Methods for impregnating and impregnating device

Abstract

The invention relates to methods for impregnating a body (4) supporting at least one winding (41), in particular for an electric machine (1), for example for a rotor (3) or stator (2), wherein the body (4) is sprinkled with an impregnating material (6) which preferably comprises resin, wherein a voltage pulse is applied to the winding, in particular during and / or after the impregnation, and wherein a partial discharge that occurs is detected by means of a microphone.

Description

[0001] Description

[0002] Impregnation process and an impregnation device

[0003] The invention relates to a method for impregnation and an impregnation device.

[0004] The impregnation of electric motors, in particular the immersion, dripping or coating of the rotors and / or stators with, preferably liquid, impregnating resin and the usually subsequent, in particular thermal, curing, is often designed in a similar way in the motor manufacturing process. There is usually a predefined, calibrated process (e.g. in the case of an immersion process: preheating, immersion in liquid resin and curing or in the case of a trickling process: preheating, trickling of the liquid resin and curing), which is usually not adapted to a specific component, but represents a technical and economic optimum for the available sizes, particularly with regard to times, speeds and temperatures of the ovens for thermal curing. The quality of the process can only be determined retrospectively.

[0005] DE 10 2021 124 670 B3 relates to a test device for locating a partial discharge in or on an electrical component. The test device has one or more antennas for detecting an electromagnetic wave caused by a partial discharge in the electrical component. The test device includes a plurality of microphones which are arranged in the predetermined environment around the electrical component, wherein the microphones are designed to detect acoustic sound waves caused by the partial discharge. It is checked whether the intensity of the electromagnetic wave detected by one of the plurality of antennas exceeds a first limit value and / or the intensity of the sound wave detected by one of the plurality of microphones exceeds a second limit value.Depending on the detected sound wave and / or electromagnetic wave and the verification of the first and / or second limit value, a location of the partial discharge can be determined.

[0006] DE 10 2011 052 141 A1 relates to a method for impregnating electrical components with a wound body with an impregnating resin. Reliable quality monitoring is achieved by monitoring or testing the impregnation quality during the impregnation process, with the impregnating resin heated, at least temporarily performing a capacitance measurement on the component in the region of the wound body coated with impregnating resin, and by generating display information and / or providing output data for a process control system based on the capacitance measurement.

[0007] DE 20 2019 001 441 Ul discloses an impregnation device for the trickle impregnation of a stator of an electric machine with a synthetic resin that hardens under temperature increase, wherein the stator has a hollow cylindrical stator core and at least one winding, wherein a drive shaft is arranged coaxially within the stator, which drive shaft can be driven by a drive motor, wherein at least one holding device is arranged on the drive shaft, by means of which the stator can be detachably connected to the drive shaft, wherein a trickle device is provided, by means of which the synthetic resin can be conducted to at least one axial end of the winding of the stator, wherein a heating device is provided, by means of which the winding and the stator core can be heated to a predetermined trickle temperature, and wherein the heating device has at least one electromagnetic inductor, which is arranged so as to be movable coaxially or axially parallel to the stator,characterized in that at least one temperature sensor is arranged radially inside the stator core, by means of which the temperature on the radial inside of the stator core and / or the winding can be measured. The invention is based on the object of improving the impregnation of electric motors in this regard.

[0008] The object is achieved by a method according to claim 1, i.e. a method for impregnating a body carrying at least one winding, in particular for an electrical machine, for example for a rotor or stator, wherein the body is sprinkled with an impregnating material, preferably containing resin, wherein the winding, in particular during and / or after the impregnation, is subjected to a voltage pulse, wherein any partial discharge which occurs is detected by a microphone.

[0009] An advantageous design is one in which the occurring partial discharge is detected acoustically by an ultrasonic directional microphone.

[0010] An advantageous design is one in which the ultrasonic directional microphone is moved axially over the body.

[0011] An advantageous embodiment is one in which a spot on the body at which a partial discharge (abbreviated to TE) was detected is sprinkled again.

[0012] Particularly with regard to later loading of the body, in particular the stator or rotor of an electrical machine, due to, for example, pulses with steep edges and overvoltages in converter operation, it is advantageous to detect weak points in the system during impregnation in order to directly and specifically increase a PD inception voltage and thus the quality of the entire system by subsequently dosing, for example, liquid impregnation resin in the critical area.

[0013] Field failures of electrical machines, especially the windings of these machines, are often caused by a weak point in the insulation system, which is why the probability of failure and thus the statistical service life of the machine can be increased by targeted optimization of these areas.

[0014] The invention offers the advantage that a PD measurement can be carried out via connecting cables during the trickle-down process. Using suitable sensors, such as the aforementioned ultrasonic directional microphones, areas in the winding heads and in the slots can be detected which still represent a weak point in the insulation system at the time of the measurement. A spatially resolved measurement can therefore be carried out in situ, which reveals resin deficiencies or wire crossings. The impregnating resin, which is still liquid at this time, is also advantageous due to its significantly higher dielectric constant (10-15 instead of 3-5) compared to the cured molding material, as the electric field strength is displaced more strongly into defects (dielectric constant of air = 1), whereby partial discharges can occur and be detected in the aforementioned areas even at lower applied test voltages.Since this spatially resolved measurement can be carried out during the impregnation process, liquid impregnation resin can now be added in a targeted manner via the resin dosing device in order to mitigate the identified weak points.

[0015] This allows stators, rotors, or other bodies carrying a winding to be manufactured with minimal effort, at least essentially free of weak points within the required quality range, and even higher individual requirement classes can be achieved without significantly increasing economic costs. Because complete double impregnation is not necessary, material and production time can be saved. The probability of motor failure in the field is significantly reduced, since failure mechanisms at weak points in the insulation system can be detected and remedied during production.

[0016] A dosing location could be, for example, a winding head (inside and / or outside, slot exit, various phases). The process is particularly well-suited for rotors and / or stators of dynamoelectric rotary machines. Furthermore, the process is also suitable for impregnating electrical machines in general, e.g., transformers.

[0017] In the context of the present invention, impregnation advantageously means impregnation, solidification or electrical insulation.

[0018] The impregnation material preferably contains resin.

[0019] The resin is preferably such that it hardens when the temperature increases.

[0020] The impregnating material may comprise exclusively resin. The impregnating material may also be a resin-hardener mixture, particularly in the form of a multi-component resin system comprising at least two components, a first component being a resin and a second component being a hardener.

[0021] The resin is preferably an epoxy resin.

[0022] The hardener is advantageously amine-based.

[0023] The body is moved around a rotation axis before and / or during and / or after sprinkling.

[0024] The body advantageously does not undergo continuous rotation, but rather oscillates advantageously between two positions.

[0025] An advantageous design is one in which the capacity is determined cyclically.

[0026] Particularly advantageously, a cycle lasts at least two seconds and at most 20 seconds, preferably at least five and at most ten seconds. This offers the advantage that, if measurements are taken every five to ten seconds, e.g., between heating phases, a fill level distribution over time can be determined.

[0027] An embodiment is advantageous according to which the body is rotated by a first angle in a first direction of rotation, preferably in a positive direction of rotation, wherein the body is rotated by the negative first angle or a second angle in a second direction of rotation, preferably in a negative direction of rotation.

[0028] In other words, this means that the body is rotated by a first angle in the forward direction, whereby the body is rotated by the first angle or a second angle in the backward direction.

[0029] The body rotates in a pendulum motion. The body does not exhibit continuous motion with a specific angular velocity.

[0030] Advantageously, the body is moved in the first direction of rotation, stopped (i.e. speed = 0) and then moved in the second direction of rotation.

[0031] An embodiment is advantageous according to which the body is moved in the first direction of rotation at a first rotational speed, wherein the body is moved in the second direction of rotation at a second rotational speed, wherein the first rotational speed is greater than the second rotational speed.

[0032] In this way, a particularly homogeneous distribution of the impregnation material can be achieved.

[0033] A design that adjusts the rotation speed depending on the determined capacity is advantageous. This offers the advantage of achieving good resin distribution.

[0034] An advantageous embodiment is one in which the impregnation material is directed onto the body or in the direction of the body by means of a dosing nozzle.

[0035] In this way, the drizzling is particularly good and even.

[0036] Two or more dosing nozzles can also be formed.

[0037] An embodiment is advantageous according to which a dosage amount applied to the body when it is moved in the first direction of rotation is greater than a dosage amount applied to the body when it is moved in the second direction of rotation.

[0038] In other words, this means that the dosing quantity can, for example, reach a maximum during a full rotation of 360° in the forward direction and then reach a minimum in the reverse direction.

[0039] A transition from maximum to minimum can be abrupt.

[0040] A transition from maximum to minimum can also be smooth.

[0041] This can prevent dripping.

[0042] An advantageous embodiment is one in which the impregnating material is directed to an axial end of the body.

[0043] This is particularly advantageous when the body is tilted relative to the horizontal. The impregnating material, e.g., resin, is preferably applied to the axial end of the body that is higher relative to the earth's surface than the other axial end. The impregnating material can advantageously flow due to the tilted position toward the other axial end or toward a point where the impregnation is to end. The body can be fully or partially impregnated.

[0044] It is particularly advantageous if the body rotates when the impregnating material is applied. This allows for a particularly homogeneous distribution of the impregnating material.

[0045] Alternatively or additionally, the nozzle can be moved.

[0046] An advantageous embodiment is one in which the dosing nozzle is moved, preferably parallel to the body.

[0047] This has the advantage that every part of the body can be easily sprayed.

[0048] The nozzle can be moved while the body is rotated.

[0049] The nozzle can also be moved before the body is rotated and / or after the body has been rotated.

[0050] A design in which the body is tilted vertically relative to the horizontal is advantageous. A tilt angle of between 5° and 60° relative to the horizontal is advantageous.

[0051] An embodiment is advantageous according to which the first angle is n-360°, where n is a natural number.

[0052] Natural numbers are 1, 2, 3, 4, 5, 6, 7, ....

[0053] The body advantageously completes one full rotation. However, two or more full rotations are also possible. Rotations of less than 360° are also possible. An advantageous embodiment is one in which the second angle lies between -(n-360° + 1°) and -(n-360° + 10°), preferably -(n-360° + 5°), where n is a natural number.

[0054] This has the advantage of ensuring even coverage. It is intended to prevent some areas from being over-dripped with waterproofing material, which could lead to dripping. The dripping of waterproofing material should be avoided.

[0055] A particularly homogeneous distribution of the impregnation material can be achieved by an exemplary sequence of angles: 360°, -365°, +370°, ...

[0056] An embodiment is advantageous, according to which the body is moved alternately in the first direction of rotation by the first angle and in the second direction of rotation by the second angle, wherein the second angle is at least «2 = > (cg + 1°) and at most «2 = > (cg + 10°), preferably «2 = > (cg + 5°).

[0057] It is advantageous to move the body in this way during the sprinkling.

[0058] Current flows through the winding before and / or during and / or after the spraying.

[0059] The Joule heating of the coils beneficially warms the entire body. Heating with an oven is then no longer necessary, saving time and money. It also saves energy.

[0060] The body can be heated in this way before, during, and after impregnation. A preferred embodiment is one in which a three-phase winding is passed through by three-phase alternating current, while a single-phase winding is passed through by single-phase alternating current.

[0061] Using the example of a stator with a three-phase winding, the following steps are advantageously carried out: The stator's supply lines are connected to the connecting lines provided by an impregnation device. This can also be achieved, for example, using a terminal plate.

[0062] Current collection via sliding contacts is also possible. In this case, continuous rotation of the body is also possible.

[0063] However, since sliding contacts have many disadvantages, e.g. brush sparks, a design with permanently connected connecting cables, e.g. by means of flexible stranded conductors with a suitable cross-section, is preferred within the scope of the invention.

[0064] The cross-section of the stranded conductors is advantageously larger than the cross-section of the winding.

[0065] The connecting cables are connected or connectable to a power supply unit, which preferably provides power in the form of three-phase alternating current.

[0066] The three phases of the stator are energized, causing the windings to heat up. The windings are preferably constructed of copper.

[0067] The windings can be energized continuously. However, breaks are also possible.

[0068] Analogous to the example "stator", a rotor or a transformer or another electrical machine can also be impregnated. The object is further achieved by an impregnation device for impregnating a body carrying at least one winding, in particular for an electrical machine, in particular for carrying out the method according to one of the preceding claims, comprising:

[0069] - a drive with a drive shaft, wherein the drive is designed to move the body about a rotational axis, wherein the drive shaft has at least one fastening element for releasably connecting the body to the drive shaft,

[0070] - a dripping unit, wherein the dripping unit is designed to drip the body with an impregnating material,

[0071] - a connection unit, wherein the connection unit is designed to connect the winding to an electrical power supply.

[0072] The connection unit can have a clamping plate to which the winding ends can be clamped.

[0073] Alternatively or additionally, the connection unit can also comprise individual conductors that can be connected to the winding ends.

[0074] Alternatively or additionally, the connection unit can also include sliding contacts.

[0075] An advantageous design is one in which the drive is designed to be vertically tiltable in relation to the horizontal.

[0076] An advantageous embodiment is one in which the trickling unit comprises a dosing nozzle for discharging the impregnating material.

[0077] The problem can also be solved by a rotor and / or stator impregnated by such a process.

[0078] The invention offers the advantage that impregnation can be carried out in a resource-efficient manner, since the amount of resin dripped onto the body can be precisely and individually dosed, for example, in comparison to known dipping processes.

[0079] It is possible to use multi-component resin systems, as already disclosed in EP 3 872 962 A2.

[0080] These multicomponent resin systems have such a high reactivity when mixed that gelling and curing are possible at room temperature or only slightly elevated temperatures .

[0081] The problem is also solved by a software object that acts as a digital twin of a body carrying at least one winding, the body being impregnated by means of the method.

[0082] The object is further achieved by a method for generating a software object acting as a digital twin of a body carrying at least one winding, wherein the body is impregnated by means of the described method.

[0083] In the following, the invention is described and explained in more detail with reference to the exemplary embodiments shown in the figures.

[0084] It shows :

[0085] FIG 1 a dynamoelectric rotary machine,

[0086] FIG 2 and 3 a body,

[0087] FIG 4 an impregnation device,

[0088] FIG 5 the procedure,

[0089] FIGS 6 and 7 show a rotation, FIGS 8 to 11 show a process of absorbing the impregnating material,

[0090] FIGS 12 to 14 show a network,

[0091] FIG 15 a software object acting as a digital twin,

[0092] FIG 16 further possible arrangements of the microphone,

[0093] FIGS 17 and 18 Details and possible errors .

[0094] FIG 1 shows a dynamoelectric rotary machine 1 with a stator 2, a rotor 3 and a shaft 31.

[0095] The rotor and / or stator were impregnated using the described method.

[0096] FIG 2 shows a body 4 carrying a winding 41 .

[0097] The body 4 is, for example, the rotor 3 or the stator 2 shown in FIG. 1. However, other bodies carrying a winding 41 can also be impregnated by the method.

[0098] The body 4 is impregnated in the figure by being dripped with impregnating material 6, in particular resin or a resin-containing mixture, by means of a dosing nozzle 5.

[0099] The body 4 is moved around a rotation axis A before and / or during and / or after sprinkling.

[0100] Current flows through the winding 41 before and / or during and / or after the sprinkling.

[0101] This is achieved in the figure by means of connected stranded conductors LU, LV, LW. These are advantageously connected to a power supply unit (see reference numeral 25 in FIG. 4). The current flow and the associated heat loss heat up the body.

[0102] The reference symbol RI indicates that the body 4 is rotated by a first angle in a first direction of rotation, preferably in a positive direction of rotation. The reference symbol R2 indicates that the body is rotated by the negative first angle. This is illustrated in FIG. 6.

[0103] It is also possible for the body to be rotated by a second angle in a second direction of rotation, preferably in a negative direction. This is illustrated in FIG. 7.

[0104] It is advantageous during sprinkling if the body is moved alternately in the first direction of rotation by the first angle and in the second direction of rotation by the second angle, wherein the second angle is at least a2 = - (al + 1 °) and at most a2 = - (al + 10 °), preferably a2 = - (al + 5 °).

[0105] The figure shows a microphone 200, in particular an ultrasonic directional microphone. This is advantageously designed to detect sound waves 201 generated by partial discharges.

[0106] The microphone 200 can move on an axis C (marked 202).

[0107] The winding 41 is subjected to a voltage pulse, in particular during and / or after impregnation.

[0108] In the event of faulty impregnation and / or insufficient impregnation and / or a wire crossing (non-exhaustive list), a partial discharge caused by the voltage pulse is detected by the microphone 200. This is advantageously achieved by acoustically detecting the partial discharge using an ultrasonic directional microphone.

[0109] In order to detect all fault locations, it is advantageous if the microphone 200 is moved axially over the body 4 and thus over the winding 41.

[0110] In order to correct a detected error, it is advantageous to sprinkle a spot on the body where a partial discharge was detected again.

[0111] It is advantageous to apply a high-voltage pulse to a test object (i.e. the body, e.g. stator or rotor).

[0112] FIG. 3 shows the body 4 tilted vertically relative to the horizontal. A tilt angle ß of between 5° and 60° relative to the horizontal is advantageous.

[0113] A tilt angle ß that lies between 10° and 35° with respect to the horizontal is particularly good.

[0114] FIG 4 shows an impregnation device 10.

[0115] The impregnation device 10 for impregnating a body carrying at least one winding, in particular for an electrical machine 1, in particular for carrying out the method according to one of the preceding claims, according to FIG. 4, comprises: a drive 11 with a drive shaft 12, wherein the drive 11 is designed to move the body 4 about the rotation axis A. The drive shaft 12 has at least one fastening element 13 for releasably connecting the body 4 to the drive shaft 12.

[0116] The impregnation device 10 shown in the figure also has a dripping unit 51, wherein the dripping unit 51 is designed to drip the impregnation material 6 onto the body 4. In the figure, the dripping unit 51 has the dosing nozzle 5 and a reservoir 7 in which the impregnation material 6 is stored.

[0117] The trickling unit 51 can e.g. be moved along an axis B.

[0118] In addition, the impregnation device 10 shown has a connection unit 24, wherein the connection unit 24 is designed to connect the winding 41 to an electrical power supply. For this purpose, the power supply unit 25 is shown in the figure.

[0119] In the figure, winding 41 is connected to the power supply unit via the stranded conductors LU, LV, LW. In the figure, this is achieved by a terminal plate 23.

[0120] In this way, a current flow through the winding is enabled.

[0121] The stranded conductors are advantageously flexible.

[0122] The stranded conductors are advantageously long enough to be able to withstand e.g.

[0123] B. three full rotations of the body, the winding 41 connects to the power supply unit 25 and does not break off or become detached. They can wrap around the drive shaft 12 during rotation and rest against it.

[0124] Depending on the application, the stranded conductors are long enough to allow between one and ten full turns.

[0125] If the body 4 is moved, for example, in the opposite direction, the stranded conductors LU, LV, LW wound on the drive shaft 12 are unwound again. It is also possible to tap current from the power supply unit for the winding using sliding contacts. However, the embodiment shown in the figure is preferred.

[0126] The figure also shows a donor 8.

[0127] The figure shows an arm 20 and an arm 21 connected by a joint 22. This is an exemplary embodiment that allows vertical tilting of the drive 11 and the body 4 relative to the horizontal. Other shapes are also possible.

[0128] For example, a stator 2 or rotor 3 (see FIG. 1) is clamped onto the drive shaft 12 shown and secured by means of the fastening element 13. Other mounting devices are also possible. A mounting device designed to rotate the body 4 about its longitudinal axis is advantageous.

[0129] The impregnation material 6 is preferably liquid. In the case of a stator to be impregnated, for example, the impregnation material 6 is dripped onto the winding heads and can be distributed throughout the winding head without dripping and evenly due to the rotational movement. Due to the capillary forces that occur, the impregnation material can be advantageously drawn into existing grooves.

[0130] Since the stator is heated by the current supply, the flowability of the impregnating material 6, preferably the resin, is improved. Furthermore, gelling and curing of the impregnating material 6 are particularly well achieved.

[0131] FIG 5 shows the procedure.

[0132] In a process step S1, current flows through the body 4 (see FIG. 4). This heats the body 4. It is possible to wait a defined period of time before proceeding with process step S2. Alternatively, immediately afterward, in process step S2, impregnation material 6 is discharged via the dosing nozzle 5 to sprinkle the body 4.

[0133] The body 4 is rotated in the first direction of rotation RI in a process step S3 and can then be rotated in the second direction of rotation R2.

[0134] The sprinkling can now be complete and the discharge of the impregnating material can be stopped in a process step S4.

[0135] In a method step S5, the winding is subjected to a voltage pulse, whereby any partial discharge that occurs is detected by the microphone.

[0136] In a method step S 6 , a location on the body at which a partial discharge was detected or several locations can be sprayed again .

[0137] Curing can then take place.

[0138] Alternatively, partial discharge detection can occur during the dripping process. Then, in process step S4, the winding can be subjected to a voltage pulse, and any partial discharge that occurs can be detected by the microphone. In process step S5, a spot on the body where a partial discharge was detected, or even several spots, can be dripped again, and the dripping process can be stopped in process step S6.

[0139] However, the dosing nozzle 5 can also be moved while it is discharging impregnation material. The discharge of the impregnation material can also be stopped if the dosing nozzle is to be moved. A combination of heating the winding (the winding advantageously comprising copper) by the described current supply, the application of the impregnation material by trickling, and the pendulum movement of the body to be impregnated prevents the impregnation material from dripping. A homogeneous distribution of the impregnation material, for example in the winding head or, for example, in the slots of the rotor or stator, can thus be easily achieved.

[0140] In the process, a reversal speed, a position of the dosing nozzles, a temporary reduction of the dosing quantity before and during the reversal as well as a temporal variance of successive reversal processes can be varied - e.g. depending on the type and size of the body.

[0141] For example, the dosage can be maximized during a full rotation and then minimized during the reversal process to prevent dripping.

[0142] The reversal process can take place, for example, after every 360° (or whole multiples thereof) or after variable rotation angles (e.g. 1. 360°, 2. -365°, 3. +370°, ...) in order to ensure the most homogeneous distribution possible.

[0143] The connecting lines can also be designed to be so flexible and long that few or no reversals are necessary during the actual dosing process. The length and type of the connecting lines should be selected to minimize Joule losses in the connecting lines.

[0144] Particularly advantageous in this case are the described flexible stranded conductors with a suitable cross-section, which is, for example, significantly larger than the cross-section of the winding. However, other designs are also possible.

[0145] FIGS. 8 to 11 show the absorption curve of the impregnating material, in particular resin absorption. The abscissa indicates a time curve t, which includes the absorption of the impregnating material (see FIGS. 8 to 11) and crosslinking (see FIGS. 12 to 14). The ordinate indicates a capacitance 30, in particular an increase in capacitance in FIGS. 8 to 11 and a decrease in capacitance in FIGS. 12 to 14.

[0146] An increase in capacitance 30 between phases U and V, V and W and U and W is shown, see M1, as well as an increase in capacitance between U to earth, V to earth and W to earth (shown by Ground G), see M2.

[0147] The absorption of the impregnating material 6 begins at t1 in FIG. 1, in that the nozzle 5 applies the impregnating material 6, preferably drop by drop, to the winding 41 or sprinkles it onto the winding 41. The winding 41 is advantageously arranged at least partially in grooves of the body 4, in particular the laminated core. Winding heads are advantageously formed at an axial front end and at an axial rear end.

[0148] In addition, another nozzle 5a can apply impregnation material 6a to another end of the winding 41.

[0149] In FIGS. 9-11, it is visible that the winding has absorbed impregnation material 6. At t2, the winding heads are saturated, at t3, the impregnation flows into the slot exit, and at t4, the slots are saturated.

[0150] FIG 11 also shows that by contacting individual sheets 39 a better resolution is possible and thus a capacitance of U against earth, V against earth and W against earth can be determined more effectively.

[0151] The invention is advantageous because it enables the measurement and processing of the electrical capacitances between individual phases U, V, and W, or the respective capacitances between the aforementioned phases and the iron sheet (earth). From the information obtained from this, advantageously in real time, parameters such as the metered quantity, metering location (in particular the winding head inside and / or outside, slot exit, various phases), and winding temperature of the individual phases can be adjusted during the ongoing process.

[0152] A particular advantage is that trickle-feed technology, particularly the ability to precisely adjust the amount of resin to be introduced with temporal and spatial resolution, as well as the ability to directly and individually adjust the winding temperature via the connected lines, in combination with knowledge of the resin fill quantity, particularly within the winding heads and the individual slots, allows for a highly precise, component-specific process. Furthermore, energy and resources can be saved.

[0153] The measurement of the capacities can be divided into two areas, a dosing area (see FIG 8 to FIG 11) and a gelling or hardening area (FIG 12 to FIG 14).

[0154] During the metered addition of the impregnating material 6 or 6a, the air in the interstices of the winding, particularly in the interstices between the enameled wires, is advantageously displaced by the, preferably liquid, impregnating material. Due to its high dielectric number (>10), this advantageously gradually increases the measured capacitance.

[0155] Here, a differentiation of the measuring points is important for the distribution of the impregnation material, which is shown in the figures.

[0156] An increase in the phase-to-phase capacitance advantageously indicates the fill level of the impregnation material in the winding overhangs (resolved according to the individual regions of the winding overhang). An increase in the phase(s)-to-earth capacitance advantageously indicates the fill level in the individual slots. It is also possible to tap the earth electrode on each individual sheet 39 (see FIG. 11) with a small measuring tip. This can further improve the resolution within the slots.

[0157] By knowing which phase runs in which slot of the rotating stator, as well as in which areas of the winding head two of the three phases are adjacent to each other and thus significantly influence the capacitive structure, an optimal distribution of the impregnation material can be ensured in a targeted manner, in particular by synchronizing the rotation speed and thus the angular position of the critical areas with the dosage amount. By measuring temperature and capacitance simultaneously or in short sequences of, for example, five to ten seconds, e.g. between heating phases, a fill level distribution over time can be determined.

[0158] As the gelling or hardening of the distributed impregnation material, e.g. reactive resin, continues within the winding 41 (see FIGS. 12 to 14), the crosslinking advantageously leads to a reduction in the dielectric constant up to the final state of complete crosslinking, which, depending on the resin chemistry and the number and nature of the polar groups, has a dielectric constant advantageously between 2 and 5. This process is advantageously reflected in the measurement of the capacitances, whereby a measurement of the changing capacitances can be used to determine the degree of crosslinking and thus any remaining viscosity, which determines the time of the cycle in a trickle-coating system.

[0159] In particular, by means of the thermokinetic simulations, which are part of the European patent application with the application number 22183330 . 4, a process-related advantage can be generated by, for example, determining a necessary degree of gelation for each component individually during operation, which can vary depending on the component size and properties, and thus triggering component removal or catalyzing the curing reaction in a targeted manner via single-phase current supply.

[0160] FIGS 12, 13, and 14 show a reduction in capacity 30. The reduction in capacity is essentially a result of gelation (crosslinking).

[0161] In t5 (see FIGS 12 and 13) there is a beginning of cross-linking, in t6 a gelling point, in t7 there is complete cross-linking.

[0162] In the time window At56 , see FIG 14 , a drip-free stator is advantageously present, whereby this is particularly dependent on the cycle time and also on the variant.

[0163] Capacity thresholds can indicate the degree of crosslinking, allowing cycle times to be optimized in situ. This is particularly effective when a capacity profile is known throughout the crosslinking process in correlation with viscosity.

[0164] Since the impregnating material acts as a dielectric, preferably a liquid one, and gradually displaces air during the impregnation, the following applies:

[0165] Capacity ~ £0£ r Geometry constant s r of air is 1 , s r of liquid resin is advantageously between 10 and 15 .

[0166] The combination of trickling, i.e. in particular the targeted dosing of a quantity of resin into specific areas of the stator, with the option of line connection (also called reverse trickling), offers the possibility of carrying out various measurements on the stator or another body with a winding during the ongoing process and of achieving targeted or partial heating of the winding. This means that for the first time, individual impregnation and curing can be carried out in a so-called one-piece flow, independent of variance. This offers the possibility of material and energy savings as well as cycle time optimization and thus productivity in production.

[0167] FIG. 15 shows a software object 400 functioning as a digital twin of a body 4 carrying at least one winding 41. The body 4 is impregnated by means of the described method.

[0168] A digital twin is advantageously a digital image or a data-technical equivalent of the body 4, for example the rotor and / or the stator.

[0169] The digital twin is thus advantageously a data set that directly or indirectly includes all the data 401 necessary to describe the relevant properties of the body 4. The properties are, for example, dimensions of the body.

[0170] The digital twin is particularly advantageous for the impregnation process. It allows for an image of defective areas to be created and thus targeted improvements to be made.

[0171] Other variables can also be taken into account. If the body 4 is dripped with an impregnating material 6, preferably one containing resin, and a capacitance 30 between two phases of the winding is determined and / or a capacitance 30 between a phase of the winding 41 against earth potential G is determined and an amount of impregnating material absorbed is determined by a change in the capacitance 30, the body 4 can be moved about an axis of rotation A before and / or during and / or after the dripping, in particular in order to distribute the impregnating material well. The impregnating material can thus be easily drawn into grooves, for example.

[0172] The digital twin makes it possible to determine how long the dripping should continue, whether certain areas should be dripped again, or whether a rotational movement is necessary to achieve good results. Furthermore, the digital twin can provide information about the dosage amount and / or dosage location, and the amount of energy required to feed into the winding to change the winding temperature.

[0173] For example, a control system can be instructed to improve impregnation.

[0174] FIG. 16 shows further possible arrangements of the microphone. Alternatively or additionally, a microphone 200a and / or a microphone 200b can be arranged at the locations shown to better detect errors. The directions of movement 202a and 202b are also shown.

[0175] Furthermore, details of the impregnated body are shown, also in FIGS. 17 and 18. Examples of defects include inadequate impregnation 300 or unfavorable wire crossing 301 (e.g., different phases U, V, W, or low and high turns of the same phase). This is advantageously detected by axial scanning of the body by the ultrasonic directional microphones. The partial discharges can be easily localized by the resulting ultrasound. This allows for targeted replenishment.

[0176] For example, the defect of inadequate impregnation 300 is remedied by closing the resin-depleted region (see 302). In the case of unfavorable wire crossings 301, increasing the resin quantity and thus the impregnation quality in the critical region (see 303) is advantageous.

Claims

Patent claims 1. Method for impregnating a body (4) carrying at least one winding (41), in particular for an electrical Machine (1), for example for a rotor (3) or stator (2), wherein the body (4) is sprinkled with an impregnating material (6), preferably comprising resin, wherein the winding is subjected to a voltage pulse during and / or after the impregnation, wherein an occurring partial discharge is detected by a microphone.

2. Method according to claim 1, wherein the occurring partial discharge is detected acoustically by an ultrasonic directional microphone.

3. The method according to claim 2, wherein the ultrasonic directional microphone is moved axially over the body.

4. Method according to one of the preceding claims, wherein a location of the body at which a partial discharge was detected is sprinkled again.

5. Method according to one of the preceding claims, wherein a capacitance (30) between two phases (U, V, W) of the winding (41) is determined and / or wherein a capacitance (30) between one phase (U, V, W) of the winding (41) against earth potential (G) is determined, wherein an amount of impregnation material taken up is determined by a change in the capacitance (30).

6. Method according to one of the preceding claims, wherein the body (4) is moved about a rotation axis (A) before and / or during and / or after the sprinkling, wherein the winding (41) is passed through by current before and / or during and / or after the sprinkling in order to heat the winding, wherein a dosage amount and / or a dosage location and / or a supply of energy into the winding for changing a winding temperature, in particular the individual phases, depending on the determined capacity.

7. The method according to claim 6, wherein the capacity is determined cyclically.

8. Method according to one of the preceding claims, wherein the body (4) is rotated by a first angle (cg) in a first direction of rotation, preferably in a positive direction of rotation (RI), wherein the body (4) is rotated by the negative first angle -(cg) or a second angle («2) in a second direction of rotation (R2), preferably in a negative direction of rotation.

9. Method according to one of the preceding claims, wherein the body (4) is moved in the first direction of rotation (RI) at a first rotational speed, wherein the body (4) is moved in the second direction of rotation (R2) at a second rotational speed, wherein the first rotational speed is greater than the second rotational speed.

10. Method according to one of the preceding claims, wherein the rotational speed is adjusted depending on the determined capacity.

11. Method according to one of the preceding claims, wherein the impregnating material (6) is directed onto the body (4) or in the direction of the body (4) by means of a dosing nozzle (5).

12. Method according to one of the preceding claims, wherein the impregnating material (6) is directed to an axial end of the body (4).

13. Method according to one of the preceding claims, wherein the dosing nozzle (5) is moved, preferably parallel to the body (4).

14. Method according to one of the preceding claims, wherein the body (4) is tilted vertically with respect to the horizontal.

15. Impregnation device (10) for impregnating a body (4) carrying at least one winding (41), in particular for an electrical machine (1), in particular for carrying out the method according to one of the preceding claims, comprising: - a drive (11) with a drive shaft (12), wherein the drive (11) is designed to move the body (4) about a rotation axis (A), wherein the drive shaft (12) has at least one fastening element (13) for releasably connecting the body (4) to the drive shaft (12), - a dripping unit (51), wherein the dripping unit (51) is designed to drip the body (4) with an impregnating material (6), - a connection unit (24), wherein the connection unit (24) is designed to connect the winding (41) to an electrical power supply (25), - a microphone for detecting a partial discharge.

16. Body comprising at least one winding, in particular rotor (3) and / or stator (2), impregnated by a method according to one of claims 1 to 14.

17. A software object (400) functioning as a digital twin of a body (4) carrying at least one winding (41), wherein the body (4) is impregnated by means of a method according to one of claims 1 to 14.

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