it would be possible to obtain a performance line above line PM up to a maximum performance PI, however, the number of variants for refitting parts would thus further be increased. In order not to burden the customer with a larger number of different belt pulleys to be mounted, one would instead provide a stronger drive motor with a maximum performance P2 of for instance 55 kW right from the beginning, which motor would have the performance curve P21 at a specific transmission ratio. With such a motor a greater spectrum within diagram P = f(N) could be covered, including the performance curve PM up to performance of PM2 = P2. According to the invention, the drive control unit 4 of the spinning frame is now being designed in such a way, that the frequency of the alternating-current power, by which the motor 5 is being driven, can be increased above the rate of 90 Hz. However, the maximum power input of the motor is limited to the rate PI of for instance 45 kW. Assuming that the supply frequency can be increased so far that the shaft 60 reaches the speed N12, then the motor-gear combination can cover the whole performance range P = f(N) below the line Pll and PI up to the operating speed N12. In order to cover the performance characteristic range P = f(N) also in the range above the speed N12 up the maximum performance PI, another gear is to be provided, according to the performance curve P12 in diagram of figure 1. In this case the motor-gear combination reaches the speed N12, the maximum performance PI at a supply frequency of 90 Hz respectively, whereas, as mentioned before, said supply frequency can be increased further, for instance until the operating speed N13 at the crossing point of the lines P13 and Pi has been reached. In figure la once again the maximum performance PE of a motor is being plotted over the revolution N, below of it an envelope curve, which is the upper limit line of the performance range of a spinning frame for various possible articles. The points PGO, PNO and PFO are the performance values for a coarse, a medium and a fine yarn, in other words the performance requirement of all spinning units for the production of various yarns. Below, in figure lb, the torque pattern M = f(N) of an electric motor and the torque MG, MM, MF of the spinning frame with respect to the shaft 50 is being plotted over the speed, whereat curve pattern MG applies for a coarse yarn, MM for an intermediate yarn and MF for a fine yarn. From figure lb can be seen, that for the production of a fine yarn the torque MF plotted over the speed N clearly remains below the available torque ME of the motor 5. This means that for a certain speed N the surplus of the torque moment ME-MF is considerably higher than the surplus ME-MG. From this follows that during production of a fine yarn a considerably higher proportion of the overall-torque ME of the motor is being available as acceleration torque MB for the acceleration of the frame. This corresponds with the requirements, since a spinning frame has to start-up considerably faster for the production of fine yarn than during production of a coarse yarn. This makes clear that with a motor being specified according to the invention a larger variety of articles is possible without re-fitting work on the spinning frame drive. The wiring scheme according to figure 2 comprises the following components of the drive control unit: The drive control unit 4 is arranged between a first power circuit 2, 10 respectively and a second power circuit 30. Preferably a rectifier 1 is being placed between an alternating-current supply line 2 and a power supply unit 3 of the drive control unit 4. Said power supply unit 3 feeds an alternating-current power circuit 30 with current of a variable frequency, according to an operating programme for the spinning frame. The electric motor 5 is being connected by means of a gear 6 with a drive shaft 60, whereas, depending on the gear transmission, performance curves P11,P12 and P13 result. The shaft 60 drives the work stations 61,62 etc., for instance spinning units of a ring spinning frame. The drive control unit 4 comprises a measuring device 7 for the voltage U and the frequency n in the alternating-current power circuit 30. For the drive control unit 4 an input unit 15 is being provided, by which for example the actual frequency over the time can be entered in the alternating-current power circuit 30. The power supply unit 3 is being controlled by a voltage regulator 9 and a frequency regulator 11, whereas said units are being designed in such a way, that the voltage U and the frequency n within the alternating-current power circuit 30 can be increased more or less proportionally up to a value Ul of the voltage until a cut-off frequency of nl is being obtained, but that, however, in case that the cut-off frequency nl up to a maximum frequency of n2 is exceeded, the voltage can be maintained constant at a maximum value Ul. WE CLAIM: 1. A spinning frame drive with a drive control unit (4) which is being arranged between a first power circuit (10) and a second power circuit (30), with a power supply unit (3) which by means of an alternating-current power circuit (30) is being connected to at least one electric motor (5) to drive work stations (61 62) of a spinning frame, characterized in that to the power supply unit, in particular an inverted rectifier (3), means are being lined up in order to vary the power frequency on one hand, a frequency regulator (11) in particular, and on the other hand means to change the power voltage, in particular a voltage regulator (9), and that said means (9, 11) are being laid out in such a manner that the voltage and the frequency in the alternating-current power circuit can be increased proportionally or non-proportionally up to a value for the voltage until a cut-off frequency of nl is reached, whereas if the cut-off frequency nl up to a maximum frequency of n2 is exceeded, then, the voltage can be maintained constantly at a maximum value. 2. The spinning frame drive as claimed in claim 1, wherein the cut-off frequency is nl =90 Hz and that the voltage is limited to 400 V and that the frequency n can be increased to at least up to a maximum frequency n2 =110 Hz. 3. The spinning frame drive as claimed in any one of the preceding claims wherein the voltage U in the voltage regulator (9) within a frequency range n higher than 90 Hz can be maintained at 400 V. 4. The sparing frame drive as claimed in any one of the preceding claims wherein a drive control unit (4) with a power supply unit (3), a measuring device (7) for the frequency and voltage of the power at the output side of the power supply unit (3), as well as a voltage regulator (9) and a frequency regulator (11) are being provided. 5. The spinning frame drive as claimed in any one of the preceding claims, wherein the drive control unit is being provided in the form of a frequency converter or inverted rectifier. 6. A spinning frame drive with a drive control unit, substantially as herein described with reference to the accompanying drawings.

Documents:

1699-mas-1998 abstract-duplicate.pdf

1699-mas-1998 abstract.pdf

1699-mas-1998 claims-duplicate.pdf

1699-mas-1998 claims.pdf

1699-mas-1998 correspondences-others.pdf

1699-mas-1998 correspondences-po.pdf

1699-mas-1998 drawings.pdf

1699-mas-1998 form-19.pdf

1699-mas-1998 form-2.pdf

1699-mas-1998 form-26.pdf

1699-mas-1998 form-4.pdf

1699-mas-1998 form-6.pdf

1699-mas-1998 others.pdf

1699-mas-1998 petition.pdf

1699-mas-1998 description (complete)-duplicate.pdf

1699-mas-1998 description (complete).pdf