Abstract
With a method for the safe starting and/or stopping a rotor of a rotor spinning machine for the production of yarn, with a multiple number of rotors, each of which rotates in a rotor housing covered by a lid, each rotor is driven by its own motor and is held in at least one radially and/or axially active magnetic bearing by means of a position controller. A data connection of the motor is provided with a control unit, in order to drive the rotor in various operating states. There is a check of the control for driving the rotor, the position control for the one or more active magnetic bearings, the data connection for controlling the motor and/or the properly closed lid, and, in the event that predetermined target values and/or states are not met, the start of the rotor is blocked or the motor that is already running is selectively stopped. A rotor spinning machine is suitable for carrying out the method.
Claims
1. Method for the safe starting and/or stopping of a rotor of a rotor spinning machine for the production of yarn, with a multiple number of rotors, each of which rotates in a rotor housing covered by a lid, whereas each rotor is driven by its own motor and is held in at least one radially and/or axially active magnetic bearing by means of a position controller, and a data connection of the motor with a control unit is provided, in order to drive the rotor in various operating states, characterized in that the control for the drive of the rotor the position control for the one or more active magnetic bearings and/or the data connection for controlling the motor are checked and, in the event that predetermined target values and/or states are not met, the start of the rotor is blocked or the motor that is already running is selectively stopped.
2-14. (canceled)
Description
[0024] Further advantages of the invention are described in the following embodiments. Thereby, different safety concepts are presented in the figures. The following is shown:
[0025] FIG. 1 the Start machine concept,
[0026] FIG. 2 the Emergency stop of the machine triggered concept,
[0027] FIG. 3 the Loss of the main voltage concept,
[0028] FIG. 4 the Loss of the power supply of the rotor drive concept,
[0029] FIG. 5 the Interruption of CAN communication concept,
[0030] FIG. 6 the Rotor housing is opened concept and
[0031] FIG. 7 the Machine is switched off concept.
[0032] Safety requirements that should be adhered to when operating the machine include, for example, that the rotor housing must remain closed while the rotor is above a certain speed value. In addition, the machine may start only if the box is closed and locked. The unlocking of the lid of the rotor housing cannot be bridged by the control unit, just as safety measures and control states may not be used for unlocking.
[0033] In order to enable the opening of the rotor housing, while the rotor is still moving and the energy of the rotor that is still rotating is below a defined value, a measured value redundant for the speed of the rotor must be determined. Such a redundant and discrete measured value may tap, for example, the voltage of the motor, which is essentially proportional to the speed of the rotor. From this, a logic signal may be generated, which means, for example, that the rotor speed is low.
[0034] If the rotor housing is opened while the rotor is rotating at a high speed (for example, because the shutter mechanism has failed), the motor is actively shut down. This may take place, for example, by the fact that the highest possible current acts on the motor during the first four seconds, in order to brake it electrically. In this manner, the rotor is stopped as soon as possible. Without such a measure, stopping the rotor would require approximately 60 seconds.
[0035] Preferably, all used sensor technologies are to, for example, generate a signal that indicates that the rotor housing is closed, just as the closing and emergency stop mechanisms are used in a redundant and fail-safe manner as far as possible. This ensures that, even with a failure of a first measure, a second measure and/or a second sensor means is provided in order to detect a state and/or a target value.
[0036] The following figures represent safety concepts that are used upon specific events.
[0037] The Start machine safety concept shown in FIG. 1 checks whether the rotor housing is closed, and whether a connection to the CAN communication between the rotor drive and the control unit is present and active. In addition, there may also be a check of whether the position control of the active magnetic bearing is operable. If all such tests are successfully completed, a DC/DC driver is switched on, and the drive is made ready for operation. If it is determined that one of the checks cannot be satisfactorily completed, this initiates the DC/DC driver being switched off and the low-side FETs being activated. The motor is thereby short-circuited and can no longer be operated. Thus, hazards caused by the accidental starting of the motor is ruled out.
[0038] According to FIG. 2, with the Emergency stop of the machine triggered safety concept, there is an initial check of whether the rotor drive is running. If this is affirmed, the speed of the rotor drive is lowered, at least to a minimum speed. That is, the speed of the motor for the spinning rotor is reduced. Thereby, with a preferred version of the invention, it is possible that the speed is reduced with a long ramp. This means that the speed is taken back very slowly. In particular, if the other drives of the spinning unit are synchronously and slowly driven back, it is possible that further yarn, in the ideal case even yarn that corresponds to the yarn produced in normal operation, can be spun. From a certain speed (for example, 15,000 rev/min), the rotor will no longer be able to produce a corresponding yarn. From this point in time, it is possible to stop the rotor rapidly, thus with a steep ramp. If it is determined that the rotor is no longer in rotational movement, or has only a very low rotational speed, such as less than 15,000 revolutions/min, the DC/DC driver is switched off and the low-side FETs are activated. Thus, the motor is short-circuited and runs down or is stopped by other means.
[0039] FIG. 3 describes the safety concept of Loss of the main voltage. Once again, there is an initial check of whether the rotor is running. If this is the case, the speed is reduced in a manner corresponding to the rotation values of the yarn before the spinning process is unstable. Thus, there is an attempt to carry out the stopping operation so that more yarn can be spun. Ideally, the yarn essentially corresponds to the yarn of the normal state of the spinning unit. If the spinning process is unstable (for example, if the rotational speed of the rotor is too low for spinning), measures are taken to reduce the speed of the rotor drive in a manner corresponding to the energy requirements of the machine. This means that the rotor is further reduced in its speed and, as a generator, supplies the magnetic bearing (for example) with power, so that the bearing of the rotor is further operable. If the rotational speed of the rotor is lowered further (for example, 15,000 revolutions/min), low-side FETs are activated and the motor is thereby short-circuited. Thus, the motor no longer produces power as a generator, and the magnetic bearings may no longer be supplied with a corresponding voltage. In this case, it is advantageous if fail-safe bearings are provided, which, upon a failure of the active magnetic bearings to be expected, intercept the rotor. The fail-safe bearings also bring about the fact that, upon the switching off or loss of the power supply, the bearing elements are not destroyed by the rotor. For example, it may be provided that, upon a failure of the active magnetic bearings, the rotor runs down to a stop and is braked there mechanically. It is thereby advantageous if the rotor is pushed in an axial direction, in which it can be intercepted in a stable manner. Finally, the DC/DC driver is switched off and the rotor housing can be opened.
[0040] FIG. 4 shows the safety concept of Loss of the power supply of the rotor drive. Here as well, there is an initial check of whether the rotor drive is running. If the rotor is not running, the DC/DC driver is switched off. However, if the rotor is still in motion, the speed of the rotor drive is reduced so that the self-supply through the operation of the generator is still ensured. From a certain speed (for example, 15,000 revolutions/min), low-side FETs are activated and the motor is short-circuited. If the active magnetic bearings likewise fail, the fail-safe bearings are used for the rotor. As soon as the rotor drive is no longer running, the DC/DC drivers are switched off. The rotor housing may be opened from such point in time by removing the lid.
[0041] FIG. 5 shows the safety concept of Interruption of CAN communication. The procedure is similar to the concept of Loss of the power supply of the rotor drive in accordance with FIG. 4. The speed of the rotor drive is reduced in order to ensure the self-supply. Preferably, the rotor drive is shut down over a long ramp, so that the spinning operation may still be maintained. Upon reaching a low speed (for example, 15,000 revolutions/min), low-side FETs are activated and, if necessary, the fail-safe bearings are used if the active magnetic bearings have failed. If the rotor is at a standstill, the DC/DC drivers are switched off. Thereafter, the safety concept for the event of Interruption of CAN communication is ended.
[0042] FIG. 6 describes the method of Opening of the rotor housing. If the rotor drive is still running, the rotor is applied with maximum current for up to 4 seconds. Very rapidly, the drive device is thereby braked electrically to a low speed. Under approximately 15,000 revolutions/min, the measures described above are then taken. Thus, the low-side FETs are activated and the motor is short-circuited. Where necessary, the fail-safe bearings are used if the active magnetic bearings have also failed to prevent damages. Finally, the DC/DC drivers are switched off, in order to have the spinning device in a safe condition.
[0043] According to FIG. 7, the DC/DC driver and low-side FETs remain inactive if, upon the Switching off of the motor, rotor drives and production group drives are no longer running. However, if it is determined that the rotor drives and production group drives are still running, all rotor drives are initially stopped. Then, all production group drives are stopped. Only if all the drives are switched off can the rotor housing locks of the spinning positions be released. Finally, it is ensured that the DC/DC driver and low-side FETs remain inactive, in order to keep the machine in a safe condition. This is also the case if, upon the first check, it is determined that the rotor drives and production group drives are no longer running. At that point, there is once again a check of whether the DC/DC driver and low-side FETs are inactive, in order to secure the machine.
[0044] With the described method for the safe starting and/or stopping of a rotor, it is highly important that the rotor is started only if all safety measures have been fulfilled, or if predetermined target values and/or states are reached. If this is not the case, the start of the rotor is blocked or the rotor that is already running is selectively stopped. By selectively stopping, damages to the machine and injuries to the operator are avoided, and, in the ideal case, during the stopping, yarn that is similar to the yarn produced in the normal spinning process is also generated. In addition to the safety aspects, the presented concept thus ensures a production increase, since, despite defective conduct of individual components being attempted, usable yarn can be produced.
[0045] In summary, some or all of the following states may be essential, in order
[0046] 1. to be able to start the rotor: [0047] the rotor housing must be closed in order to obtain AC power transmission [0048] all cables from the control unit to the spinning unit must be in order [0049] the control unit must function correctly in order to generate signals
[0050] 2. to have to stop the rotor: [0051] spin box opened [0052] damage to the spinning unit transformers [0053] broken or short-circuited cable from the control unit to the spinning unit [0054] malfunction of the sensors [0055] the control unit does not generate a safety signal
[0056] This invention is not limited to the illustrated and described embodiments. Variations within the scope of the claims, just as the combination of characteristics, are possible, even if they are illustrated and described in different embodiments.
