TEST SYSTEM

Description

[0001] The invention relates to a system comprising a test vehicle equipped with at least one test device, which is designed to be inserted into the air gap between a rotor and a stator of an electrical machine, in particular a generator, which stator has axially extending laminated core teeth and copper rods arranged between the laminated core teeth and to be moved in a straight line along the laminated core teeth of the stator in order to test the condition of the stator in the region of the inner circumferential surface and / or the condition of the rotor in the region of the outer circumferential surface using the at least one test device.

[0002] The rotor and stator of a generator in a stationary gas turbine plant are subjected to a visual inspection at regular overhaul intervals and, if necessary, when unusual events occur, such as load shedding. The inspection is carried out to identify and locate any thermal discoloration, mechanical changes such as scratches, impacts, displacement of parts, loose parts, foreign objects, etc. To enable visual access, the rotor is usually removed or pulled out of the stator. This is followed by a visual inspection by the inspection personnel. Any findings are documented photographically. The generator can only be reassembled and put into operation once the inspection has been completed and the test results have been evaluated, and any necessary repair work has been carried out. However, removing the rotor is associated with considerable effort and high costs.

[0003] One option for a visual inspection of the assembled stator and rotor is generally the use of a conventional industrial endoscope. However, this does not apply to generators of stationary gas turbine plants with rotor lengths of several meters.

[0004] Furthermore, inspection vehicles equipped with at least one inspection device are known. These vehicles are designed to be inserted into the air gap between a rotor and a stator of an electrical machine, in particular a generator, which stator has axially extending lamination stack teeth and copper rods arranged between the lamination stack teeth. They are then moved in a straight line along the stator's lamination stack teeth in order to inspect the condition of the stator in the region of the inner circumferential surface and / or the condition of the rotor in the region of the outer circumferential surface using the at least one inspection device. Such an inspection vehicle is offered, for example, by ABB under the product name "Air Gas Inspector." A camera system is provided as the inspection device, enabling the visual inspection of the rotor and stator. A significant advantage is that the inspection of the rotor and stator can be largely automated.A disadvantage, however, is that the test vehicle must be manually moved in the circumferential direction after each axial run before the next axial test run can be performed. For many generators, particularly those used in industrial applications, the use of this test device is not possible at all, as the air gap between the rotor and the stator is usually only accessible via a one-sided access at the 12 o'clock position, which makes manual movement of the test vehicle in the circumferential direction impossible.

[0005] US 2019 / 126486 A1 discloses a system comprising a test vehicle equipped with at least one test device, which is designed to be inserted into the air gap between a rotor and a stator of an electrical machine, in particular a generator, having axially extending laminated core teeth and copper rods arranged between the laminated core teeth, and to be moved in a straight line along the laminated core teeth of the stator in order to test the condition of the stator in the region of the inner circumferential surface and / or the condition of the rotor in the region of the outer circumferential surface using the at least one test device.

[0006] Similar information is disclosed in US 2007 / 089544 Al.

[0007] Based on this prior art, it is an object of the present invention to provide a system of the type mentioned at the outset which can be used more flexibly and is easier to handle.

[0008] To achieve this object, the present invention provides a system of the type mentioned at the outset, which is characterized in that the system further comprises a lane change unit which can be inserted into the air gap between the rotor and the stator and can be moved on the stator in the circumferential direction, comprising a parking cassette which is designed to accommodate the test vehicle and into which the test vehicle can drive in and out in the axial direction through a parking cassette opening, at least one drive unit which is preferably pivotably connected to the parking cassette and has at least one motor, which is designed to move the lane change unit in the circumferential direction together with the test vehicle accommodated in the parking cassette, and a controller for controlling at least the lane change unit.With such a system, the test vehicle can be temporarily parked in the parking cassette of the lane-changing unit and, in this parked state, moved circumferentially along the stator together with the lane-changing unit. Accordingly, manual movement of the test vehicle in the circumferential direction after each axial test run is no longer necessary. This saves time. Furthermore, the operating personnel do not have to remain in a very confined space for extended periods. Furthermore, a very high degree of automation is achieved. As a result, the test can be performed quickly, easily, and cost-effectively.

[0009] According to one embodiment of the present invention, the lane-changing unit comprises two drive units positioned on circumferentially opposite sides of the parking cassette and connected to the parking cassette. Accordingly, a symmetrical structure with even weight distribution is achieved, which greatly contributes to the reliable operation of the lane-changing unit.

[0010] Advantageously, each drive unit has at least two driven drive chains. Thanks to such drive chains, which comprise rubber-like material, particularly on the surfaces contacting the stator, unevenness of the stator surface along the movement path of the lane-changing unit can be easily bridged.

[0011] Advantageously, a sensor is provided on the parking cassette that detects the presence of the test vehicle within the parking cassette, particularly in the form of a distance sensor. The control system can thus set the lane change unit in motion as soon as it receives the corresponding signal from the distance sensor, indicating that the test vehicle is properly parked in the parking cassette.

[0012] The lane-changing unit preferably has at least one sensor that detects the spatial position of the lane-changing unit, particularly in the form of a gyroscope sensor. Such a sensor can be used to detect the spatial position of the lane-changing unit and, given the stator structure, the position relative to the stator. Based on the sensor signal, the controller can determine, for example, whether the lane-changing unit has been moved to the desired new position in order to then stop the at least one drive unit.

[0013] Advantageously, the lane-changing unit has at least one camera monitoring the area in front of the parking cassette opening. In particular, two cameras are provided, positioned circumferentially on either side of the parking cassette opening. The at least one camera serves to visually monitor the parking and exiting of the test vehicle.

[0014] Preferably, at least one lighting unit is provided to illuminate the image area of ​​the at least one camera. In particular, two lighting units are provided, for example in the form of LED strips, which are positioned adjacent to the respective camera, in particular on the drive units.

[0015] Advantageously, the lane-changing unit comprises accumulator units, which are preferably positioned on the at least one drive unit. These accumulator units supply the lane-changing unit with energy independently.

[0016] According to one embodiment of the present invention, the overall height of the lane change unit with the test vehicle accommodated in the parking cassette, when the lane change unit is placed on a level surface, is 19 mm or less. With such an overall height, the system can be used with a wide range of generators, thus achieving a high degree of flexibility.

[0017] The lane change unit is preferably radio-controlled.

[0018] The test vehicle is advantageously wired, since ensuring a sufficiently good radio connection in the air gap between the rotor and stator is very complex. Furthermore, in the event of a failure, the test vehicle can be easily pulled out of the air gap via the cable and thus evacuated. The cable is preferably routed through a cable feedthrough opening provided on an axial end wall of the parking cassette, thus achieving a simple design.

[0019] Advantageously, the test vehicle and the lane change unit are provided with a plurality of magnets on their respective undersides, as is already known in particular from test vehicles of the prior art, in order to hold the test vehicle and the lane change unit on the stator, even if they are in an overhead position.

[0020] Furthermore, to achieve the object mentioned at the outset, the invention provides a method for testing an electrical machine having a rotor and a stator having axially extending laminated core teeth and copper bars arranged between the laminated core teeth, using a system according to one of the preceding claims, comprising the steps: a) Inserting the lane change unit with the test vehicle accommodated therein into the air gap between the rotor and the stator and placing the assembly onto the stator; b) Moving the test vehicle in a straight line in the axial direction along the stator's laminated core teeth, wherein the test vehicle, using the at least one testing device, checks the condition of the stator in the region of the inner circumferential surface and / or the condition of the rotor in the region of the outer circumferential surface along the axial travel path; c) Parking the test vehicle in the parking cassette of the lane change unit; d) Moving the lane change unit together with the test vehicle accommodated therein in the circumferential direction along the stator; Repeat steps b) to d), in particular until the lane change unit has been moved 360° in the circumferential direction.

[0021] Further advantages and features of the invention will become apparent from the following description with reference to the accompanying drawings. Figure 1 is a schematic perspective partial view of a stator of an electrical machine, onto which a test vehicle and a lane change unit of a system according to an embodiment of the present invention are mounted; Figure 2 is a plan view of the Figure 1 illustrated arrangement; Figure 3 is an enlarged plan view of the lane change unit, wherein the upper housing walls of drive units of the lane change unit are shown transparent for illustration purposes; Figure 4 is a perspective partial plan view of the lane change unit, in which the top of the housing of a parking cassette of the lane change unit, in which the test vehicle is accommodated, is also shown transparent and partially open; and Figure 5 is a schematic side view of the machine to be tested.

[0022] The Figures 1 to 4 show a system 1 according to an embodiment of the present invention and components thereof. The system 1 serves to check the condition of a stator 4, comprising laminated core teeth 2 and copper rods 3 arranged between the laminated core teeth 2, and / or a rotor 5 of an electrical machine 6 in order to detect damage so that it can be subsequently repaired. The electrical machine 6 in this case is a generator of a stationary gas turbine plant. The main components of the system 1 are a test vehicle 7, a lane-changing unit 8, and a controller 9.

[0023] The test vehicle 7 is designed to be inserted into the air gap 10 between the rotor 5 and the stator 4 and to be moved in a straight line in the axial direction A along the laminated core teeth 2 of the stator 4 in order to test the condition of the stator 4 in the region of the inner circumferential surface and / or the condition of the rotor 5 in the region of the outer circumferential surface. In the illustrated embodiment, the test vehicle 7 comprises a frame 11 on which two electric motors 12 are mounted, each driving a drive chain 13. The drive chains 13 extend parallel to one another and, in this case, have rubber-like material on the surfaces contacting the stator 4 or are made of such a material.The distance between the drive chains 13 can be varied in the direction of the double arrow 14, so that the test vehicle 7 can be placed on laminated core teeth 2 of the stator 4 of the electrical machine 6 to be tested, which are spaced apart at different distances from one another, as shown in . Figure 1is shown. Magnets (not shown in detail) are preferably positioned on the underside of the frame 11, the number, positions and strength of the magnets being selected such that the test vehicle 7 is held securely on the stator 4 even in an overhead position. A testing device 15 is positioned in the front area of ​​the frame 11, which in this case comprises a camera 16 and an ultrasonic sensor 17. A cable 18 extends from the rear area of ​​the test vehicle 7, via which cable the test vehicle 7 is connected to the controller 9 for power and data. In principle, the structure of the test vehicle 7 can be designed as desired to fulfill the purpose mentioned above. The testing device 15 of the test vehicle 7 can also have any sensors that enable appropriate diagnosis of the stator 4 and / or rotor 5.

[0024] The lane-changing unit 8 is designed such that it can also be inserted into the air gap 10 between the rotor 5 and the stator. It serves to transport the test vehicle 7, which is primarily movable in a straight line, in the circumferential direction U of the stator 4. In the embodiment shown, the lane-changing unit 8 comprises a parking cassette 19, which is designed to accommodate the test vehicle 7 and into which the test vehicle 7 can drive in and out in the axial direction A through a parking cassette opening 20, as well as two drive units 21 pivotally connected to the parking cassette 19 on opposite sides, which drive units 21 are designed to move the lane-changing unit 8 together with the test vehicle 7 accommodated in the parking cassette 19 in the circumferential direction U.The dimensions of the parking cassette 19 are adapted to the dimensions of the test vehicle 7 such that the test vehicle 7 can drive into the parking cassette 19 through the parking cassette opening 20 and be accommodated therein. A cable feedthrough opening 22 is provided in the rear area of ​​the parking cassette 19, through which the cable 18 of the test vehicle 7 is routed. Furthermore, a sensor 23 is provided inside the rear area of ​​the parking cassette 19. This sensor detects the presence of the test vehicle 7 within the parking cassette 19 and is designed as a distance sensor in this case. Accordingly, the sensor 23 can detect whether the test vehicle 7 is properly parked in the parking cassette 19 or not. In the front area of ​​the parking cassette 19, adjacent to the parking cassette opening 20, two cameras 24 are positioned to monitor the area in front of the parking cassette opening 20.The drive units 21 each comprise two motors 25 in the form of electric motors, which drive associated drive chains 26 extending parallel to one another in the circumferential direction U of the stator 4 and which can also be made of a rubber-like material. For energy supply, each drive unit 21 is provided in this case with an accumulator unit 27. Furthermore, the drive units 27 are equipped with circuit boards 28 on which voltage regulators 29, motor drivers 30, a microcontroller 31, and the like are positioned. One of the circuit boards 28 is further provided with a sensor 32, which detects the position of the lane-changing unit 8 in space, in this case in the form of a gyroscope sensor. Furthermore, a radio unit 34, provided with an antenna 33, is positioned on one of the circuit boards 28 and provides the data connection to the controller 9.To illuminate the image area of ​​the two cameras 24 positioned on the parking cassette 19, lighting units 35, in this case in the form of LED light strips, are provided on the respective drive units 21. The total height of the lane change unit 8 with the test vehicle 7 accommodated in the parking cassette 19 is advantageously 19 mm or less when the lane change unit 8 is placed on a level surface.

[0025] The controller 9 communicates via cable with the test vehicle 7 and wirelessly with the lane change unit 8, for which purpose the controller 9 is provided with an antenna 36. The cable-based communication with the test vehicle 7 ensures a functional data connection in the radio-technically problematic environment within the air gap 10. Furthermore, the test vehicle 7 can be easily retrieved from the air gap 10 by pulling on the cable 18 in the event of a malfunction of the test vehicle 7.

[0026] To test the electrical machine 6 using the system 1 described above, with reference to Figure 5The following steps are carried out. In a first step, the lane change unit 8 with the test vehicle 7 accommodated in the parking cassette 19 is inserted into the air gap 10 between the rotor 5 and the stator 4 and placed on the stator 4 in such a way that the drive chains 13 of the test vehicle 7 are aligned with two adjacent laminated core teeth 2 of the stator 4 and thus point in the axial direction A. The drive chains 26 of the drive units 21 of the lane change unit 8, on the other hand, point in the circumferential direction U of the stator 4. In a further step, the test vehicle 7 is moved out of the parking cassette 19 in the axial direction A along the laminated core teeth 2 of the stator 4, wherein the test vehicle 7, using the testing device 15, checks the condition of the stator 4 in the area of ​​the inner circumferential surface and / or the condition of the rotor 5 in the area of ​​the outer circumferential surface along the axial travel path.The sensor data from the sensors of the test device 15 is transmitted to the controller 9 via the cable 18. The test vehicle 7 is then moved back axially and parked again in the parking cassette 19 of the lane-changing unit 8. Proper reaching of the parking position is detected by the sensor 23 and transmitted to the controller 9 via the radio unit 34. The lane-changing unit 8, together with the test vehicle 7 accommodated therein, is now moved in the circumferential direction U along the stator 4 by actuating the drive units 21 until the drive chains 13 of the test vehicle 7 are axially aligned with the two adjacent laminated core teeth 2, which is detected by the cameras 24 and transmitted to the controller 9 via the radio unit 34. The test vehicle 7 then performs another test run in the axial direction A.The movement of the lane change unit 8 and the test runs 7 of the test vehicle are repeated until the lane change unit 8 has moved 360° in the circumferential direction U and a complete test has been carried out accordingly.

[0027] The system 1 described above is particularly characterized by the fact that manual movement of the test vehicle 7 in the circumferential direction U of the stator 4 is eliminated after each axial test run of the test vehicle 7. This saves personnel costs and time, and increases the degree of automation of the test, resulting in a significant cost reduction.

[0028] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited to the disclosed examples and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims

1. System (1) comprising a test vehicle (7) which is equipped with at least one test device (15) and is conceived to be inserted into the air gap (10) between a rotor (5) and a stator (4) of an electric machine (6), in particular of a generator, which stator (4) has axially extending laminated core teeth (2) and copper rods (3) disposed between the laminated core teeth (2), and to be rectilinearly displaced along the laminated core teeth (2) of the stator (4) so as to test the state of the stator (4) in the region of the internal circumferential face and / or the state of the rotor (5) in the region of the external circumferential face while using the at least one test device (15), characterized in that the system (1) furthermore has a track changeover unit (8) which is insertable into the air gap (10) between the rotor (5) and the stator (4) and is displaceable in the circumferential direction (U) on the stator (4), comprising a parking cassette (19) which is conceived for receiving the test vehicle (7) and which the test vehicle (7) can move into and out of in the axial direction (A) through a parking cassette opening (20), at least one drive unit (21) which is preferably pivotably connected to the parking cassette (19) and has at least one motor (25) and is conceived to move the track changeover unit (8), conjointly with the test vehicle (7) received in the parking cassette (19), in the circumferential direction (U), and a controller (9) for controlling at least the track changeover unit (8).

2. System (1) according to Claim 1, characterized in that the track changeover unit (8) has two drive units (21) which are positioned on sides of the parking cassette (19) which are mutually opposite in the circumferential direction (U), and are connected to the parking cassette (19).

3. System (1) according to one of the preceding claims, characterized in that each drive unit (21) has at least two driven drive chains (26).

4. System (1) according to one of the preceding claims, characterized in that a sensor (23), in particular in the form of a distance sensor, which detects the presence of the test vehicle (7) within the parking cassette (19) is provided on the parking cassette (19).

5. System (1) according to one of the preceding claims, characterized in that the track changeover unit (8) has at least one sensor (32), in particular in the form of a gyroscopic sensor, which detects the spatial position of the track changeover unit (8).

6. System (1) according to one of the preceding claims, characterized in that the track changeover unit (8) has at least one camera (24) monitoring the region in front of the parking cassette opening (20).

7. System (1) according to Claim 6, characterized in that at least one illumination unit (35) illuminating the imaging region of the at least one camera (24) is provided.

8. System (1) according to one of the preceding claims, characterized in that the track changeover unit (8) has accumulator units (27) which are preferably positioned on the at least one drive unit (21).

9. System (1) according to one of the preceding claims, characterized in that, when the track changeover unit is placed on a flat surface, the overall height of the track changeover unit (8) including the test vehicle (7) received in the parking cassette (19) is 19 mm or less.

10. System (1) according to one of the preceding claims, characterized in that the track changeover unit (8) is radio controlled.

11. System (1) according to one of the preceding claims, characterized in that the test vehicle (7) is tethered, wherein the cable (18) is preferably routed through a cable feedthrough opening (22) provided on an axial end wall of the parking cassette (19).

12. System (1) according to one of the preceding claims, characterized in that the test vehicle (7) and the track changeover unit (8) on their respective lower side are provided with a plurality of magnets.

13. Method for testing an electric machine (6) having a rotor (5) and a stator (4) which has axially extending laminated core teeth (2) and copper rods (3) disposed between the laminated core teeth (2), while using a system (1) according to one of the preceding claims, said method comprising the following steps: a) inserting the track changeover unit (8) including the test vehicle (7) received therein into the air gap (10) between the rotor (5) and the stator (4), and placing the assembly onto the stator (4); b) rectilinearly displacing the test vehicle (7) in the axial direction (A) along the laminated core teeth (2) of the stator (4), wherein the test vehicle (7), while using the at least one test device (15), tests the state of the stator (4) in the region of the internal circumferential face and / or the state of the rotor (5) in the region of the external circumferential face along the axial displacement path; c) parking the test vehicle (7) in the parking cassette (19) of the track changeover unit (8); d) displacing the track changeover unit (8), conjointly with the test vehicle (7) received therein, in the circumferential direction (U) along the stator (4); e) repeating steps b) to d), in particular until the track changeover unit (8) has been displaced by 360° in the circumferential direction (U).