Voltage loading device and motor bearing electrocorrosion test equipment

Abstract

The invention provides a voltage loading device and motor bearing electrocorrosion test equipment, and the voltage loading device comprises a voltage loading circuit, a bearing, a rotating shaft, and a carbon brush. The bearing is mounted on the rotating shaft; the carbon brush is connected with the rotating shaft; the voltage loading circuit comprises an AC / DC power supply, a first capacitor, a second capacitor and a third capacitor, the first capacitor, the second capacitor and the third capacitor form a capacitor branch, the capacitor branch is electrically connected with the AC / DC power supply and the outer ring of the bearing, the first capacitor is used for simulating parasitic capacitance between the motor winding and the stator core, and the second capacitor is used for simulating parasitic capacitance between the motor winding and the stator core. The second capacitor is used for simulating parasitic capacitance between the motor winding and the rotor core, and the third capacitor is used for simulating capacitance between the stator core and the rotor core. The actual working circuit of motor bearing electrocorrosion can be simulated, so that the voltage and the discharge current of the bearing can be accurately simulated, and the accuracy of the motor bearing electrocorrosion test can be conveniently improved.

Description

Technical Field

[0001] The present application relates to the field of motor testing, and in particular to a voltage loading device and motor bearing electrical corrosion testing equipment. Background Art

[0002] In the prior art, during the electrical corrosion test on a bearing bench, the positive and negative electrodes of the voltage source are connected to the inner and outer rings of the bearing respectively, and the inner and outer rings of the bearing rotate relative to each other. When the voltage is greater than a certain value, an EDM discharge current passes through the bearing, thereby simulating the electrical corrosion process of the bearing and obtaining the test results.

[0003] However, the prior art has the following disadvantages:

[0004] The circuit formed by connecting the positive and negative electrodes of the voltage source to the inner and outer rings of the bearing respectively is quite different from the actual working circuit of the motor bearing electrical corrosion. When the bearing is discharged inside, the corrosion current is only affected by the contact internal resistance and the maximum output current of the power supply. It cannot accurately simulate the voltage and discharge current of the bearing. Accordingly, the accuracy of the motor bearing electrical corrosion test results is also low. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a voltage loading device and a motor bearing electrical corrosion test equipment for simulating the actual working circuit of motor bearing electrical corrosion, thereby accurately simulating the voltage and discharge current of the bearing, thereby facilitating improving the accuracy of the motor bearing electrical corrosion test.

[0006] In a first aspect, the present invention provides a voltage loading device, the device comprising a voltage loading circuit, a bearing, a rotating shaft, and a carbon brush;

[0007] The bearing is mounted on the rotating shaft, and the carbon brush is connected to the rotating shaft;

[0008] The positive terminal of the voltage loading circuit is connected to the outer ring of the bearing, and the negative terminal of the voltage loading circuit is connected to the carbon brush to form a test circuit;

[0009] The voltage loading circuit includes an AC / DC power supply, a first capacitor, a second capacitor, and a third capacitor. The first capacitor, the second capacitor, and the third capacitor form a capacitor branch. The capacitor branch is electrically connected to the AC / DC power supply and the outer ring of the bearing. The first capacitor is used to simulate the parasitic capacitance between the motor winding and the stator core, the second capacitor is used to simulate the parasitic capacitance between the motor winding and the rotor core, and the third capacitor is used to simulate the capacitance between the stator and rotor cores.

[0010] The voltage loading device of the first aspect of the present application can simulate the parasitic capacitance between the motor winding and the stator core through the first capacitor, the second capacitor, and the third capacitor. The second capacitor is used to simulate the parasitic capacitance between the motor winding and the rotor core, and the third capacitor is used to simulate the capacitance between the stator and rotor cores. This can further simulate the voltage and discharge current of the bearing in actual working conditions, thereby facilitating obtaining more accurate electrical corrosion test results of the motor bearings based on the voltage and discharge current of the bearing in actual working conditions.

[0011] In an optional embodiment, the first capacitor is a variable capacitor, wherein a value of the first capacitor is determined based on a model of the motor.

[0012] This optional implementation manner sets the first capacitor as a variable capacitor, and further determines the value of the first capacitor based on the model of the motor. In this way, the parasitic capacitance between the motor winding and the stator core of motors of different models can be simulated.

[0013] In an optional embodiment, the second capacitor is a variable capacitor, wherein a value of the second capacitor is determined based on a signal from a motor.

[0014] This optional implementation sets the second capacitor as a variable capacitor, and the value of the second capacitor can be determined based on the model of the motor. In this way, the parasitic capacitance between the motor winding and the rotor core of motors of different models can be simulated.

[0015] In an optional implementation, the third capacitor is a variable capacitor, and a value of the third capacitor is determined based on a model of the motor.

[0016] This optional implementation manner sets the third capacitor as a variable capacitor, and further determines the value of the third capacitor based on the model of the motor. In this way, the capacitance between the stator and rotor cores of motors of different models can be simulated.

[0017] In an optional implementation, the voltage loading circuit further includes a switching switch, wherein the switching switch is electrically connected to the AC / DC power supply, and the switching switch is used to shield the capacitor branch.

[0018] In an optional embodiment, the working mode of the AC / DC power supply includes a DC mode and an AC mode, wherein when the working mode of the AC / DC power supply is the DC mode, the switching switch is in a closed state, and the AC / DC power supply is directly connected to the outer ring of the bearing.

[0019] This optional implementation manner can connect the AC / DC power supply directly to the outer ring of the bearing when the working mode of the AC / DC power supply is the DC mode.

[0020] This optional implementation manner can shield the capacitor branch by using a switching switch when the working mode of the AC / DC power supply is the DC mode, thereby enabling the voltage applied to the bearing to be a stable voltage.

[0021] In this optional implementation mode, when the working mode of the AC / DC power supply is the AC mode, the AC / DC power supply can be replaced by a variable frequency power module such as IGBT, SiC, GaN, etc.

[0022] In an optional implementation, when the working mode of the AC / DC power supply is the AC mode, the switching switch is in an off state, and the AC / DC power supply supplies power to the bearing through the capacitor series-parallel circuit.

[0023] In this optional implementation mode, when the working mode of the AC / DC power supply is the AC mode, the switching switch is turned off so that the AC / DC power supply supplies power to the bearing through the capacitor series-parallel circuit.

[0024] In an optional implementation, the waveform output by the AC / DC power supply includes at least a DC wave, a sine wave, a triangle wave, a square wave, and a step wave.

[0025] This optional implementation can enable the AC / DC power supply to output DC wave, sine wave, triangle wave, square wave, or step wave, thereby meeting the test requirements.

[0026] In a second aspect, the present invention provides a motor bearing electrical corrosion test device, the device comprising a voltage loading device as described in any one of the aforementioned embodiments.

[0027] The motor bearing electrical corrosion test equipment of the present application can perform electrical corrosion tests on motor bearings through a voltage loading device under the premise of simulating the parasitic capacitance between the motor winding and the stator core, simulating the parasitic capacitance between the motor winding and the rotor core, and simulating the capacitance between the stator and rotor cores, thereby improving the accuracy of the motor bearing electrical corrosion test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 is a schematic diagram of a voltage loading device disclosed in an embodiment of the present application;

[0030] Figure 2The embodiment of the present application discloses a common-mode voltage waveform diagram of a motor;

[0031] Figure 3 It is a schematic diagram of an electric corrosion circuit of a motor bearing disclosed in an embodiment of the present application;

[0032] Figure 4 This is the first motor bearing electrical corrosion equivalent circuit diagram disclosed in the embodiment of the present application.

[0033] Icon: voltage loading circuit 1, bearing 2, rotating shaft 3, carbon brush 4, AC / DC power supply V, first capacitor C1, second capacitor C2, third capacitor C3, stator core 100, stator winding Vn, rotor 200, rotor shaft 300, bearing component 400, bearing outer ring 500, parasitic capacitance Cwf between winding and stator core, parasitic capacitance Cwr between winding and rotor core, capacitance Crf between stator and rotor core. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0035] Embodiment 1

[0036] See also Figure 1 , Figure 1 Schematic diagram of a voltage loading device disclosed in an embodiment of the present application. Figure 1 As shown, the voltage loading device includes a voltage loading circuit 1, a bearing 2, a rotating shaft 3, and a carbon brush 4, wherein the electric bearing is mounted on the rotating shaft, and the carbon brush is connected to the rotating shaft. Further, the positive terminal of the voltage loading circuit is connected to the outer ring of the bearing, and the negative terminal of the voltage loading circuit is connected to the carbon brush to form a test circuit. Further, the voltage loading circuit includes an AC / DC power supply V, a first capacitor C1, a second capacitor C2, and a third capacitor C3, wherein the first capacitor forms a capacitor branch with the second capacitor and the third capacitor, and the capacitor branch is electrically connected to the AC / DC power supply and the outer ring of the bearing, wherein the first capacitor is used to simulate the parasitic capacitance between the motor winding and the stator core, the second capacitor is used to simulate the parasitic capacitance between the motor winding and the rotor core, and the third capacitor is used to simulate the capacitance between the stator and rotor cores.

[0037] The voltage loading device of the embodiment of the present application can simulate the parasitic capacitance between the motor winding and the stator core through the first capacitor, the second capacitor, and the third capacitor. The second capacitor is used to simulate the parasitic capacitance between the motor winding and the rotor core, and the third capacitor is used to simulate the capacitance between the stator and the rotor core. This can further simulate the voltage and discharge current of the bearing in actual working conditions, thereby facilitating obtaining more accurate electrical corrosion test results of the motor bearings based on the voltage and discharge current of the bearing in actual working conditions.

[0038] The principle of the embodiment of the present application to obtain more accurate motor bearing electrical corrosion test results by simulating the voltage and discharge current of the bearing in actual working conditions is:

[0039] In an induction motor system powered by a motor driver, the source of the motor's shaft voltage and bearing current lies in the motor's common-mode voltage. The motor's common-mode voltage refers to the voltage between the neutral point of the three-phase load and the ground. When the motor's stator winding is connected to a three-phase two-level inverter, the inverter has three switching actions at any given moment, forming eight switching states, so that the sum of the inverter output voltage Vao+Vbo+Vco is usually not zero. The common-mode voltage Vn of the neutral point of the motor's three-phase stator winding is Vao+Vbo+Vco, so there is a common-mode voltage at the motor winding end such as Figure 2 The step waveform shown, where Figure 2 This is a common mode voltage waveform diagram of a motor disclosed in an embodiment of the present application. Figure 3 , Figure 3 Schematic diagram of a motor bearing electrocorrosion circuit disclosed in the embodiment of the present application. Figure 3 As shown, in an actual motor, the motor stator core 100 is grounded through the housing, the stator winding Vn is wound on the stator core 100, the motor rotor 200 is assembled on the rotor shaft 300, the rotor shaft 300 is supported on the housing through the bearing component 400, and the bearing outer ring 500 is grounded through the housing. In the motor structure, there are parasitic capacitances Cwf between the winding and the stator core, parasitic capacitances Cwr between the winding and the rotor core, and capacitances Crf between the stator and rotor cores, wherein the parasitic capacitances Cwf between the winding and the stator core include parasitic capacitances Cwf1 and Cwf2. Therefore, the AC common-mode voltage of the stator winding is not directly applied to the bearing, but is coupled to the rotor and the bearing through the parasitic capacitance Cwr, and the generated rotor shaft voltage is the bearing voltage. In addition, the common-mode voltage of the winding can also be coupled to the housing through Cwf and Crf, wherein the equivalent circuit diagram of the motor bearing electrical corrosion is as shown in FIG. Figure 4 As shown, Figure 4 This is the first motor bearing electrical corrosion equivalent circuit diagram disclosed in the embodiment of the present application.

[0040] Furthermore, when the bearing oil film breaks down, the on-current of the bearing is not only related to the shaft voltage and the bearing contact internal resistance, but also affected by the power supply voltage, the amount of electricity of the parasitic capacitance (Cwf, Cwr, Crf) and the charge and discharge state. Only by the shaft voltage simulation, the bearing electrical corrosion process cannot be truly reflected. The embodiment of the present application achieves the goal of truly simulating the bearing current corrosion process by simulating the electrical structure of the motor. By adjusting the capacity of the variable capacitors C1, C2, and C3, the parasitic capacitance (Cwf, Cwr, Crf) of motors of different models can be simulated to flexibly meet the test requirements. In addition, when the power supply applies a DC voltage, the bearing pressure drop is also unstable due to the unstable oil film state (bearing capacitance) of the bearing.

[0041] In an optional embodiment, the first capacitor is a variable capacitor, wherein a value of the first capacitor is determined based on a model of the motor.

[0042] This optional implementation manner sets the first capacitor as a variable capacitor, and further determines the value of the first capacitor based on the model of the motor. In this way, the parasitic capacitance between the motor winding and the stator core of motors of different models can be simulated.

[0043] In an optional embodiment, the second capacitor is a variable capacitor, wherein a value of the second capacitor is determined based on a signal from the motor.

[0044] This optional implementation sets the second capacitor as a variable capacitor, and the value of the second capacitor can be determined based on the model of the motor. In this way, the parasitic capacitance between the motor winding and the rotor core of motors of different models can be simulated.

[0045] In an optional embodiment, the third capacitor is a variable capacitor, and the value of the third capacitor is determined based on the model of the motor.

[0046] This optional implementation manner sets the third capacitor as a variable capacitor, and further determines the value of the third capacitor based on the model of the motor. In this way, the capacitance between the stator and rotor cores of motors of different models can be simulated.

[0047] In an optional implementation, the voltage loading circuit further includes a switching switch, wherein the switching switch is electrically connected to the AC and DC power supplies, and the switching switch is used to shield the capacitor branch.

[0048] This optional implementation manner can shield the capacitor branch by using a switching switch when the working mode of the AC / DC power supply is the DC mode, thereby enabling the voltage applied to the bearing to be a stable voltage.

[0049] In some applications, when the breakdown voltage of the bearing oil film needs to be tested, stable results cannot be obtained. Figure 1As shown in the figure, a switching switch K is added between the power supply and the bearing. Closing this switch can shield the capacitor branch, and the test voltage applied to the bearing is a stable value.

[0050] In an optional embodiment, the working mode of the AC / DC power supply includes a DC mode and an AC mode, wherein when the working mode of the AC / DC power supply is the DC mode, the switching switch is in a closed state, and the AC / DC power supply is directly connected to the outer ring of the bearing.

[0051] This optional implementation manner can connect the AC / DC power supply directly to the outer ring of the bearing when the working mode of the AC / DC power supply is the DC mode.

[0052] In an optional implementation, when the working mode of the AC / DC power supply is the AC mode, the switching switch is in an off state, and the AC / DC power supply supplies power to the bearing through a capacitor series-parallel circuit.

[0053] In this optional implementation mode, when the working mode of the AC / DC power supply is the AC mode, the switching switch is turned off so that the AC / DC power supply supplies power to the bearing through a capacitor series-parallel circuit.

[0054] In an optional implementation manner, the waveform output by the AC / DC power supply includes at least a DC wave, a sine wave, a triangle wave, a square wave, and a step wave.

[0055] This optional implementation can enable the AC / DC power supply to output DC wave, sine wave, triangle wave, square wave, or step wave, thereby meeting the test requirements.

[0056] In this optional implementation mode, when the working mode of the AC / DC power supply is the AC mode, the AC / DC power supply can be replaced by a variable frequency power module such as IGBT, SiC, GaN, etc.

[0057] In addition, an embodiment of the present application also provides a motor bearing electrical corrosion test device, which includes a voltage loading device as described in any of the aforementioned embodiments.

[0058] The motor bearing electrical corrosion test equipment of the present application can perform electrical corrosion tests on motor bearings through a voltage loading device under the premise of simulating the parasitic capacitance between the motor winding and the stator core, simulating the parasitic capacitance between the motor winding and the rotor core, and simulating the capacitance between the stator and rotor cores, thereby improving the accuracy of the motor bearing electrical corrosion test results.

[0059] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0060] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0061] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0062] It should be noted that if the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can essentially be embodied in the form of a software product, or in other words, the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM) random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0063] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0064] The above are only embodiments of the present application and are not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A voltage loading device, characterized in that: The device includes a voltage loading circuit, a bearing, a rotating shaft, and a carbon brush; The bearing is mounted on the rotating shaft, and the carbon brush is connected to the rotating shaft; The positive terminal of the voltage loading circuit is connected to the outer ring of the bearing, and the negative terminal of the voltage loading circuit is connected to the carbon brush to form a test circuit; The voltage loading circuit includes an AC / DC power supply, a first capacitor, a second capacitor, and a third capacitor. The first capacitor, the second capacitor, and the third capacitor form a capacitor branch. The capacitor branch is electrically connected to the AC / DC power supply and the outer ring of the bearing. The first capacitor is used to simulate the parasitic capacitance between the motor winding and the stator core, the second capacitor is used to simulate the parasitic capacitance between the motor winding and the rotor core, and the third capacitor is used to simulate the capacitance between the stator and rotor cores.

2. The device according to claim 1, characterized in that The first capacitor is a variable capacitor, wherein a value of the first capacitor is determined based on a model of the motor.

3. The device according to claim 1, characterized in that The second capacitor is a variable capacitor, wherein a value of the second capacitor is determined based on a signal of the motor.

4. The device according to claim 1, characterized in that The third capacitor is a variable capacitor, and a value of the third capacitor is determined based on a model of the motor.

5. The device according to claim 1, characterized in that The voltage loading circuit further includes a switching switch, wherein the switching switch is electrically connected to the AC / DC power supply, and the switching switch is used to shield the capacitor branch.

6. The device according to claim 5, characterized in that The working modes of the AC / DC power supply include a DC mode and an AC mode, wherein when the working mode of the AC / DC power supply is the DC mode, the switching switch is in a closed state, and the AC / DC power supply is directly connected to the outer ring of the bearing.

7. The device according to claim 6, characterized in that When the working mode of the AC / DC power supply is the AC mode, the switching switch is in an off state, and the AC / DC power supply supplies power to the bearing through a capacitor series-parallel circuit.

8. The device according to claim 6, characterized in that The waveform output by the AC / DC power supply at least includes a DC wave, a sine wave, a triangle wave, a square wave, and a step wave.

9. The device according to claim 6, characterized in that When the AC / DC power source is in the AC mode, a variable frequency power module such as IGBT, SiC, GaN, etc. is used instead.

10. A motor bearing electrical corrosion test equipment, characterized in that: The device comprises a voltage loading device as described in any one of claims 1-9.

Images