Power switch

Abstract

The invention relates to a power switch (1), in particular a high-voltage power switch, comprising at least one electric contact (3), which is made of a movable contact element (7) and another contact element (9), and a drive (11), the drive movement of which can be transmitted, via a kinematic chain (13), to the movable contact element (7) in order to switch the contact (3). The invention is characterized in that at least one flywheel (27) with a controllable moment of inertia is coupled to the kinematic chain (13).

Description

[0001] Description

[0002] Circuit breaker

[0003] The invention relates to a circuit breaker, for example a high-voltage circuit breaker.

[0004] For both the electrical switching capacity and the mechanical durability or service life of an electrical switching device, in particular a circuit breaker, it may be necessary to achieve a certain speed characteristic when switching the circuit breaker.

[0005] For example, for a circuit breaker with vacuum tubes and switching contacts, such as plate contacts, it is necessary to limit the closing speed at the time of contact between the switching contacts to a certain value in order to avoid mechanical damage to the switching contacts or to load them to such an extent that only individual particles are released and, as a result, the electrical switching capability of the circuit breaker is not impaired.

[0006] The invention is based on the object of providing a circuit breaker with improved switching behavior.

[0007] The object is achieved according to the invention by a circuit breaker having the features of patent claim 1.

[0008] Advantageous embodiments of the invention are the subject of the dependent claims.

[0009] The circuit breaker according to the invention, in particular a high-voltage circuit breaker, comprises at least one electrical contact, formed by a movable contact element and a further contact element, in particular a fixed contact element or a further movable contact element, and a drive, the drive movement of which can be transmitted via elements of a kinematic chain to the movable contact element for switching the contact, wherein at least one flywheel is coupled or connected to the kinematic chain or into the kinematic chain, the moment of inertia of which flywheel is controllable.

[0010] The electrical contact of the circuit breaker can, for example, comprise several parallel-connected contact pairs of two contact elements, for example, one contact pair optimized for transmitting the rated current and one contact pair optimized for a short-circuit current. A contact pair, for example, comprises a fixed contact element and a movable contact element. Alternatively, it is also possible to move both contact elements during the switching movement.

[0011] In particular, the circuit breaker can comprise several contacts connected in series, with each contact pair then only having to hold a portion of the voltage. All contacts can be opened and closed by a single drive, but it is also possible for each contact to be opened and closed by its own drive.

[0012] A flywheel (also referred to as a flywheel mass, flywheel disc, or flywheel body) is understood to be a machine or drive element that functions as an energy storage device for storing kinetic energy, particularly rotational energy, for example, by storing its rotational movement with the lowest possible friction loss. The flywheel can be disc-shaped.

[0013] The moment of inertia (also called mass moment of inertia or inertial moment) is the inertia of a rigid body with respect to a change in its angular velocity when rotating about a given axis. The moment of inertia is a measure of the resistance that a rigid body offers to a change in its angular velocity.

[0014] A kinematic chain is understood to mean, in particular, elements or links of a transmission, such as transmission elements, joints, links, levers or the like, via which the drive movement of a drive, such as a motor or a spring-loaded drive, can be transmitted to the movable contact element.

[0015] The advantages achieved by the invention lie, in particular, in the fact that the inertia of the kinematic chain can be increased by a coupled flywheel with a specific moment of inertia and can also be variably controlled. This allows the switching speed of the circuit breaker to be variably controlled. For example, during closing, the kinetic energy required at the end of a closing movement to tension an opening spring or contact pressure spring after the switching contacts come together can be temporarily stored without exceeding a specific closing speed upon contact.

[0016] The moment of inertia of the flywheel can be varied, for example, by radially movable mass elements arranged on the flywheel. It is advantageous to use at least two evenly distributed mass elements to avoid imbalance. Alternatively, it is possible to use only one adjustable mass element.

[0017] In one possible embodiment, the flywheel can be configured such that the moment of inertia of the flywheel can be changed depending on a position, in particular a switching position of the circuit breaker, in particular its movable contact element. Such a

[0018] REVISED SHEET (RULE 91) ISA / EP equipped flywheel, the moment of inertia of which can be varied as a function of the position, allows, for example, both damping and an increase in the switching speed in a simple manner.

[0019] For example, the flywheel can be configured in such a way that a switching speed of the movable contact element can be controlled in certain areas.

[0020] For example, when the contact elements are switched off or separated, the flywheel can be configured to provide a high switching-off speed for separating the contact elements in a first travel range and / or time range. In particular, the flywheel can be adjusted or configured such that the moment of inertia is small.

[0021] In a second travel range and / or time range, the flywheel can provide a lower cut-out speed and thus a delay or damping of the cut-out speed. In particular, the flywheel can be adjustable or configured such that the moment of inertia is large and absorbs and stores a large amount of kinetic energy.

[0022] According to a further embodiment, the flywheel can be configured to increase the moment of inertia starting at a predetermined, particularly high, angular velocity. The flywheel can additionally be configured to limit the shifting speed to a predetermined value. The flywheel can also be configured to reduce the moment of inertia at a predetermined, particularly low / lower, angular velocity. This can shorten an acceleration phase or accelerate the shifting movement.

[0023] In one possible embodiment, the flywheel is provided with a number of movable mass elements. For example, at least one mass element can be provided that is arranged radially movable on the flywheel. Preferably, at least two mass elements are arranged evenly distributed on the flywheel. In other words, the flywheel can be designed as a dual-mass flywheel or a four-mass flywheel or the like.

[0024] A further embodiment provides that the flywheel is provided with a control element which is designed to guide the at least one mass element in a radially movable manner. For example, the mass elements can be arranged on the flywheel in a radially movable manner and this movement can additionally be limited radially outwards by return springs. This ensures that the mass elements are displaced radially outwards by the centrifugal force when the centrifugal force becomes greater than the spring force due to the increasing angular velocity. As a result, the mass moment of inertia increases above a certain angular velocity. The switching speed can be limited to a certain level by the return springs.In addition, the mass moment of inertia can be reduced at lower angular velocities and thus be smaller, for example to shorten the acceleration phase or to accelerate the switching movement compared to a known constant high mass moment of inertia.

[0025] In a further example, the control element can be passive, for example as a guide track, a curved track or the like, on the flywheel. Alternatively, the control element can be active, as a hydraulic actuating element or an electromagnetic actuating element or a spring actuating element. By radially displacing the mass element(s), for example actively by means of a hydraulic actuating element or an electromagnetic actuating element, a displacement is possible depending on the position of the flywheel and additionally optionally on the time and / or the direction of movement. Alternatively, the radial displacement of the mass elements can be controlled by a fixed curved track in one or both radial directions. In this way, a specific moment of inertia can also be achieved depending on the position.In other words: The mass elements, which are movably arranged on the circumferentially rotating flywheel during a shifting movement, can be displaced radially in both directions, for example, by a fixed cam track. The cam track can be configured such that the moment of inertia of the flywheel changes depending on the position and the shifting speed is variably controlled over a specific distance.

[0026] A further development provides that the control element is configured such that the at least one mass element is movably guided in at least one or both radial directions. This allows a specific moment of inertia to be provided depending on the position.

[0027] In addition, a limiter, for example, a return spring, can be provided to limit the radial movement of the at least one mass element. By displacing the mass elements by centrifugal force against a force, for example, of a return spring, it is possible to achieve a dependence of the moment of inertia on the angular velocity.

[0028] A further embodiment provides for an outward adjustment of the mass elements by a combination of passive and active control elements, in particular a combination of a cam track with a hydraulic actuating element or an electromagnetic actuating element and a return by a return spring.

[0029] In one possible embodiment, the drive can be designed as a spring-loaded drive. The flywheel can, for example, be arranged in the kinematic chain on a tensioning shaft of a closing spring of the spring-loaded drive. This ensures that the flywheel has no influence on the required higher breaking speed. Alternatively, the flywheel can be arranged on a switching shaft of a breaking spring or a gear shaft.

[0030] The flywheel can be rigidly or non-rotatably attached to the tensioning shaft, the selector shaft, or the transmission shaft. Alternatively, a driver for the flywheel can be provided with a freewheel. For example, the flywheel can be driven in only one direction using a freewheel. Drive can also be achieved via a gearbox, for example, to achieve a higher angular velocity of the flywheel.

[0031] In a further embodiment, the flywheel can be coupled or can be coupled via a gear element. This allows a different angular velocity and thus a different switching speed than that of the tensioning shaft or switching shaft to be achieved.

[0032] In summary, the invention enables a controllable variable moment of inertia of a flywheel coupled to the kinematic chain of the circuit breaker with radially movable mass elements.

[0033] By means of a variable and controllable moment of inertia of the flywheel, the switching speed can be reduced as required, for example in a certain time or distance interval before the switching contacts meet, by significantly increasing the mass inertia of the flywheel in the corresponding interval, without the maximum required moment of inertia of the flywheel delaying the switching movement, for example in the acceleration phase at the beginning of the switching movement and thus extending the overall switching time. In a particularly simple embodiment of the invention with centrifugal force adjustment of the mass elements against a spring force, the maximum switching speed can be limited without the high moment of inertia of the flywheel delaying the switching movement, for example in the acceleration phase at the beginning of the switching movement, and thus extending the overall switching time.

[0034] If the breaking speed needs to be reduced in a second travel or time interval following an initial interval with a very high switching speed after contact separation, a flywheel with a variable moment of inertia can also be used to great advantage. Compared to the hydraulic damper previously used for this purpose, the new solution has the advantage that the switching energy is not lost for the switching movement and remains available after the delayed interval, for example, to reliably reach the end position even if the opposing forces increase again. By adjusting the flywheel again, the switching speed can be controlled and influenced again.

[0035] The invention also allows for setting different mass moments of inertia for an on-off movement, for example, if the displacement of the mass elements is achieved by passive and / or active control elements. This makes it possible to arrange the flywheel at an alternative location in the kinematic chain.

[0036] In contrast, when the closing spring is arranged on the tensioning shaft, it is only possible to influence the closing movement, but not the opening movement.

[0037] Alternatively, it is possible to arrange the flywheel on a shaft that rotates when the circuit breaker is closed and opened. The flywheel and the mass elements can be configured and interact in such a way that different moments of inertia can be set depending on the switching movement—closing movement or opening movement. The flywheel and the mass elements can also be configured and interact in such a way that the moment of inertia can be controlled, in particular changed, during a switching movement.

[0038] The invention makes it possible, for example, through the controllable moment of inertia of the flywheel, to reduce the making speed and / or breaking speed without exceeding a certain value. If in this case, after the contact elements have come into contact at the end of the making movement, for example contact pressure springs or a spring for providing the breaking energy still have to be tensioned, the invention, in particular the flywheel with the radially movable mass elements, makes it possible for the energy provided by the making spring to be temporarily stored at the beginning of the switching movement in the form of kinetic energy of the flywheel, in order to then release this energy at the end of the switching movement to the contact pressure springs or breaking spring for tensioning and providing the breaking energy.

[0039] Depending on the mass inertia of the flywheel, a certain speed is required for the flywheel as a component of the kinematic chain in order to temporarily store a certain kinetic energy. The flywheel can therefore preferably be designed to temporarily store the energy required for the opening movement of the circuit breaker and at the same time achieve a certain speed profile. It may also be necessary, for example in circuit breakers with vacuum tubes, for the flywheel to provide a certain high contact speed in a certain time interval or in a certain travel interval after the contact elements have separated and then to limit the contact speed to a significantly lower level during a second interval.The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following description of exemplary embodiments, which are explained in more detail in conjunction with the drawings.

[0040] FIG 1 shows a schematic partial sectional view of a circuit breaker with a flywheel,

[0041] FIG 2 shows a schematic representation of an example of a flywheel with mass elements,

[0042] FIG 3 shows a schematic representation of another example of a flywheel with mass elements, and

[0043] FIG 4 shows a schematic representation of another example of a flywheel with mass elements.

[0044] Corresponding parts in the figures are provided with the same reference symbols.

[0045] Although the invention has been illustrated and described in detail by means of preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

[0046] Figure 1 shows a schematic, partially sectional view of a circuit breaker 1 .

[0047] By way of example, a high-voltage circuit breaker is shown as a circuit breaker 1 (also called switchgear or switching device). The circuit breaker 1 comprises an electrical contact 3, shown in a housing 5. The electrical contact 3 comprises, for example, a movable contact element 7 and a further contact element 9. The further contact element 9 can, for example, be movable or fixed. The contact elements 7, 9 are made of, for example, copper, graphite and / or steel.

[0048] Furthermore, the circuit breaker 1 comprises a drive 11, the drive movement of which can be transmitted via a kinematic chain 13 to the movable contact element 7 for switching the contact 3.

[0049] When the circuit breaker 1 is switched on, in particular when the contact 3 is closed, the movable contact element 7 is moved towards the further contact element 9 until a mechanical and electrical coupling or connection is established.

[0050] When the circuit breaker 1 is switched off, the movable contact element 7 is moved away from the other contact element 9 until the electrical contact 3 is opened.

[0051] The drive 11, for example a motor and / or a spring-loaded drive 31, provides the necessary kinetic energy for switching. Elements of the kinematic chain 13, for example gear elements 15, such as a gear shaft 15.1, a drive rod 17, a tension shaft 19 and / or a switching shaft 20, transmit the drive movement from the drive 11 to the movable contact element 7.

[0052] A closing spring 21 can be tensioned via the tensioning shaft 19 of the spring-loaded mechanism 31. During switching on, the relaxing closing spring 21 tensions an opening spring 23 and a contact pressure spring 22 via elements not shown in the spring-loaded mechanism 31 and switches on the contact 3 by actuating the movable contact element 7. During switching on, both the tensioning shaft 19 and the switching shaft 20 and the gear shaft 15 rotate. 1.

[0053] When switching off, the switching-off spring 23 relaxes and the contact pressure spring 22 and the contact elements 7, 9 are separated and opened via the kinematic chain 13.

[0054] The tensioning shaft 19 is not rotated during switching off; only the switching shaft 20 and the gear shaft 15 . 1 are rotated by the relaxing switching off spring and contact pressure spring 22 .

[0055] The flywheel 27, when arranged on the tensioning shaft 19, can control and influence the activation of the electrical contact 3. Alternatively, the flywheel 27, when arranged on the selector shaft 20 or the transmission shaft 15, can control and influence both the activation and deactivation of the electrical contact 3.

[0056] The electrical contact 3 is arranged in the housing 5. The housing 5 is, for example, a ribbed insulator made of a composite material, ceramic and / or silicone.

[0057] The housing 5 can be provided with an insulator 25, for example filled with a switching or insulating gas, e.g. SF6 and / or clean air, or with another suitable insulator material in order to obtain good electrical insulation between the contact elements 7, 9 and across the inside of the housing when the circuit breaker 1 is in the open state.

[0058] For variable adjustment of the switching speed, at least one flywheel 27, whose moment of inertia is controllable, is coupled to or connected into the kinematic chain 13. The flywheel 27 is designed as an energy storage device for storing kinetic energy, in particular rotational energy.

[0059] Because the mass inertia of the kinematic chain 13 can be increased by the coupled flywheel 27 with a specific moment of inertia and can also be variably controlled, the switching speed, in particular the closing speed and / or the opening speed, of the circuit breaker 1 can be variably controlled.

[0060] For example, during switching on, a kinetic energy required after the contact elements 7, 9 come together and at the end of a switching-on movement to tension the opening spring 23 or the contact pressure spring 22, which only acts after a galvanic contact of the contact elements 7, 9, can be temporarily stored by means of the flywheel 27, without exceeding a certain switching-on speed when the contact elements 7, 9 come together.

[0061] For example, the flywheel 27 can be configured such that its moment of inertia can be varied depending on a position of the flywheel 27 and / or a switching position of the circuit breaker 1, in particular of the movable contact element 7. A flywheel 27 configured in this way, whose moment of inertia can be varied depending on the position, enables, for example, both a damping and an increase in the switching speed in a simple manner.

[0062] For example, the flywheel 27 can be configured such that a switching speed of the movable contact element 7 can be controlled in certain areas.

[0063] Furthermore, the flywheel 27 can be configured to provide a high switching-off speed for separating the contact elements 7, 9 when the contact elements 7, 9 are switched off or separated in a first travel range and / or time range by configuring the flywheel 27 such that its moment of inertia is small, and to provide a lower switching-off speed and thus a delay or damping of the switching-off speed in a second travel range and / or time range by configuring the flywheel 27 such that its moment of inertia is large and absorbs and stores kinetic energy.

[0064] The flywheel 27 can also be configured to increase the moment of inertia starting from a predetermined, in particular high, angular velocity. The flywheel 27 can additionally be configured to limit the switching speed to a predetermined value. Furthermore, the flywheel 27 can be configured to reduce the moment of inertia at a predetermined, in particular low / lower, angular velocity. This can shorten an acceleration phase.

[0065] The flywheel 27 can, for example, be arranged in the kinematic chain 13 on the tensioning shaft 19 of a closing spring 21 or the switching shaft 20 of a breaking spring 23 or the gear shaft 15.1 of the drive 11 designed as a spring-loaded drive 31. If the flywheel 27 is only arranged on the tensioning shaft 19, it is ensured that the flywheel 27 has no influence on the required higher breaking speed, but only on the closing speed. If, on the other hand, the flywheel 27 is arranged on the switching shaft 20 or the gear shaft 15.1, both the closing speed and the breaking speed can be controlled by means of the flywheel 27.

[0066] The flywheel 27 can, for example, be rigidly or non-rotatably attached to the tensioning shaft 19 or the switching shaft 20 or the gear shaft 15. 1. As a result, the flywheel 27 is rotated according to arrow 10 both when the circuit breaker 1 is switched on and off. Alternatively, a driver for the flywheel 27 with a freewheel can be provided. For example, the flywheel 27 can be driven in only one direction by using a freewheel. The drive can also be achieved via a gear, for example to achieve a higher angular speed of the flywheel 27.

[0067] Figure 2 shows a schematic representation of an example of a flywheel 27. The flywheel 27 can be disc-shaped. The flywheel 27 has a through-opening 28 for receiving the tensioning shaft 19 or another shaft in the kinematic chain 13.

[0068] In one possible embodiment, the flywheel 27 is provided with a number of movable mass elements 35. The moment of inertia of the flywheel 27 can be varied, for example, by means of mass elements 35 that are radially movable on the flywheel 27.

[0069] Advantageously, at least two evenly distributed mass elements 35 are provided to prevent imbalance. Alternatively, it is possible to use only one adjustable mass element 35. Alternatively, the number of mass elements 35 can be a multiple of two or, in the case of an odd number of mass elements 35, can be evenly distributed. In other words, the flywheel 27 can be designed as a two-mass flywheel, a three-mass flywheel, a four-mass flywheel, a five-mass flywheel, or a six-mass flywheel, or the like.

[0070] Furthermore, the flywheel 27 can be provided with a control element 37 which is designed to guide the at least one mass element 35 in a radially movable manner. In Figure 2, the control element 37 is, for example, passive. For example, the control element 37 is designed as a guide track 39 or a curved track or the like on the flywheel 27. The radial displacement of the mass elements 35 can be controlled by the fixed guide track 39 in one or both radial directions. For example, the guide track 39 is designed as a cam track along which the two mass elements 35 can be moved radially outwards and / or radially inwards. As a result, a specific moment of inertia can be achieved depending on the position of the flywheel 27. As a result, the switching speed can in turn be variably controlled over a specific distance.

[0071] In addition, the mass elements 35 can be guided radially movably on the flywheel 27 by means of the guide track 39 and, in addition, their movement radially outwards can be limited by a respective associated limiter 41, in particular a return spring or a return element or a stop. This ensures that the mass elements 35 are, on the one hand, displaced radially outwards by the centrifugal force when the centrifugal force becomes greater than the spring force due to the increasing angular velocity and, on the other hand, are stopped at the same time. As a result, the mass moment of inertia increases above a certain angular velocity. By displacing the mass elements 35 due to centrifugal force against a force of the limiter 41, it is possible to make the moment of inertia dependent on the angular velocity. The limiters 41 can also be used to limit the switching speed to a certain level.In particular, the limiters 41 can prevent the moment of inertia from increasing beyond a certain value, so that the respective switching speed is not reduced any further.

[0072] The guide track 39 can be configured such that the at least one mass element 35 is movably guided in at least one or both radial directions (as shown). Furthermore, the guide track 39 can be configured such that the moment of inertia of the flywheel 27 is reduced at lower angular velocities and thus becomes smaller, for example, to shorten the acceleration phase.

[0073] Figure 3 shows a schematic representation of another example of a flywheel 27 with four mass elements 35'. The difference compared to the mass elements 35 in Figure 2 is that the mass elements 35' are rotatably mounted on the flywheel 37.

[0074] For this purpose, the control element 37 can, for example, be designed to be active. For example, the control element 37 can be designed as an electrical actuating element 43, in particular a rotary drive. Alternatively, the control element 37 can be designed as an active element by a hydraulic actuating element, an electromagnetic actuating element, or a spring actuating element.

[0075] In a further embodiment, the mass elements 35' themselves can be configured such that they automatically move radially outward and radially inward due to the rotational movement of the flywheel 27. The flywheel 27 is designed as a variable flywheel mass and variable inertial mass by the automatically radially moving mass elements 35'.

[0076] By means of a radial displacement of the mass element(s) 35', for example actively by means of the electrical actuating element 43, a displacement is possible depending on the position of the flywheel 27 and additionally optionally on the time and / or the direction of movement.

[0077] Figure 4 shows a schematic representation of another example of a flywheel 27 with mass elements 35 '' .

[0078] This example involves adjusting the

[0079] Mass elements 35 '' outwards by means of a combination of passive and active control elements 37, in particular a combination of a guide track 39 with an electrical actuating element 43. In summary, the circuit breaker 1 has a variable flywheel mass and variable inertial mass by means of the flywheel 27 and the mass elements 35, 35 ' or 35 '' which are radially movable thereon, and in a simple manner enables the inertial mass to be increased and / or reduced in certain areas, so that the switching speed can be varied and / or energy can be stored for tensioning a return element.

Claims

Patent claims 1. Circuit breaker (1), in particular high-voltage circuit breaker, comprising at least one electrical contact (3), formed by a movable contact element (7) and a further contact element (9), and a drive (11), the drive movement of which can be transmitted via a kinematic chain (13) to the movable contact element (7) for switching the contact (3), characterized in that at least one flywheel (27) is coupled to the kinematic chain (13), the moment of inertia of which flywheel is controllable.

2. Circuit breaker (1) according to claim 1, characterized in that the flywheel (27) is arranged such that a moment of inertia of the flywheel (27) can be changed depending on a position of the flywheel (27).

3. Circuit breaker (1) according to claim 1 or 2, characterized in that the flywheel (27) is arranged such that a switching speed of the movable contact element (7) can be controlled in certain areas.

4. Circuit breaker (1) according to one of the preceding claims, characterized in that the flywheel (27) is designed to increase the moment of inertia from a predetermined angular velocity.

5. Circuit breaker (1) according to one of the preceding claims, characterized in that the flywheel (27) is provided with a number of movable mass elements (35, 35', 35'').

6. Circuit breaker (1) according to claim 5, characterized in that the at least one mass element (35, 35' 35'') is arranged radially movable on the flywheel (27).

7. Circuit breaker (1) according to claim 5 or 6, characterized in that at least two mass elements (35, 35' 35'') are arranged uniformly distributed on the flywheel (27).

8. Circuit breaker (1) according to one of the preceding claims 5 to 7, characterized in that the flywheel (27) is provided with a control element (37) which is designed to guide the at least one mass element (35, 35' 35'') in a radially movable manner.

9. Circuit breaker (1) according to claim 8, characterized in that the control element (37) is arranged such that the at least one mass element (35, 35' 35'') is guided so as to be movable in at least one or both radial directions.

10. Circuit breaker (1) according to one of the preceding claims 5 to 9, characterized in that a limiter (41) is provided for limiting the radial movement of the at least one mass element (35, 35' 35'').

11. Circuit breaker (1) according to one of the preceding claims, characterized in that the drive (11) is designed as a spring-loaded drive (31), a motor or a combination thereof.

12. Circuit breaker (1) according to one of the preceding claims, characterized in that the flywheel (27) can only be driven in one direction of rotation.

13. Circuit breaker (1) according to claim 11 or 12, characterized in that the flywheel (27) is arranged on a tensioning shaft (19) or switching shaft (20) or a gear shaft (15.1) of the spring-loaded drive (31).

14. Circuit breaker (1) according to claim 13, characterized in that the flywheel (27) is rigidly attached to the tensioning shaft (19) or the switching shaft (20) or the gear shaft (15.1).

15. Circuit breaker (1) according to one of the preceding claims, characterized in that the flywheel (27) is or can be coupled via a gear.

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