On-load tap changer

Abstract

The invention relates to a load tap changer (10) for switching over between winding taps (N1,..., N J ,..., N N ) of a regulatable transformer (1) without interruption, comprising at least one selector unit (30) for preselecting to a selected winding tap (N J ) without power, at least one load switching unit (40) for actually load switching from a previous winding tap (N J _i) to the preselected winding tap (N J ), at least one gear mechanism (50) with a first gear wheel (31) and a second gear wheel (41), wherein the first gear wheel (31) is assigned to the selector unit (30) and the second gear wheel (41) is assigned to the load switching unit (40), a drive shaft (60) which is actuated by a motor drive (70), the first gear wheel (31) and the second gear wheel (41) are directly in mechanical action connection with each other, so that the gear wheels (31, 41) can be actuated simultaneously, the drive shaft (60) can drive the first gear wheel (31) or the second gear wheel (41).

Description

Technical Field

[0001] The present invention relates to an on-load tap changer for uninterrupted load switching between different winding taps of an adjustable transformer. Background Technology

[0002] Known on-load tap changers typically consist of a selector for pre-selecting the appropriate winding tap to which the transformer should be switched when there is no power load, and a load transfer switch for actually switching the load from the previous winding tap to the pre-selected new winding tap. The switching is performed mechanically by actuating the different switches and contacts of the selector and load transfer switch, the actuation being initiated by a motor drive and drive shaft. Furthermore, it is known from the prior art that the switch cabinet containing the on-load tap changer, along with the motor drive and motor control unit, is externally mounted onto the transformer housing (the so-called "mounted switch").

[0003] GB1114868A discloses a three-phase on-load tap changer in a container, the container being laterally mounted on the wall of an oil boiler of a transformer. The on-load tap changer includes a selector and a load transfer switch with two vacuum switches. The selector pre-selects the transformer winding taps without power using movable selector contacts, and the vacuum switches perform the actual load transfer. The selector and the load transfer switch's individual switching and contact elements are operated via a gear transmission mechanism.

[0004] In on-load tap changers in operation, replacement may be necessary, for example, due to changes in requirements or after ten years of operation and associated aging. When replacing an old on-load tap changer with a new one, in addition to the technical requirements of the tap changer, attention must be paid to the given conditions of the usage location, especially the given space, as on-load tap changers typically have only limited or defined spaces available for their use.

[0005] If a new transformer is equipped with an on-load tap changer, the on-load tap changer is typically first installed on the transformer, and then the transformer, along with the on-load tap changer, is transported to the point of use or to the end customer. This transport is, for example, carried out in a railcar or truck, thus limiting the space available for the transformer, including the on-load tap changer and its associated motor drive, along with the switchgear. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide an improved design for an on-load tap changer that can be mounted on a transformer in a space-saving manner and can be readily adapted to given space conditions.

[0007] The on-load tap changer according to the invention includes an on-load tap changer for uninterrupted switching between winding taps of an adjustable transformer. The on-load tap changer includes: at least one selector unit for power-free pre-selection to a selected winding tap; at least one gear transmission mechanism having a first gear and a second gear, the first gear being disposed to the selector unit and the second gear to the load changer unit; and a drive shaft operated by a motor drive. Here, the first gear and the second gear are directly mechanically connected to each other such that the gears can be operated simultaneously. The drive shaft can drive either the first gear or the second gear. Thus, the first gear is the driving gear and the second gear is the driven gear, or vice versa. By directly mechanically coupling the gears, the selector unit and the load changer unit are similarly and centrally operated via the drive shaft. Specifically, this means there is no intermediate link between the gears.

[0008] The preferred transmission ratio of the gear transmission mechanism is i=1. All types of motors can be envisioned as motor drive devices, such as motors operating with direct current, motors operating with alternating current, and regulated and unregulated motor systems.

[0009] The improved design offers the advantage that, through the structural design of the on-load tap changer and, in particular, the transmission mechanism, the drive shaft and motor drive can be variably configured, with the transmission mechanism transmitting the drive motion of the drive shaft to the operating devices of the selector and load transfer switch in the same way. This allows for flexibility in response to limited space availability when transporting the transformer to the point of use, or to given conditions of space at the point of use, such as a substation or gas-insulated switchgear.

[0010] In one possible implementation, the at least one selector unit, the at least one load transfer switch unit, the at least one gear transmission mechanism, and the drive shaft are disposed within the housing of the on-load tap changer. The housing is preferably sealed externally.

[0011] In one possible implementation, the first gear is supported on the first gear shaft without relative rotation, and the second gear is supported on the second gear shaft without relative rotation.

[0012] In one possible implementation, the first gear and the first gear shaft are constructed as a single piece, and the second gear and the second gear shaft are constructed as a single piece.

[0013] In one possible implementation, the first gear shaft is rotatable about a first gear axis and the second gear shaft is rotatable about a second gear axis, and the first gear axis and the second gear axis intersect at a defined angle. Preferably, the first gear axis and the second gear axis intersect at a 90-degree angle.

[0014] In one possible implementation, the first gear and the second gear are each constructed as bevel gears.

[0015] In one possible implementation, the basic shape of the bevel gear is a truncated cone with meshing circumferential surfaces. The teeth can be configured as straight teeth and / or helical teeth. In one possible implementation, the first bevel gear and the second bevel gear overlap at the tips of their teeth.

[0016] In one possible implementation, the first gear and the second gear are constructed identically.

[0017] In one possible implementation, the drive shaft can be connected to the first gear shaft or the second gear shaft via a clutch without relative rotation. Preferably, the clutch is configured as a clutch having multiple clutch housings.

[0018] In one possible implementation, the drive shaft is disposed on the axis of the first gear and / or in an extension of the first gear shaft when driving the first gear, and is disposed on the axis of the second gear and / or in an extension of the second gear shaft when driving the second gear.

[0019] In one possible implementation, the motor drive is fixed to the on-load tap changer by means of a transmission mechanism module. It may be specified that the transmission mechanism module is also configured as a sealed module and externally seals the internal space of the on-load tap changer housing.

[0020] In one possible implementation, the on-load tap changer further includes a switch cabinet, in which at least a control device for the motor drive is provided, and the switch cabinet is constructed separately from the motor drive, i.e., spatially separated. Preferably, the switch cabinet is connected to the motor drive via a cable.

[0021] In one possible implementation, the switchgear is fixed to the housing of the adjustable transformer and / or the housing of the on-load tap changer and / or to suitable mounting hardware. Suitable mounting hardware may be, for example, a wall at the location where the adjustable transformer is used.

[0022] According to one possible implementation, the on-load tap changer is configured as a three-phase on-load tap changer, with each phase having a selector unit, a load transfer switch unit, a drive shaft, and a gear transmission mechanism, that is, a total of three selector units, three load transfer switch units, three drive shafts, and three gear transmission mechanisms.

[0023] In one possible implementation, the on-load tap changer therefore includes a first selector unit, a second selector unit, and a third selector unit; a first load transfer switch unit, a second load transfer switch unit, and a third load transfer switch unit; a first drive shaft, a second drive shaft, and a third drive shaft; and a first gear transmission mechanism, a second gear transmission mechanism, and a third gear transmission mechanism. The first drive shaft operates the first selector unit and the first load transfer switch unit via the first gear transmission mechanism. The second drive shaft operates the second selector unit and the second load transfer switch unit via the second gear transmission mechanism. The third drive shaft operates the third selector unit and the third load transfer switch unit via the third gear transmission mechanism.

[0024] In one possible implementation, the drive shafts are mechanically coupled to each other such that the first drive shaft drives the second drive shaft via a first gear transmission mechanism and the second drive shaft drives the third drive shaft via a second gear transmission mechanism.

[0025] According to a preferred embodiment, the gear transmission mechanism is configured as a bevel gear transmission mechanism.

[0026] In one possible implementation, the second drive shaft and the third drive shaft are on a common axis.

[0027] In one possible implementation, the first drive shaft, the second drive shaft, and the third drive shaft are located on a common axis.

[0028] In one possible implementation, each phase of the on-load tap changer has a first gear and a second gear, and each has a first gear shaft and a second gear shaft.

[0029] In one possible implementation, at least one second gear shaft is provided between the two drive shafts.

[0030] In one possible implementation, the drive shaft and the second gear shaft are connected to each other without relative rotation via at least one clutch. Attached Figure Description

[0031] The invention will now be explained in detail with reference to the accompanying drawings and exemplary embodiments. Identical, functionally identical, or effect-equivalent components may be provided with the same reference numerals. Identical components or components with the same function may be explained only with respect to the first drawing in which they appear. Such explanations are not necessarily repeated in subsequent drawings.

[0032] In the attached image:

[0033] Figure 1 A schematic construction of an adjustable transformer with an exemplary embodiment of an on-load tap changer according to the prior art is shown.

[0034] Figure 2 shows a schematic diagram of the winding taps of an adjustable transformer;

[0035] Figure 3A A top view showing an exemplary embodiment of an on-load tap changer according to an improved design;

[0036] Figure 3B A top view showing another exemplary embodiment of an on-load tap changer according to an improved design;

[0037] Figure 4A A top view showing another exemplary embodiment of an on-load tap changer according to an improved design;

[0038] Figure 4B A top view showing another exemplary embodiment of an on-load tap changer according to an improved design;

[0039] Figure 5A Show Figure 3A and Figure 4A Detailed view of the on-load tap changer;

[0040] Figure 5B Show Figure 3B and Figure 4B Detailed view of the on-load tap changer;

[0041] Figure 6A A schematic diagram of an adjustable transformer with an on-load tap changer of an improved design is shown.

[0042] Figure 6B Another schematic diagram shows an adjustable transformer with an exemplary embodiment of an on-load tap changer according to an improved design. Detailed Implementation

[0043] Figure 1A schematic diagram of an adjustable transformer 1 with an exemplary embodiment of a known on-load tap changer 10 is shown, the on-load tap changer being configured as a mounting switch. The on-load tap changer 10 has a selector 30 and a load transfer switch 40 and is driven by a motor drive 70, the control unit of which is spatially housed in a switch cabinet 72. The on-load tap changer 10, the motor drive 70, and the switch cabinet 72 are disposed within a housing 11.

[0044] Figure 2 schematically illustrates different winding taps N1, ..., N J ..., N N The regulating winding 2 of the adjustable transformer 1 (see Figure 1 Winding taps N1, ..., N J ..., N N The on-load tap changer 10 is used to connect or disconnect the circuit. Connecting or disconnecting can be achieved using any device such as a selector 30, a load transfer switch 40, etc. The on-load tap changer 10 is operated via a motor drive 70.

[0045] Figure 3A The diagram shows a top view of an exemplary embodiment of an on-load tap changer 10 according to an improved design. The on-load tap changer 10 includes a housing 11, selected winding taps N1, ..., N2 for reactively pre-selecting the regulating winding 2 of an adjustable transformer 1. J ..., N N The selector unit 30 (see Figure 2), the load transfer switch unit 40, and the gear transmission mechanism 50 utilize the load transfer switch unit to transfer power from the previous winding tap N of the adjusting winding. J The actual load is transferred to the pre-selected winding tap N. J+1(Not shown) The gear transmission mechanism is constructed as a bevel gear transmission mechanism and has a first bevel gear 31 and a second bevel gear 41. The bevel gears 31 and 41 are constructed as frustocones with meshing circumferential surfaces and are made of a metallic material, preferably steel. The teeth mesh with each other on the meshing circumferential surfaces, so that the bevel gears 31 and 41 are directly, i.e., mechanically connected to each other without any intermediate links. The first bevel gear 31 is assigned to and operates the selector unit 30, and the second bevel gear 41 is assigned to and operates the load changeover switch unit 40. Furthermore, the on-load tap changer 10 has a drive shaft 60, which is connected to the bevel gear transmission mechanism 50 at a first end 61 and to the motor drive unit 70 at a second end 62. The drive shaft 60 is preferably made of an insulating material. The motor drive unit 70 is laterally fixed to the housing 11 in the extension of the drive shaft 60 by means of a transmission mechanism module 71, particularly a sealing module that seals the internal space of the housing 11 outwards. In this embodiment, the drive shaft 60 directly drives the bevel gear 41, i.e., the load transfer switch unit 40. Due to the mechanical connection between the bevel gear 31 and the bevel gear 41, the rotational motion of the bevel gear 41 is directly transmitted to the bevel gear 31, so that the selector unit 30 and the load transfer switch unit 40 are operated in the same way.

[0046] Figure 3B A top view is shown of another exemplary embodiment of the on-load tap changer 10 according to an improved design. In this embodiment, the drive shaft 60 directly drives the bevel gear 31, i.e., the selector unit 30. Due to the mechanical connection between the bevel gears 41 and 31, the load transfer switch unit 40 is operated in the same manner as the selector unit 30. The motor drive unit 70 is fixed to the housing 11 at the end side in the extension of the drive shaft 60 by means of a transmission mechanism module 71.

[0047] Figure 4AA top view is shown of another exemplary embodiment of an on-load tap changer 10 according to an improved design. The on-load tap changer 10 is exemplarily constructed here as a three-phase on-load tap changer and thus includes a total of three selector units 30, 81, and 91, three load transfer switch units 40, 82, and 92, three drive shafts 60, 80, and 90, and three gear transmission mechanisms 50, 83, and 93. Drive shaft 60 operates selector unit 30 and load transfer switch unit 40 via gear transmission mechanism 50, drive shaft 80 operates selector unit 81 and load transfer switch unit 82 via gear transmission mechanism 83, and drive shaft 90 operates selector unit 91 and load transfer switch unit 92 via gear transmission mechanism 93. The three phases, which can be respectively divided into one selector unit 30, 81, and 91, one load transfer switch unit 40, 82, and 92, and one drive shaft 60, 80, and one gear transmission mechanism 50, 83, and 93, are all disposed within a housing 11. Drive shafts 60, 80, and 90 are arranged on a common axis A and mechanically coupled to each other such that the first drive shaft 60 drives the second drive shaft 80 via a gear transmission mechanism 50, and the second drive shaft 80 drives the third drive shaft 90 via a second gear transmission mechanism 83. The first drive shaft 60 is driven by a motor drive unit 70, which is laterally mounted on the housing 11 in an extension of the drive shaft 60. The drive shaft transmits the driving motion to the gear transmission mechanism 50. Therefore, all three phases, with corresponding selector units 30, 81, and 91 and corresponding load changeover switch units 40, 82, and 92, are centrally driven via drive shaft 60.

[0048] exist Figure 5A The middle shows Figure 3A and Figure 4A A detailed view of the on-load tap changer 10, showing the mechanical coupling between the first drive shaft 60 and the second drive shaft 80 via a bevel gear transmission mechanism 50. (In accordance with...) Figure 4A In this embodiment, the coupling between the second drive shaft 80 and the third drive shaft 90 is constructed similarly. A first bevel gear 31 is mounted on the first gear shaft 32 without relative rotation, and a second bevel gear 41 is mounted on the second gear shaft 42 without relative rotation. Gear shafts 32 and 42 are preferably made of a metallic material, such as steel. The first gear shaft 32 is rotatably supported about a gear axis 33, and the second gear shaft 42 is rotatably supported about a gear axis 43. The first gear axis 33 and the second gear axis 43 intersect in a plane at a defined angle α, which is preferably constructed as a right angle. The selector unit 30 includes a driver 34 that is connected to the first gear shaft 32 without relative rotation and operates movable selector contacts (not shown) that correspond to the winding taps N1, ..., N of the adjusting winding 2 of the adjustable transformer 1 (see FIG. 2). J..., N N (Not shown) The contacts are closed. The load transfer switching unit 40 includes an actuating device 44 for a switching element (not shown), which is used to implement the switching from the winding tap N of the regulating winding 2 (see FIG. 2). J The actual load is transferred to the pre-selected winding tap N. J+1 (Not shown). The operating device 44 is configured as a cam disk 44, which is connected to the gear shaft 42 without relative rotation, and the switching element (not shown) is opened and closed, for example, via a lever mechanism, when the cam disk rotates. The switching element (not shown) may preferably be configured as a vacuum switch tube. For example, one cam disk 44 is provided for each vacuum switch tube. The drive shaft 60 is disposed in the extension of the second gear shaft 42 on the second gear axis 43 and is connected to the second gear shaft 42 without relative rotation at the first end 61 via a clutch 63. The motor drive device 70 is disposed on the second end 62 of the drive shaft 60 and drives the drive shaft 60 via a clutch 64. The operation of the load transfer switch unit 40 is performed within a 360-degree rotation of the drive shaft 60 and the gear shaft 42, and the operation of the selector unit 30 is performed due to the coupling of the bevel gears 41 and 31. The motion transmission between the drive shafts 60 and 80 is performed via the clutch 63, the second gear shaft 42, and another clutch 84 that connects the drive shaft 80 to the second gear shaft 42 without relative rotation. Preferably, clutches 62, 64, and 84 each have two clutch housings. However, in principle, each type of coupling can be used.

[0049] Figure 4B A top view is shown of another exemplary embodiment of an on-load tap changer 10 according to an improved design. The on-load tap changer 10 is also exemplaryly constructed as a three-phase switch. According to this embodiment, the motor drive 70 is similar to... Figure 3B The embodiment shown has the drive shaft 60 extended and mounted on the housing 11 at one end, meaning the drive shaft 60 directly drives the first gear 31, as described below by means of... Figure 5B The description is as accurate as it is explained. The coupling between the second drive shaft 80 and the third drive shaft 90 is similar to that in... Figure 5A The arrangement structure shown is constructed.

[0050] Figure 5B Show Figure 3B and Figure 4BA detailed view of the on-load tap changer 10 is shown. Here, the drive shaft 60 is disposed on the first gear axis 33 in the extension of the first gear shaft 32 and is connected to the first gear shaft 32 without relative rotation at its first end 61 via a clutch 63. Therefore, the drive shaft 60 directly drives the first gear 31, which transmits motion to the second gear 41, which is disposed on the second gear shaft 42 without relative rotation. Rotational motion is transmitted from the second gear shaft 42 to the second drive shaft 80 via a clutch 84.

[0051] Figure 6A A schematic diagram of an adjustable transformer 1 with an exemplary embodiment of an on-load tap changer 10 according to an improved design is shown. In this embodiment, the on-load tap changer 10 is implemented as a mounting switch, which is housed in a housing 11 and disposed on the outside of a transformer housing 3. A motor drive 70 is laterally mounted on the housing 11 of the on-load tap changer 10. A corresponding switch cabinet 72 is mounted on the transformer housing 3 and connected to the motor drive 70 via a cable 73.

[0052] Figure 6B Another schematic diagram shows an adjustable transformer 1 having an exemplary embodiment of an on-load tap changer 10 according to an improved design. In this embodiment, a motor drive 70 is mounted on the housing 11 of the on-load tap changer 10 at one end. A corresponding switch cabinet 72 is also mounted on the housing 11 of the on-load tap changer 10 at one end and is connected to the motor drive 70 via a cable 73.

[0053] However, the arrangement of the switchgear 72 is not limited to the embodiment shown. The switchgear 72 can be fixed in principle anywhere at the location of the transformer, for example, fixed to a nearby wall, within a defined distance from the on-load tap changer 10, due to flexible cable connections, said distance being related, for example, to cable length and / or drive solution.

[0054] The improved design of the on-load tap changer 10 allows for flexible adaptation to different spatial requirements, whether transported to or directly at the point of use. The motor drive can be variably mounted on the end or side of the on-load tap changer housing. Similarly, the switch cabinet can be variably and separately arranged from the motor drive and the on-load tap changer. This is advantageous, for example, when replacing an old on-load tap changer with a new one, as the space previously occupied by the old on-load tap changer may then be available only for the space designated for mounting the transformer housing. Furthermore, the improved design is advantageous, for example, when transporting a transformer with an on-load tap changer. This is primarily due to the additional space required for the installation of the switch, where the on-load tap changer with its associated motor drive and switch cabinet is located. The improved design allows for the efficient use of available space, for example, in a railcar or truck, and for space-saving transport of the on-load tap changer with the transformer. Furthermore, the switchgear according to the improved design can also be transported separately and then assembled in suitable locations at the point of use (see [reference]). Figure 6A and Figure 6B This allows for flexible responses to different spatial conditions during transport and at the point of use.

[0055] It is assumed that this disclosure and its many accompanying advantages have been understood through the above description. Furthermore, it will be apparent that various changes can be made to the form, construction, and arrangement of the components without departing from the disclosed technical solution or abandoning all substantial advantages. The described embodiments are merely illustrative, and such variations are covered by the appended claims. Moreover, it is self-evident that the invention is defined by the appended claims.

[0056] List of reference numerals

[0057] 1 Adjustable Transformer

[0058] 2. Adjustable winding of an adjustable transformer

[0059] 3 Transformer housing

[0060] 10 On-load tap changers

[0061] 11 Casing

[0062] 30 selector units

[0063] 31 First Gear

[0064] 32 First gear shaft

[0065] 33 First gear axis

[0066] Driver for 34 selector units

[0067] 40 Load Transfer Switch Unit

[0068] 41 Second Gear

[0069] 42 Second gear shaft

[0070] 43 Second gear axis

[0071] 44. Cam disc / operating device of load transfer switch unit

[0072] 50 Gear Transmission Mechanism

[0073] 60 drive shaft

[0074] The first end of the 61 drive shaft

[0075] 62 drive shaft second end

[0076] 63 Clutch on the first end

[0077] 64 Clutch at the second end

[0078] 70 motor drive unit

[0079] 71 Transmission Mechanism Module

[0080] 72 switch cabinet

[0081] 73 cable

[0082] 80 Second Drive Shaft

[0083] 81 Second Selector Unit

[0084] 82 Second Load Transfer Switch Unit

[0085] 83 Second Gear Transmission Mechanism

[0086] 84 Clutch

[0087] 90 Third Drive Shaft

[0088] 91 Third Selector Unit

[0089] 92 Third Load Transfer Switch Unit

[0090] 93 Third Gear Transmission Mechanism

[0091] α angle

[0092] Axis A

[0093] N1、...N J ..., N N The winding taps of an adjustable transformer.

Claims

1. For use in the winding taps (N1, ... N) of an adjustable transformer (1) J ..., N N An on-load tap changer (10) that allows for uninterrupted switching between different on-load taps, the on-load tap changer comprising: At least one selector unit (30) is used for powerless pre-selection to the selected winding tap (N). J )superior; At least one load transfer switching unit (40) is used to switch from the previous winding tap (N) J-1 The actual load is transferred to the pre-selected winding tap (N). J )superior; At least one gear transmission mechanism (50) having a first gear (31) and a second gear (41), the first gear (31) being disposed to the selector unit (30) and the second gear (41) being disposed to the load changeover switch unit (40). A drive shaft (60) is operated by a motor drive device (70); The first gear (31) and the second gear (41) are directly mechanically connected to each other, so that the first gear (31) and the second gear (41) can be operated simultaneously; The first gear (31) is supported on the first gear shaft (32) without relative rotation, and the second gear (41) is supported on the second gear shaft (42) without relative rotation. The first gear shaft (32) is rotatable about the first gear axis (33), and the second gear shaft (42) is rotatable about the second gear axis (43). Its features are, The drive shaft (60) can drive the first gear (31) or the second gear (41). The drive shaft (60) is located on the first gear axis (33) when driving the first gear (31) and on the second gear axis (43) when driving the second gear (41).

2. The on-load tap changer (10) according to claim 1, wherein, The at least one selector unit (30), the at least one load changeover switch unit (40), the at least one gear transmission mechanism (50) and the drive shaft (60) are disposed in the housing (11) of the on-load tap changer (10).

3. The on-load tap changer (10) according to claim 1, wherein, The first gear axis (33) and the second gear axis (43) intersect at a defined angle (α).

4. The on-load tap changer (10) according to any one of claims 1 to 3, wherein, The first gear (31) and the second gear (41) are constructed as bevel gears.

5. The on-load tap changer (10) according to any one of claims 1 to 3, wherein, The drive shaft (60) can be connected to the first gear shaft (32) or the second gear shaft (42) without relative rotation via a clutch (63).

6. The on-load tap changer (10) according to any one of claims 1 to 3, wherein, The motor drive unit (70) can be fixed to the housing (11) of the on-load tap changer (10) by means of the transmission mechanism module (71).

7. The on-load tap changer (10) according to any one of claims 1 to 3, wherein the on-load tap changer further comprises a switch cabinet (72) which is constructed separately from the motor drive device (70).

8. The on-load tap changer (10) according to any one of claims 1 to 3, wherein the on-load tap changer comprises The second selector unit (81) and the third selector unit (91). The second load transfer switch unit (82) and the third load transfer switch unit (92). Second drive shaft (80) and third drive shaft (90). The second gear transmission mechanism (83) and the third gear transmission mechanism (93); among which, The second drive shaft (80) operates the second selector unit (81) and the second load changeover switch unit (82) via the second gear transmission mechanism (83). The third drive shaft (90) operates the third selector unit (91) and the third load changeover switch unit (92) via the third gear transmission mechanism (93).

9. The on-load tap changer (10) according to claim 8, wherein, The drive shaft (60), the second drive shaft (80) and the third drive shaft (90) are mechanically coupled to each other, such that the drive shaft (60) drives the second drive shaft (80) via the gear transmission mechanism (50), and the second drive shaft (80) drives the third drive shaft (90) via the second gear transmission mechanism (83).

10. The on-load tap changer (10) according to claim 8, wherein, The second drive shaft (80) and the third drive shaft (90) are on a common axis (A).

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