Rotary actuator

Abstract

The invention relates to a rotary actuator (1) comprising: - a stator (10), - at least one stator coil (11) which is connected to the stator (10) in such a way that a force acting on the stator coil (11) is transferred to the stator (10); - an armature (20) rotatable about an axis of rotation (2) relative to the stator (10), - at least one armature coil (21) which is connected to the armature (20) in such a way that a force acting on the armature coil (21) is transferred to the armature (20); - Power lines (3) through which at least one stator coil (11) can be energized, - Cable (4) through which the at least one armature coil (21) can be energized, - a rotation angle limiting device (5) by which rotation of the armature relative to the stator is limited to a rotation angle range of 0 to 359 degrees.

Description

[0001] The present invention relates to a rotary actuator, a method for operating the rotary actuator, and various uses of the rotary actuator.

[0002] Switching devices for low-voltage and high-voltage applications, such as load switches, disconnect switches, or circuit breakers, can inherently have two mechanical disadvantages: First, when the switching device is energized, i.e., when the contact system closes, the mass of the moving contact, and additionally the mass of the switch mechanism, is abruptly stopped at the galvanic contact point, which can lead to contact bounce. Second, due to arcing, the two contacts can easily weld together. Therefore, when the switching device is energized, i.e., when the contact system opens, a so-called break-up shock, i.e., a higher force for contact separation, must be generated to break up any welded contact system.Conventional actuators for switching devices, which convert the rotary motion of a drive shaft into the linear motion of the moving contact, deliver a more or less continuous force precisely within this range. Examples of these actuators for switching devices include spring actuators and magnetic actuators (classic solenoid).

[0003] Current approaches aim to improve contact bounce behavior through special kinematics, such as deflection levers to control the speed profile, or by using servomotors with complex control systems to decelerate the moving contact just before galvanic contact. However, the break-stop effect is currently achieved with additional accelerated masses, which in turn require a higher overall drive energy.

[0004] Main drives for vacuum tube circuit breakers sometimes use linear or rotary actuators based on solenoids. These actuators inherently have relatively low forces or torques at the start of movement due to a large air gap, which leads to low efficiency. This means a disproportionately large amount of electrical energy must be expended at the beginning of the movement to initiate it. Currently, the initial force is increased by using specific air gap geometries. However, this requires a relatively complex armature and / or stator geometry and reduces the force in the remaining stroke range.

[0005] Switchgear often incorporates a short-circuiting device to extinguish an arc fault before it causes significant damage from a metallic short circuit. The short-circuiting device must operate within milliseconds. Explosives are typically used as the activating agent, but this results in contamination of the system and the release of toxic substances. Alternatively, short-circuiting devices powered by stored spring energy are used, though these require considerable mechanical effort.

[0006] There is therefore a need for an improved drive that can be used in switching devices, e.g. circuit breakers, and in short-circuiting devices.

[0007] This problem is solved according to the invention by a rotary actuator with the features specified in claim 1, a method with the features specified in claim 9, a switching device with the features specified in claim 13, a switching device with the features specified in claim 14 and a short-circuiting device with the features specified in claim 15.

[0008] The rotary actuator according to the invention comprises a stator. The stator has at least one stator coil, which is connected to the stator in such a way that a force acting on the stator coil is transmitted to the stator. The rotary actuator has an armature. The armature is rotatable about an axis of rotation relative to the stator. The armature has at least one armature coil, which is connected to the armature in such a way that a force acting on the armature coil is transmitted to the armature. The rotary actuator has electrical leads through which the at least one stator coil can be energized. The rotary actuator has electrical leads through which the at least one armature coil can be energized.

[0009] The object is further achieved according to the invention by a method for operating the aforementioned rotary actuator, wherein a current pulse causes a braking or acceleration pulse. The triggering of the current pulse is triggered by an angular position of the armature relative to the stator.

[0010] The object of the invention is further achieved by a switching device with at least one switch, wherein a rotary actuator according to the invention functions as an auxiliary drive for the switch. The switching device has a rotating shaft and a main drive acting on the rotating shaft. A movement of a moving contact of the at least one switch is caused by a rotation of the rotating shaft. The switching device also has a rotary actuator as described above, wherein the rotary actuator functions as an auxiliary drive for the switch. The armature of the rotary actuator is arranged non-rotatably on and coaxially with the rotating shaft. With a properly designed rotary actuator, the moving contact can thus be briefly decelerated or accelerated just before contacting the fixed contact in the switch-on case, in order to improve the contact bounce behavior of the switching device. In the switch-off case, an additional acceleration pulse can be supplied, which acts as a break-stop impulse.Such a rotary actuator, preferably a relatively small one, can be fitted as an auxiliary drive to virtually any switch with a rotating shaft. This is particularly beneficial for medium-voltage circuit breakers with high breaking capacity and thus typically large moving contact masses, allowing for improved contact bounce and break-out behavior. It can be especially advantageous if the rotary actuator is coupled directly to the moving contact, rather than via intermediate springs. If a servo motor serves as the switch's primary drive, no complex servo motor control is required; only a precise reference signal with respect to the galvanic contact is needed to trigger the current pulse for the rotary actuator. Such reference contacts are common, for example, in high-voltage circuit breakers that are switched synchronously with the mains supply (Hall sensor).The rotary actuator generates a very strong torque pulse that is available almost instantly. This contrasts sharply with relatively slow magnetic drives, where a soft iron magnetic circuit must first be magnetized to build up the force or torque.

[0011] The object is further achieved according to the invention by a switching device with at least one switch, wherein a rotary actuator according to the invention functions as a main drive of the switching device. The switching device has a rotary actuator as described above, wherein the rotary actuator functions as a main drive of the switch and wherein a movement of a moving contact of the at least one switch is caused by a rotation of the rotary actuator. Such a rotary actuator can be used, by means of suitable timing, to drive the entire switch or the entire switching device.

[0012] The rotary drive according to the invention can be used as a main drive for a switching device, since the current pulses can be repeated at short intervals with suitable timing control in order to generate several, even relatively strong, torque pulses. The relatively fast switching sequences required for this can be achieved by a suitable design of an electrical energy storage device, e.g., a capacitor, and a charging technology for the electrical energy storage device.

[0013] The pulse spacing and pulse length of the current pulses can be adjusted to the required torque. Crucially, the current rise is relatively rapid, generating the torque. Therefore, the coil current can be switched off shortly after reaching its maximum current by suitable power electronics to conserve energy, preferably supplied by a capacitor bank (i.e., several capacitors connected in series). This allows pulses to be generated at intervals of just a few milliseconds when needed to drive the switching device. The pole pitch (i.e., the number of partial coils in the armature or stator) can be adjusted as required, in conjunction with the electronic timing of the current supply, to adapt the torque to the specific demand.

[0014] The problem is further solved according to the invention by a short-circuiting device. The short-circuiting device has a rotary actuator, as described above. The rotary actuator causes a movement of a closing contact of the short-circuiting device. The rotary drive according to the invention can be used in a short-circuiting device where, for example, knife contacts, similar to a disconnect switch, are closed relatively quickly to create a metallic short circuit. An electrical energy storage device, e.g., a capacitor, is discharged into the coil system, thereby triggering a relatively rapid rotary movement of a closing contact. In contrast to short-circuiting devices driven by explosives, the drive by the rotary actuator can be used repeatedly.

[0015] An alternative application of the rotary actuator is an impact wrench for loosening wheel bolts on a motor vehicle. This is possible because the rotary actuator can generate one force pulse per current pulse through the coils, thus producing a repetitive torque (breaking impact) for loosening seized bolts.

[0016] The invention is based on a rotary actuator with a limited rotation angle. The principle of the invention is a precisely timed pulse current through two or more coils, which preferably partially overlap. A first coil is wound in the stator, which is rigidly connected to the switch housing, and a second coil is wound on the armature. After suitable triggering, e.g., by a Hall sensor to generate a trigger signal, or by determining a trigger point from typical points in the current waveform of a main magnetic drive (if present), an electrical energy storage device such as a capacitor can be discharged pulse-likely through the series- or parallel-connected coils. This pulse current results in a virtually instantaneous torque pulse, the sign of which can be defined by the current direction, e.g., in the armature coil.

[0017] A Lorentz force acts between the energized coils, and a reluctance force exists throughout the entire armature-stator assembly. The resulting force is relatively dynamic and effective over a relatively long stroke: relatively high impulse torques can be achieved per current pulse. The generated force is immediately available at full magnitude at the armature's initial position. Furthermore, the rotary actuator is easily scalable.

[0018] The pulse spacing and pulse length of the current pulses can be adjusted to the required torque. The rate of increase of the current that generates the torque is crucial for the torque level. Therefore, the coil current can be switched off shortly after reaching its maximum current by suitable power electronics to conserve energy, preferably from a capacitor bank (i.e., several capacitors connected in series). This allows pulses to be generated at intervals of a few milliseconds when needed to drive the circuit breaker. The pole pitch (i.e., the number of partial coils in the armature or stator) can be adjusted as required, in conjunction with the electronic timing of the coil current, to adapt the torque to the specific demand.

[0019] Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0020] According to the invention, the stator and armature rotate only over a defined, limited angular range. Since the armature does not continuously rotate in one direction as in an electric motor, but only performs back-and-forth rotations over a limited angular range, no sliding contacts are required to energize the at least one armature coil; instead, only flexible conductor connections between the at least one armature coil and a voltage source are needed.

[0021] According to a preferred embodiment of the invention, the rotation of the armature relative to the stator is limited to a rotation angle range of 0 to 90 degrees, more preferably from 0 to 60 degrees. An advantage of this is that the current supply to the armature is simplified and can be achieved with flexible cables, without the need for sliding contacts.

[0022] According to a preferred embodiment of the invention, the armature and the stator each consist at least partially of soft magnetic material. An advantage of this is that the reluctance force in the metallic armature and stator is also utilized.

[0023] According to a preferred embodiment of the invention, the armature and the stator are each laminated. The lamination planes run transversely to the longitudinal axis of the armature and stator. An advantage of this is that the longitudinal lamination reduces eddy currents.

[0024] According to a preferred embodiment of the invention, the armature and the stator each have the form of a hollow cylinder. The armature is arranged coaxially to the stator within the stator. An advantage of this is the compact design.

[0025] According to a preferred embodiment of the invention, the armature has grooves on its outer circumference into which the at least one armature coil is inserted. Depending on the surface design, the grooves can be closed with wedges to prevent the armature winding from being dislodged by centrifugal forces. An advantage of this design is its compact form.

[0026] According to a preferred embodiment of the invention, the stator has slots on its inner circumference into which the at least one stator coil is inserted. Depending on the surface design, the slots can be closed with wedges to prevent the stator winding from being dislodged by centrifugal forces. An advantage of this is the compact design. Since the centrifugal forces act outwards and press the stator coils into the slots, slots on the inner circumference of the stator generally do not need to be closed.

[0027] According to a preferred embodiment of the invention, the at least one stator coil and the at least one armature coil are connected in series. An advantage of this is that an impulse current through the series-connected coils results in a virtually instantaneous torque pulse, whereby the sign of the torque pulse can be defined by the current direction, e.g., in the armature coil.

[0028] According to a preferred embodiment of the invention, the number of pole pairs in the armature and stator is the same. For example, the armature has three strands, each with an armature coil; the coils generate magnetic fields whose axes are oriented in the directions 0°, 120°, and 240°. The stator is configured analogously. Depending on the requirements, the number of pole pairs can be such that the armature and stator each have a 3-pole, 4-pole, or 5-pole pitch. Depending on the requirements, the armature and stator can also have any other feasible pitch. An advantage of this is that the rotary actuator can be adapted to different requirements by selecting the appropriate pitch.

[0029] According to a preferred embodiment of the invention, the rotary actuator has an electrical energy storage device, e.g., a capacitor, which can discharge its charge into the at least one stator coil and / or at least one armature coil. The electrical energy storage device can be discharged in pulses via the series- or parallel-connected coils. An advantage of this is that such a pulse current results in a virtually instantaneous torque pulse, whereby the sign of the torque pulse can be defined by the current direction, e.g., in the armature coil.

[0030] According to a preferred embodiment of the invention, the rotary actuator comprises a control unit that controls the current flow to the at least one stator coil and the at least one armature coil. Following suitable triggering, e.g., by a Hall sensor to generate a trigger signal at the galvanic contact point of a vacuum tube or by determining a trigger point from typical points in the current waveform of a main magnetic drive of a switching device (if present), an electrical energy storage device, e.g., a capacitor, can be discharged intermittently via the series- or parallel-connected coils. Upon receiving a trigger signal, the control unit can cause an electrical energy storage device, such as a capacitor, to discharge its electrical charge into the at least one stator coil and the at least one armature coil.One advantage is that the control unit allows the movements of the rotary actuator to be adapted to different requirements.

[0031] According to a preferred embodiment of the invention, the control unit is configured to control an electronic reversal of the coils. The coils are thus reversed electronically, not by means of sliding contacts. An advantage of this is that this electronic reversal method is simpler and causes less wear than an electromechanical reversal method.

[0032] According to a preferred embodiment of the invention, the at least one stator coil and the at least one armature coil overlap radially. The achievable torque depends on the degree of overlap. An advantage of this is that the rotary actuator can be adapted to different requirements by selecting the degree of coil overlap.

[0033] According to a preferred embodiment of the invention, a current pulse, triggered by an angular position of the armature relative to the stator, generates a braking or acceleration pulse. An advantage of this is that the movements of the rotary actuator can be adapted to different requirements by means of the current pulse.

[0034] According to a preferred embodiment of the invention, several successive current pulses cause a continuous movement of the armature, e.g., over an angular range greater than 15 degrees. An advantage of this is that the movements of the rotary actuator can be adapted to different requirements by means of the current pulses.

[0035] According to a preferred embodiment of the invention, one or more current pulses exhibit a current change dI / dt. An advantage of this is that the movements of the rotary actuator can be adapted to different requirements by adjusting the magnitude of the current change.

[0036] According to a preferred embodiment of the invention, in a starting position, a first stator coil and an armature coil overlap; a current pulse is triggered, causing movement of the armature so that the overlap of the first stator coil and the armature coil increases, and another current pulse is triggered when the overlap of the first stator coil and armature coil has decreased again. An advantage of this is that a relatively high torque can be generated over a relatively large rotation angle of the armature.

[0037] According to a preferred embodiment of the invention, the rotary actuator has a rotation angle limiting device that restricts the rotation of the armature relative to the stator to a predetermined range of angles. However, the rotation angle limitation only exists in the sense that repeated rotation of the armature in one direction, as in conventional motors, is not intended, and that any repeated rotation of the armature in one direction is limited by the flexible electrical leads used for power supply. Nevertheless, a few rotations of the armature, e.g., one or two rotations, may be possible if such a rotation is required in a specific application. The armature must then be rotated back to its initial position. In switching devices, a rotation angle of approximately 60° is preferably used when the rotary actuator is employed as the primary drive of a switch.

[0038] The rotation angle limiting device can be designed by one or more lugs projecting from the armature, which come into contact with a stop (a physical obstacle) arranged on the stator when the armature reaches an end position, thus preventing further rotation of the armature. Alternatively, the rotation angle limiting device can be designed by pawls or springs.

[0039] The invention will now be explained using several exemplary embodiments and the accompanying drawing. Each drawing is schematic and not to scale. Fig. 1 a known linear actuator; Fig. 2 a first embodiment of the rotary actuator according to the invention; Fig. 3 a cut of the anchor from Fig. 2 perpendicular to the axis of rotation; Fig. 4 a section of the stator of Fig. 2 perpendicular to the axis of rotation; Fig. 5 a section of the stator and armature coils of Fig. 2 perpendicular to the axis of rotation; Fig. 6 a circuit diagram of the rotary actuator of Fig. 2; Fig. 7 a cut of the rotary actuator from Fig. 2 with the current directions at a first time; Fig. 8 a cut of the rotary actuator from Fig. 2 with the current directions at a second time; Fig. 9 a time course of the current in the coils and the torque between armature and stator with different current directions of the coils; Fig. 10 a dependence of the achievable torque on the overlap of the coils; Fig. 11 a timing of electrical impulses; Fig. 12 that through the timing of Fig. 11 induced torque; Fig. 13 a section of a rotary actuator with a 3-part division; Fig. 14 a section of a rotary actuator with a 4-part division; Fig. 15 a section of a rotary actuator with a 6-part division; Fig. 16 a second embodiment of the rotary actuator according to the invention; Fig. 17 a third embodiment of the rotary actuator according to the invention; Fig. 18 a view of a short-circuiting device; Fig. 19 an exemplary design of a rotary actuator for a short-circuiting device for arc suppression; Fig. 20 a temporal progression of various quantities with the in Fig. 19 sketched rotary actuators; Fig. 21 an exemplary design of a rotary actuator for a rapid release for arc fault suppression; Fig. 22 a temporal progression of various quantities with the in Fig. 21 sketched rotary actuator; Fig. 23 a circuit breaker with a vacuum switching tube and a rotary actuator, which acts as an auxiliary drive of the circuit breaker; Fig. 24 a circuit breaker with a vacuum switching tube and a rotary actuator acting as a main drive of the circuit breaker; Fig. 25 an oblique view of a rotation angle limiting device; and Fig. 26 a top view of the rotation angle limiting device of Fig. 25.

[0040] Fig. Figure 1 shows a linear actuator comprising a hollow cylindrical stator 10 and a hollow cylindrical armature 20. The armature 20 is located inside the stator 10, where it can be moved linearly back and forth along a motion axis 100 that coincides with the rotation axes of the stator 10 and armature 20. The stator 10 has a circumferential recess (groove) on its inner circumference in which a stator coil 11 is inserted. The armature 20 has a circumferential recess (groove) on its outer circumference in which an armature coil 21 is inserted. By appropriately energizing the coils 11 and 21, a desired linear motion of the armature 20 relative to the stator 10 can be achieved. A similar linear actuator is described, for example, in DE102011080065A1 (MSM Krystall GbR) 19.04.2012.

[0041] Fig. Figure 2 shows a first embodiment of the rotary actuator 1 according to the invention.

[0042] The rotary actuator 1 has a hollow cylindrical stator 10, e.g., made of a metal, which has six longitudinal ribs 12 extending along its axis of rotation 2 on its inner circumference. Three stator coils 11 are wound in the spaces (slots) between the longitudinal ribs 12. The three stator coils 11 are thus connected to the stator 10 in such a way that a force acting on the stator coils 11 is transmitted to the stator 10.

[0043] The rotary actuator 1 has a hollow cylindrical armature 20, e.g. made of a metal, which is arranged inside the stator 10 and which is rotatable about its axis of rotation 2 relative to the stator 10.

[0044] The armature 20 has six longitudinal ribs 22 extending along its axis of rotation 2 on its outer circumference. Three armature coils 21 are wound in the spaces (slots) between the longitudinal ribs 22. The three armature coils 21 are thus connected to the armature 20 in such a way that a force acting on the armature coils 21 is transmitted to the armature 20.

[0045] The rotary actuator 1 can be used to generate a rotary motion of a rotating shaft; for this purpose, the rotating shaft is guided through the armature, along the axis of rotation of the armature, and connected to the armature in a rotationally fixed manner, e.g. by a known tongue-and-groove connection. Thus, a rotation of the armature results in a rotation of the rotating shaft.

[0046] The stator coils 11 and the armature coils 21 are supplied from a voltage source in parallel or series connection because this allows relatively high impulse torques to be generated.

[0047] Fig. Figure 3 shows a section of the armature 20 transverse to the axis of rotation 2. The armature 20 has six longitudinal ribs 22 extending along its axis of rotation 2 on its outer circumference. As is known from the manufacture of electric motors, the armature can be assembled from individual laminations to suppress eddy currents.

[0048] Fig. Figure 4 shows a section of the stator 10 transverse to the axis of rotation 2. The stator 10 has six longitudinal ribs 12 extending along its axis of rotation 2 on its inner circumference. As is known from the manufacture of electric motors, the stator can be assembled from individual laminations to suppress eddy currents.

[0049] Fig. Figure 5 shows a section of the three stator coils 11 and three armature coils 21 perpendicular to the axis of rotation 2. The coils 11, 21 are each wound in the recesses between the longitudinal ribs 12, 22.

[0050] Fig. Figure 6 shows a circuit diagram of a circuit 9 for the rotary actuator 1 of Fig. 2. The rotary actuator 1 of Fig. 2 has a stator 10 and an armature 20, each with three coils.

[0051] In circuit 9, a stator coil 11 and an armature coil 21 are connected in series and electrically connected to a voltage source 50. Thus, the stator coil 11 and the armature coil 21 are energized if a switch 52 connected in circuit 9 is in the conducting state. The voltage source 50 can be designed as an electrical energy storage device 6, e.g., a capacitor, which can discharge its electrical charge into the stator coil 11 and the armature coil 21.

[0052] Circuit 9 comprises power lines 3 through which energize the stator coil 11, and flexible lines 4, e.g., stranded wires, through which energize the armature coil 21. The flexibility of the lines 4 is necessary because the armature 20 is to perform a rotary movement and no sliding contacts are provided.

[0053] A freewheeling path 13 is connected in parallel to the stator coil 11 and the armature coil 21, in which a freewheeling diode D is arranged. During the time intervals in which the switch 52 is closed, the freewheeling diode D carries the inductive current of the coils 11 and 21. This is a standard circuit configuration for inductive loads, in this case the coils 11 and 21, to prevent current interruption and thus overvoltages for the switch 52, e.g., a power semiconductor.

[0054] The rotary actuator also has a control unit 7 that controls the current supply to the stator coil 11 and the armature coil 21 by actuating the switch 52, causing the switch 52 to open (current does not flow) or close (current flows) the circuit 9 at defined times.

[0055] Fig. 7 and Fig. Figure 8 shows a cross-section of the rotary actuator of Fig. Figure 2 shows the current directions at two different times. The current direction is indicated by arrowheads and arrowheads: An arrowhead (dot) indicates that current flows out of the plane of the blade, an arrowhead (cross) indicates that current flows into the plane of the blade. The current directions in the stator 10 are the same at both times, while in the armature 20, the current directions are opposite at the two times. Reversing the polarity of the coils can be done electronically, not with sliding contacts.

[0056] Fig. Figure 9 shows a diagram with arbitrary units along the y-axis and time t in milliseconds along the x-axis. Curves 91 / 92 and 93 / 94 result from different current directions, leading to left-hand and right-hand rotation, respectively. Curve 91 shows the time course of the armature torque M for a first current direction. Curve 92 shows the time course of the current I in the armature coil for the first current direction. Curve 93 shows the time course of the armature torque M for a second current direction opposite to the first. Curve 94 shows the time course of the current I in the armature coil for the second current direction.

[0057] In Fig. Figure 9 shows that a single current pulse 92, 94, at a suitable time, delivers a torque pulse 91, 93. The single current pulse 92, 94 can be triggered by an angle sensor that measures the angular position of the armature relative to the stator. The torque pulse 91, 93 occurs simultaneously and without delay with the current pulse 92, 94. A positive torque pulse 93 can be used in a vacuum tube circuit breaker as an acceleration pulse to influence the contact bounce or for the breakover shock. A negative torque pulse 91 can be used in a vacuum tube circuit breaker as a braking pulse to influence the contact bounce.

[0058] Fig. Figure 10 shows a diagram with torque M in arbitrary units along the y-axis and the rotation angle φ in degrees along the x-axis. The data points represented by stars indicate that a maximum negative torque is reached at a rotation angle of approximately 30 degrees between a stator coil and an armature coil. The data points represented by circles indicate that a maximum positive torque is reached at a rotation angle of approximately 90 degrees between a stator coil and an armature coil. This relationship can be used, for example, in a rotary actuator employed as a main drive in a vacuum tube circuit breaker.

[0059] Fig. Figure 11 shows a diagram with the current I in arbitrary units along the y-axis and the time t in milliseconds along the x-axis. A defined clocking sequence with a period of 5 ms is plotted for the coil current 111 flowing through the stator coils and the coil current 112 flowing through the armature coils. The current 113 through the freewheeling diode D is also plotted. To achieve continuous rotation of the armature, several current pulses are required in succession. The absolute current magnitude is less important than the rate of change of current dI / dt. Therefore, for continuous rotation of the armature, it is more effective to generate several short current pulses than one long-lasting current of a large magnitude.

[0060] Fig. Figure 12 shows a diagram with the torque M in the unit Nm along the y-axis and the time t in the unit milliseconds along the x-axis. Fig. 12 shows this through the timing of Fig. 11 induced torques.

[0061] Fig. Figure 13 shows a section of a rotary actuator with a 3-part division, Fig. 14 a section of a rotary actuator with a 4-part division and Fig. Figure 15 shows a cross-section of a rotary actuator with a stator and armature pitch of 6. By varying the number of stator and armature coils, and thus the number of pole pairs, a rotary actuator can be adapted to different requirements, e.g., torque and rotational speed.

[0062] Fig. Figure 16 shows a second embodiment of the rotary actuator according to the invention. The outer diameter is 60 mm and the length is 75 mm. Fig. Figure 17 shows a third embodiment of the rotary actuator according to the invention. The outer diameter is 75 mm and the length is 50 mm. By varying the dimensions and geometry of the rotary actuator, it can be adapted to different requirements, e.g., torque and rotational speed.

[0063] Fig. Figure 18 shows a view of a short-circuiting device having three insulators 81, 82, 83, each for one of the current phases L1, L2, L3. An electrically conductive connection between the three current phases L1, L2, L3 can be created by rotating a conductive contact bar 84. Without a circuit breaker to de-energize the system when the short-circuiting device is activated, the system remains energized and current continues to flow. The resulting short circuit of the three current phases L1, L2, L3 de-energizes the electrical system connected to the short-circuiting device and prevents more serious damage. The rotation of the contact bar 84 is currently achieved by a slow rotary actuator 85. A similar design could be equipped with a rapidly rotating rotary actuator according to the invention and used as a short-circuiting device for arc suppression.

[0064] Fig. Figure 19 shows an exemplary design of a rotary actuator for a short-circuiting device for arc suppression. The outer diameter is 60 mm and the length is 250 mm. The capacitor used as a voltage source has a capacitance of 8 x 560 µF at a voltage of 360 V.

[0065] Fig. Figure 20 shows a diagram with arbitrary units along the y-axis and time t in milliseconds along the x-axis. Plotted for the in Fig. The 19 sketched rotary actuators are the time course of a voltage 71, a first current 72, a second current 73, a torque 74, one tenth of the angular velocity 75, one hundredth of the rotation angle 76, and one tenth of the angular acceleration 77. The resulting impulse current has a magnitude of 800 A, which can generate a maximum torque of 400 Nm within one millisecond.

[0066] Fig. Figure 21 shows an exemplary design of a rotary actuator for a rapid release for arc fault interruption. The outer diameter is 25 mm and the length 50 mm. The capacitor used as a voltage source has a capacitance of 560 µF at a voltage of 360 V.

[0067] Fig. Figure 22 shows a diagram with arbitrary units along the y-axis and time in milliseconds along the x-axis. Plotted for the in Fig. The 21 sketched rotary actuator is defined by the time course of a voltage 71, a tenth of a first current 72, a tenth of a second current 73, a torque 74, an angular velocity 75, a rotation angle 76, and an angular acceleration 77. The resulting impulse current has a magnitude of 700 A, which can generate a maximum torque M of approximately 25 Nm within approximately 200 microseconds.

[0068] The Fig. 19 with 20 as well as the Fig. Figures 21 and 22 show different embodiments for different torque-time profiles.

[0069] Fig. Figure 23 shows a switch 201 of a vacuum circuit breaker, as described, for example, in the Siemens manual "Instruction Manual, Type 3AH35-MA vacuum circuit breaker magnetic-actuator operator module, Installation operation maintenance", Article No. E50001-F710-K378-V6-4A00, published by Siemens Industry, Inc., Wendell, North Carolina, 27591, USA, 2016. The vacuum circuit breaker is a component of a circuit breaker. The switch 201 has two electrical switching contacts 204, 205, namely a fixed contact 204 and a moving contact 205, which are arranged in an evacuated switching chamber of the vacuum circuit breaker (not shown). The switching contacts 204, 205 are designed as pressure contacts, i.e., to form a current-carrying contact between the switching contacts 204, 205, the switching contacts 204, 205 are pressed against each other.The fixed contact 204 is located at one end of a fixed contact rod 206, and the moving contact 205 is located at one end of a moving contact rod 207, which is slidably guided, vacuum-sealed by means of a metal bellows (not shown), and led out of the switching chamber of the vacuum switching tube through a cover (not shown). By means of the moving contact rod 207, the moving contact 205 can be brought into galvanic contact with the fixed contact 204 in a closing operation and, in an opening operation, separated from the fixed contact 204 to such an extent that a sufficient safety distance exists between the two contacts 204 and 205 to prevent arcing. The distance between the contacts 204 and 205 must be large enough that the arc extinguishes at the current zero crossing and does not reignite when the voltage rises again.

[0070] The axial movement of the moving contact rod 207 is effected by a magnetic drive 203 serving as the main drive of the vacuum switching tube, by adjusting an armature 224 of the magnetic drive 203, designed as a diving armature, between two end positions through interaction with a permanent magnet PM and a magnetic coil EM of the magnetic drive 203: for this purpose, an axial movement of the armature 224 is redirected into an axial movement of the moving contact rod 207 by means of a transmission gear 202. Fig. Figure 23 shows that a second end position of the armature 224 corresponds to an open contact position of the switching contacts 204, 205.

[0071] The transmission mechanism 202 has an angled three-joint link 218, which is connected to the moving contact rod 207 via a first joint 211. The three-joint link 218, which is rotatably mounted in a second joint 212, is connected to a connecting rod 219 via a third joint 213. The connecting rod 219, in the manner of a telescopic tube, has an outer tube and an inner tube axially displaceable within the outer tube. The axial displacement of these tubes relative to each other is effected by a contact compression spring 208, which is designed as a coil spring clamped between two spring support elements formed on the outer and inner tubes, respectively. Connecting rods of this type are found as spring elements, for example, in the automotive sector.

[0072] Switches with pressure contacts, which include vacuum switches in particular, require a contact spring that constantly maintains the pressure necessary for current flow between the contacts—the so-called contact force—when the switch is in the closed state (contacts closed). The contact force is generated when the kinematic chain reaches its end position due to the compression of the contact spring. The contact spring is located at a suitable point within the mechanism responsible for transmitting the drive forces to the contacts and has a preload designed so that its spring characteristic, along with its travel, generates the required contact force. During the switch-on process, this preload is overcome when the pressure contacts make contact, resulting in a steep rise in the force-displacement curve of the drive mechanism.Following the overcoming of the preload of the contact compression spring, it is further tensioned by the so-called stroke, so that the desired or required contact force is still present even if the contacts wear out or burn-off occurs.

[0073] The connecting rod 219 is connected via a fourth joint 214 to a lever link 220, which is fixed against rotation on a pivot shaft 209 rotatably mounted in a fifth joint 215; the fifth joint 215, which serves as the bearing point for the pivot shaft 209, is also simply referred to as a bearing. The lever link 220 is further connected via a sixth joint 216 to a connecting rod 221, which in turn is connected via a seventh joint 217 to a drive rod 222. The drive rod 222 itself is fixed to the armature 224.

[0074] In addition to the magnetic drive 203, which serves as the main drive and acts on the rotary shaft 209 via the connecting rod 221 and the lever link 220, the circuit breaker also has a rotary actuator 1 according to the invention, which functions as an auxiliary drive of the circuit breaker. The armature of the rotary actuator 1 is arranged non-rotatably on and coaxially with the rotary shaft 209.

[0075] The vacuum switching unit has one switch 201 each for the three phases L1, L2, L3 of a three-phase line current, whereby, for the sake of simplicity, only the switch 201 of one of the three phases L1, L2, L3 is shown. Fig. Figure 23 shows that all three moving contacts 205 of the vacuum switching unit are actuated together by the magnetic drive 203. For this purpose, the rotating shaft 209 carries three lever links 220, of which, for the sake of simplicity, only a single lever link 220 is shown in Figure 23. Fig. Figure 23 illustrates this. Each of the three lever elements 220 actuates the moving contact 205 of the contact pair 204, 205 of one of the three switches 201 of the vacuum switching unit; thus, the three switches 201 of the vacuum switching unit open and close simultaneously. Simultaneous opening and closing of the switching contacts is the "usual" case; however, there is also the application of phase-selective switching using separate drives, in which case the switching of the three phases occurs at different times. The invention can, of course, also be implemented with such a phase-selective switch.

[0076] For the sake of completeness, it should be noted that there are also single-pole drives in which not all three moving contacts of the vacuum switching unit are actuated by a common magnetic drive, but in which each phase has a separate drive and a separate kinematic chain. Single-phase and two-phase switching devices also exist. The invention can, of course, also be implemented with such a single-pole drive, a single-phase or a two-phase switching device.

[0077] Fig. Figure 24 shows a circuit breaker with at least one vacuum switching tube 1, which has a rotary actuator 1 according to the invention. The in Fig. The circuit breaker shown in the 24 section differs from the one in the... Fig. The circuit breaker shown in Figure 23 is characterized in that the rotary actuator 1 acts as a main drive of the circuit breaker and that a movement of the moving contact 205 of the vacuum switching tube 1 is caused by a rotation of the rotary actuator 1. The Fig. 23 drawn magnetic drive 203 is at the in Fig. The circuit breaker shown in section 24 is not present.

[0078] Fig. Figure 25 shows an oblique view of a rotation angle limiting device 5 of a rotary actuator 1, which has a hollow cylindrical stator 10 and a hollow cylindrical armature 20. On an end face of the rotary actuator 1, the stator 10 has two stop lugs (stops) 61, 63, which are fixed to the end face of the stator 10. On the same end face of the rotary actuator 1, the armature 20 has a lug (stop) 62, which is fixed to the end face of the armature 20. The rotation range of the armature 20 about the axis of rotation 2 is limited by the stop lugs 61, 63 of the stator 10: Rotation in a first direction 25 is limited by the lug 62 of the armature 20 striking the first stop lug 61 of the stator 10; A rotation in a second direction 26 is limited by the nose 62 of the armature 20 striking the second stop nose 63 of the stator 10.

[0079] Fig. 26 shows the in Fig.Figure 25 shows a top view of the rotation angle limiting device 5 of the rotary actuator 1. The position shown is that when the nose 62 of the armature 20 abuts the first stop nose 61 of the stator 10. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102011080065A1

[0040] Cited non-patent literature

[0000] Siemens Handbuch „Instruction Manual, Type 3AH35-MA vacuum circuit breaker magnetic-actuator operator module, Installation operation maintenance“, Article No. E50001-F710-K378-V6-4A00, Published by Siemens Industry, Inc., Wendell, North Carolina, 27591, USA, 2016

[0069]

Claims

[1] Rotary actuator (1), comprising: - a stator (10), - at least one stator coil (11) connected to the stator (10) such that a force acting on the stator coil (11) is transmitted to the stator (10); - an armature (20) rotatable about an axis of rotation (2) relative to the stator (10), - at least one armature coil (21) connected to the armature (20) in such a way that a force acting on the armature coil (21) is transmitted to the armature (20); - electrical lines (3) through which at least one stator coil (11) can be supplied with current, and - electrical lines (4) through which the at least one armature coil (21) can be supplied with current. [2] Rotary actuator according to claim 1, wherein the at least one stator coil (11) and the at least one armature coil (21) are connected in series. [3] Rotary actuator according to one of the preceding claims, wherein the number of pole pairs of the armature (20) and the stator (10) are the same. [4] Rotary actuator according to one of the preceding claims, comprising an electrical energy storage device (6) which can discharge its charge into the at least one stator coil (11) and / or at least one armature coil (21). [5] Rotary actuator according to one of the preceding claims, comprising a control unit (7) which controls the energization of the at least one stator coil (11) and the at least one armature coil (21). [6] Rotary actuator according to claim 5, wherein the control unit (7) is arranged to control an electronic reversal of the coils (11, 21). [7] Rotary actuator according to one of the preceding claims, wherein the at least one stator coil (11) and the at least one armature coil (21) overlap radially. [8] Rotary actuator according to one of the preceding claims, comprising a rotation angle limiting device (5) by which a rotation (25, 26) of the armature (20) relative to the stator (10) is limited to a defined rotation angle range. [9] Method for operating the rotary actuator according to any one of claims 1 to 8, wherein a current pulse triggered by an angular position (φ) of the armature (20) relative to the stator (10) causes a braking or acceleration pulse. [10] Method according to claim 9, wherein several current pulses in succession cause a continuous movement of the armature (20). [11] A method according to any one of claims 9 or 10, wherein the one or more current pulses cause a current change dI / dt. [12] Method according to one of claims 9 to 11, wherein in an initial position a first stator coil (11) and an armature coil (21) overlap, a current pulse is triggered which causes a movement of the armature (20) so that the overlap of the first stator coil (11) and the armature coil (21) increases and a further current pulse is triggered when the overlap of the first stator coil (11) and armature coil (21) has decreased again. [13] Switching device with at least one switch (201), comprising a rotary shaft (209) and a main drive (203) acting on the rotary shaft (209), wherein a movement of a moving contact (205) of the at least one switch (201) is caused by a rotation of the rotary shaft (209), further comprising a rotary actuator (1) according to one of claims 1 to 8, wherein the rotary actuator (1) functions as an additional drive of the switch (201) and the armature (20) of the rotary actuator (1) is arranged in a rotationally fixed manner on and coaxial with the rotary shaft (209). [14] Switching device with at least one switch (201), comprising a rotary actuator (1) according to one of claims 1 to 8, wherein the rotary actuator (1) acts as a main drive of the switch (201) and wherein a movement of a moving contact (205) of the at least one switch (201) is caused by a rotation of the rotary actuator (1). [15] Short-circuiter, comprising a rotary actuator (1) according to one of claims 1 to 8, wherein a movement of a closing contact of the short-circuiter is caused by the rotary actuator (1).

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