Integrated insulation inspection system including conductive brush and voltage and current balancing circuit

Abstract

An insulation inspection system includes: a conductive brush arranged to brush over an insulation portion of a part to be inspected; voltage and current balancing circuits connected to the conductive brush, wherein each voltage and current balancing circuit is configured to detect a short circuit between one or more bristles of the conductive brush and a bare conductive element of the inspected part; and a control module configured to detect a defect in an insulating material of the part in response to the detected short circuit.

Description

Technical Field

[0001] The present disclosure relates to a continuity testing system, and more particularly to an insulation inspection system for inspecting stator windings and other electrical components. Background Art

[0002] The information provided in this section is for the purpose of generally introducing the background of the present disclosure. To the extent of the work of the currently named inventors in this section, and aspects that may not otherwise constitute prior art at the time of filing, are neither expressly nor implicitly admitted as prior art against the present disclosure.

[0003] Electric vehicles and hybrid vehicles include traction motors for propulsion purposes. Each traction motor includes a stator and a rotor, with the stator and rotor having respective windings and conductive bars. The windings and / or conductive bars may be insulated (e.g., having an external insulation coating). During manufacturing (including the formation and assembly of parts and components), the insulation coating may not be formed correctly, or there may be nicks, scratches, wear, etc. This may result in partial loss and / or removal of the insulation coating, thereby exposing the conductive elements. Such exposure may cause short circuits, affect motor performance, and / or shorten the motor life. Summary of the Invention

[0004] Disclosed is an insulation inspection system, comprising: a conductive brush arranged to brush over an insulated portion of a part to be inspected; a voltage and current balance circuit connected to the conductive brush, wherein each voltage and current balance circuit is configured to detect a short circuit between one or more bristles of the conductive brush and an exposed conductive element of the part to be inspected; and a control module configured to detect a defect in the insulating material of the part to be inspected in response to the detected short circuit.

[0005] In other features, the insulation inspection system further includes an analog-to-digital converter configured to receive an analog signal output of the voltage and current balance circuit.

[0006] In other features, the control module is configured to i) simultaneously monitor the digital output of the analog-to-digital converter, and ii) simultaneously determine whether there is a defect at the part position of each conductive brush.

[0007] In other features, the control module is configured to i) track the position of each conductive brush relative to the part when the part moves relative to the conductive brush, and ii) determine the position of the detected defect based on the tracked position of the respective conductive brush relative to the part.

[0008] In other features, the control module is configured to i) track the position of each conductive brush relative to the part when the conductive brush moves relative to the part, and ii) determine the position of the detected defect based on the tracked position of the respective conductive brush relative to the part.

[0009] Among other features, the insulation inspection system further includes a display. The control module is configured to indicate a detected defect on the display.

[0010] Among other features, the insulation inspection system further includes an audio device. The control module is configured to indicate a detected defect through the audio device.

[0011] Among other features, each voltage and current balance circuit includes a pair of resistors and a capacitor.

[0012] Among other features, the insulation inspection system further includes an analog-to-digital converter. Each analog-to-digital converter includes a set of input terminals. Each voltage and current balance circuit includes a pair of resistors and respective capacitors that are connected in series between two terminals of a set of input terminals of a corresponding one of the analog-to-digital converters.

[0013] Among other features, the pair of resistors of each voltage and current balance circuit includes a first resistor and a second resistor. The set of input terminals of each analog-to-digital converter includes a positive terminal, a negative terminal, and a common terminal. The first resistor of each pair of resistors includes i) a first end connected to a corresponding one of the positive terminals and connected to a corresponding one of the conducting brushes, and ii) a second end connected to a first end of the respective capacitor. The second resistor includes i) a first end connected to a corresponding one of the common terminals, and ii) a second end connected to a second end of the respective capacitor and connected to the second end of the part.

[0014] Among other features, for each voltage and current balance circuit: the first end of the respective capacitor is connected to the positive terminal of the power supply; and the second end of the respective capacitor is connected to the negative terminal of the power supply.

[0015] Among other features, for each voltage and current balance circuit, leads are connected between i) the negative terminal of the voltage and current balance circuit, the second end of the second resistor, and the second end of the respective capacitor, and ii) one or more three-phase contacts of the part.

[0016] Among other features, the capacitors of the voltage and current balance circuits are connected in parallel and connected to the same power supply.

[0017] Among other features, one end of each capacitor is connected to a lead and the negative terminal of the same power supply. The lead is connected to the part.

[0018] Among other features, the insulation inspection system further includes at least one motor configured to perform at least one of the following operations: i) move a part relative to a conductive brush, and ii) move one or more conductive brushes relative to the part. The control module is configured to i) control at least one motor to follow a movement profile, and ii) detect a defect in the insulating material of the part during the movement of at least one of the part and one or more conductive brushes due to a short circuit between one or more conductive bristles of the conductive brush and an exposed conductive element of the part at the defect location.

[0019] Among other features, the insulation inspection system further includes: a frame; and a support mounted on the frame and configured to hold the part relative to the conductive brush. The conductive brush is mounted on the frame relative to the part.

[0020] Among other features, an insulation inspection method is disclosed, which includes: connecting leads to the part to be inspected; at least one of the following: i) moving the part relative to the conductive brush, and ii) moving the conductive brush relative to the part; when performing at least one of the following operations: i) moving the part relative to the conductive brush, and ii) moving the conductive brush relative to the part, brushing the insulating material of the part with the conductive brush; detecting at least one short circuit between one or more bristles of the conductive brush and an exposed conductive element of the part by a voltage and current balance circuit, wherein the voltage and current balance circuit is connected to the conductive brush; and in response to the detected at least one short circuit, detecting at least one defect in the insulating material of the part.

[0021] Among other features, the insulation inspection method further includes: compiling the data collected via the voltage and current balance circuit and generating a report including the compiled data; and presenting the report.

[0022] Among other features, the presentation of the report includes: displaying the compiled data, generating an audible alarm, or transmitting the compiled data to a network device.

[0023] Among other features, the insulation inspection method further includes, after detecting a defect, removing at least one conductive brush used to detect the defect from the part so as to return the at least one conductive brush to a nominal voltage before using the at least one conductive brush again to detect another defect.

[0024] The present invention provides the following technical solutions:

[0025] 1. An insulation inspection system, comprising:

[0026] A plurality of conductive brushes arranged to brush an insulating portion of the part to be inspected;

[0027] A plurality of voltage and current balancing circuits connected to a plurality of conductive brushes, wherein each of the plurality of voltage and current balancing circuits is configured to detect a short circuit between one or more bristles of the plurality of conductive brushes and an exposed conductive element of a part; and

[0028] A control module configured to detect a defect in an insulating material of a part in response to a detected short circuit.

[0029] 2. The insulation inspection system according to aspect 1, further comprising a plurality of analog-to-digital converters configured to receive analog signal outputs of the plurality of voltage and current balancing circuits.

[0030] 3. The insulation inspection system according to aspect 2, wherein the control module is configured to i) simultaneously monitor digital outputs of the plurality of analog-to-digital converters, and ii) simultaneously determine whether there is a defect at the part location of each of the plurality of conductive brushes.

[0031] 4. The insulation inspection system according to aspect 1, wherein the control module is configured to i) track the position of each of the plurality of conductive brushes relative to the part when the part moves relative to the plurality of conductive brushes, and ii) determine the location of a detected defect based on the tracked position of a corresponding one of the plurality of conductive brushes relative to the part.

[0032] 5. The insulation inspection system according to aspect 1, wherein the control module is configured to i) track the position of each of the plurality of conductive brushes relative to the part when the plurality of conductive brushes move relative to the part, and ii) determine the location of a detected defect based on the tracked position of a corresponding one of the plurality of conductive brushes relative to the part.

[0033] 6. The insulation inspection system according to aspect 1, further comprising a display,

[0034] wherein the control module is configured to indicate a detected defect on the display.

[0035] 7. The insulation inspection system according to aspect 1, further comprising an audio device,

[0036] wherein the control module is configured to indicate a detected defect through the audio device.

[0037] 8. The insulation inspection system according to aspect 1, wherein each of the plurality of voltage and current balancing circuits includes a pair of resistors and a capacitor.

[0038] 9. The insulation inspection system according to aspect 1, further comprising a plurality of analog-to-digital converters, wherein:

[0039] each of the plurality of analog-to-digital converters includes a set of input terminals; and

[0040] Each of the plurality of voltage and current balancing circuits includes a pair of resistors and respective capacitors, the pair of resistors and the respective capacitors being connected in series between two terminals of a respective one of a set of input terminals of a plurality of analog-to-digital converters.

[0041] 10. The insulation inspection system according to aspect 9, wherein:

[0042] The pair of resistors of each of the plurality of voltage and current balancing circuits includes a first resistor and a second resistor;

[0043] The set of input terminals of each of the plurality of analog-to-digital converters includes a positive terminal, a negative terminal, and a common terminal;

[0044] The first resistor of each pair of resistors includes i) a first end connected to a respective one of the positive terminals and to a respective one of a plurality of conducting brushes, and ii) a second end connected to the first end of the respective capacitor; and

[0045] The second resistor includes i) a first end connected to a respective one of the common terminals, and ii) a second end connected to the second end of the respective capacitor and to the second end of the part.

[0046] 11. The insulation inspection system according to aspect 10, wherein, for each of the plurality of voltage and current balancing circuits:

[0047] The first end of the respective capacitor is connected to the positive terminal of the power supply; and

[0048] The second end of the respective capacitor is connected to the negative terminal of the power supply.

[0049] 12. The insulation inspection system according to aspect 10, wherein, for each of the plurality of voltage and current balancing circuits, leads are connected between i) the negative terminal of the voltage and current balancing circuit, the second end of the second resistor, and the second end of the respective capacitor, and ii) one or more three-phase contacts of the part.

[0050] 13. The insulation inspection system according to aspect 10, wherein the capacitors of the plurality of voltage and current balancing circuits are connected in parallel and connected to the same power supply.

[0051] 14. The insulation inspection system according to aspect 10, wherein:

[0052] One end of each of the capacitors is connected to a lead and the negative terminal of the same power supply; and

[0053] The lead is connected to the part.

[0054] 15. The insulation inspection system according to Solution 1 further includes at least one motor configured to perform at least one of the following operations: i) moving the part relative to the plurality of conductive brushes, and ii) moving one or more of the plurality of conductive brushes relative to the part.

[0055] Wherein, the control module is configured to i) control at least one motor to follow a motion profile, and ii) detect a defect in the insulating material of the part during the movement of at least one of the part and one or more of the plurality of conductive brushes due to a short circuit between one or more conductive bristles of the plurality of conductive brushes and the exposed conductive element of the part at the defect location.

[0056] 16. The insulation inspection system according to Solution 1 further includes:

[0057] A frame; and

[0058] A support member mounted on the frame and configured to hold the part relative to the plurality of conductive brushes, wherein the plurality of conductive brushes are mounted on the frame relative to the part.

[0059] 17. An insulation inspection method includes:

[0060] Connecting a lead to the part to be inspected;

[0061] At least one of the following: i) moving the part relative to the plurality of conductive brushes, and ii) moving the plurality of conductive brushes relative to the part;

[0062] When performing at least one of the following operations: i) moving the part relative to the plurality of conductive brushes and ii) moving the plurality of conductive brushes relative to the part, brushing the insulating material of the part with the plurality of conductive brushes;

[0063] Detecting at least one short circuit between one or more bristles of the plurality of conductive brushes and the exposed conductive element of the part through a plurality of voltage and current balance circuits, wherein the plurality of voltage and current balance circuits are connected to the plurality of conductive brushes; and

[0064] Detecting at least one defect in the insulating material of the part in response to the detected at least one short circuit.

[0065] 18. The insulation inspection method according to Solution 17 further includes:

[0066] Compiling the data collected through the plurality of voltage and current balance circuits and generating a report including the compiled data; and

[0067] Presenting the report.

[0068] 19. The insulation inspection method according to embodiment 18, wherein presenting the report includes: displaying the compiled data, generating an audible alarm, or transmitting the compiled data to a network device.

[0069] 20. The insulation inspection method according to embodiment 17, further comprising, after detecting a defect, removing at least one of the plurality of conductive brushes used to detect the defect from the part, so that the at least one of the plurality of conductive brushes is returned to a nominal voltage before using the at least one of the plurality of conductive brushes to detect another defect again.

[0070] Further applicable fields of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Description of the Drawings

[0071] The present disclosure will be more fully understood from the following detailed description and the drawings, wherein:

[0072] Figure 1 is a bottom view of a part of a stator, showing an example defect in an insulating coating;

[0073] Figure 2 is a schematic diagram of an example insulation inspection system for inspecting a stator according to the present disclosure and including a voltage and current balance circuit;

[0074] Figure 3 is a perspective view of an example part insulation inspection table according to the present disclosure, including a part rotating table and movable and fixed brushes;

[0075] Figure 4 is Figure 3 a side cross-sectional view of the part insulation inspection table of

[0076] Figure 5 is a cross-sectional view of an example "U" - shaped brush assembly according to the present disclosure, having three brushes (each having a set of bristles);

[0077] Figure 6 is a perspective partial exploded view of an example straight brush according to the present disclosure;

[0078] Figure 7 is a schematic diagram of an example insulation inspection system for testing a stator according to the present disclosure;

[0079] Figure 8 shows an example insulation inspection method for detecting, marking, identifying, and reporting defects according to the present disclosure;

[0080] Figure 9 shows an example defect indication program according to the present disclosure; and

[0081] Figure 10 is a functional block diagram of another part insulation inspection table including a movable brush and a fixed part support according to the present disclosure.

[0082] In the drawings, reference numerals may be reused to identify similar and / or identical elements. Detailed Description

[0083] During manufacturing, motors can be inspected to detect defects, such as defects in the insulation coating of stator electrical components. The insulation coating can be visually inspected. This can include a quality control technician visually inspecting for defects in the stator insulation coating using a magnifying glass. Such inspections are labor-intensive and are limited by the technician. A continuity tester can be used, which applies a voltage to the stator and detects when a short circuit exists. When there is a lack of insulating material at the point where the tester contacts the stator, current flows between the stator and the continuity tester.

[0084] The continuity tester can include a brush containing conductive bristles. The bristles can be moved through and brushed across various parts of the stator to detect the location of a short circuit (i.e., the defect location) where there is a lack of insulating material. The opposite can also occur, in which case the part (or stator) is moved through the bristles and the brush is fixed. A circuit is used to monitor changes in voltage at the brush. When a short circuit occurs, the voltage drops significantly. There are large fluctuations in voltage and current between when there is no short circuit and when there is a short circuit.

[0085] If not managed properly, large voltage and current fluctuations in the circuit can cause damage to components over time. Thus, the components degrade over time, and this degradation can have a negative impact on the operation of the circuit. For example, an A / D converter can have specific voltage and current limits for operation depending on the situation used. If any resulting drift occurs in circuit components (such as resistors or other circuit components), it can lead to voltage response behavior, resulting in voltage threshold setting problems and an inability to correctly detect short circuits. Degradation of circuit components can cause voltage drift, resulting in subsequent defects not being detected. Therefore, drift requires circuit adjustment and periodic recalibration, including adjustment of the threshold. A defect can be detected when the voltage drops below the threshold. As an example, the threshold can be set to 5 volts (V), which is significantly lower than the nominal and / or normal expected voltage (e.g., 24V). The threshold can be set to be less than or equal to 20% of the nominal voltage.

[0086] Drift can also lead to unsafe current levels. If circuit components degrade over time and a resulting change in the expected current in the circuit occurs, this can cause the current level in the circuit to exceed the threshold for perceived and / or actual bodily harm. Additionally, even if human exposure is mitigated, higher-than-expected current levels can cause damage to parts and brushes.

[0087] Examples described herein include an insulation inspection system that includes i) a part insulation inspection table having one or more continuity test brushes (referred to herein as brushes), and ii) one or more corresponding voltage and current balancing circuits, as Figure 2 and 7 shown. The brushes are mounted on the part insulation inspection table together with the part being inspected. The part is moved relative to one or more brushes, or the brushes are moved relative to the part, such that the bristles of one or more brushes contact the exposed conductive elements of the part at locations where insulation material is missing. The voltage and current balancing circuits provide a balanced voltage response at a nominal low current level, which currents are detected by the bristles of the continuity test brushes used to detect defects (or shorts). The voltage and current balancing provides stability, increases the life of circuit components, and provides improved functionality, allowing the insulation inspection system to be used in a variety of applications while ensuring human touch safety. In addition to the hardware described, the insulation inspection system also includes an algorithm for marking defective parts. The algorithm increases sensitivity for better defect detection.

[0088] Examples include an automated system having a rotating table for holding a stator and a table for holding a plurality of brushes for inspecting the side of the welded end and the crown end of the stator while the stator rotates. The stator is located on the rotating table, and the ears and / or surface of the stator are fixed to the rotating table by brackets, as described below. A plurality of different types of brushes are used to contact the sides of various parts of the stator, such as the three sides of the welded end. In one embodiment, this is done to ensure that the insulation material completely covers the weld and / or bare wire of the welded end or other parts being inspected. A plurality of brushes may be used to brush other parts of the stator, such as the wire insulation layer on the stator crown end. The brushes are designed such that the bristles of the brushes contact the entire crown area and detect the bare wire in the crown. The inspection may not include an inspection of the busbars of the stator. The brushes are designed to avoid a short circuit between the bristles and the stator core.

[0089] Each voltage and current balancing circuit increases the flexibility of safety by including a capacitor for voltage distribution and a pair of appropriately sized resistors. The amount of resistance of the pair of resistors is selected to produce a low current response. The capacitor and resistors are connected between the common terminal, the negative terminal, and the positive terminal of an analog-to-digital (A / D) converter. The value of the resistors is selected to produce a low current response throughout the operation of the voltage and current balancing circuit and / or at all operating points. The low current response makes the test setup safe for the operator. When there is no electrical short, the capacitor creates an open circuit condition. When a short is detected using a brush (e.g., a brush with carbon bristles), the voltage at the positive end of the corresponding capacitor drops, which causes the voltage across the corresponding resistor to drop somewhat, such that the voltage at each positive and negative terminal of the corresponding A / D converter remains within a predetermined voltage range (e.g., ±13V) relative to the voltage at the A / D common terminal.

[0090] The resistors should be selected such that the current flowing through the voltage and current balance circuit during a short circuit remains below a predetermined current (e.g., less than or equal to 25 mA, which cannot be perceptibly felt by human contact). From the perspective of the input analog voltage signal, when there is no short circuit, the positive terminal of the A / D converter will remain at the nominal operating voltage (e.g., 24 V) and the negative terminal of the A / D converter will remain at 0 V. When an insulation break occurs, i.e., the connection to the phase lead is shorted by the brush, the following changes occur in the corresponding voltage and current balance circuit. The corresponding positive A / D terminal is forced towards 0 V. It should be noted that due to the intermittent contact between the bristles, the positive A / D terminal may not reach 0 V completely, but in the case of a complete short circuit, the positive A / D terminal is forced to 0 V. A defect is detected when the positive A / D terminal drops to or below a predetermined threshold (e.g., 5 V) or is lower compared to the reference or no short circuit nominal voltage (e.g., 24 V).

[0091] Since the negative A / D terminal remains at 0 V, there is a 0 V difference between the positive and negative A / D terminals of the A / D converter, and thus the common A / D terminal is also at 0 V. Therefore, the resistors (hereinafter referred to as resistors R2, R4, R6... RM) connected between the negative A / D terminal and the common A / D terminal of the A / D converter experience a 0 V voltage drop (no current flow).

[0092] When a defect is detected, the corresponding capacitor will have available charge for discharging as needed, rather than directly connecting the power supply providing the nominal voltage to the short circuit (or defect). This allows each capacitor to maintain a constant voltage drop while minimizing the current flow in any branch of the voltage and current balance circuit, since the corresponding brush intermittently contacts the defect. This is achieved by keeping the resistor-capacitor (RC) time constant long enough so that the discharge of the capacitor does not cause large fluctuations in the voltage drop across the capacitor during the duration of the intermittent contact between the brush and the defect area. As an example, each time constant can be 24 seconds. This results in the resistors (hereinafter referred to as resistors R1, R3, R5... RN) connected between i) the capacitor and ii) the positive A / D terminal and the brush experiencing a voltage drop mainly during a short circuit condition.

[0093] To ensure that the current in the circuit does not exceed the current that can be perceived by the human body, resistors R1, R3, R5... RN are selected such that the current does not exceed a threshold (e.g., 1 milliampere (mA)) when there is a short circuit. This voltage and current balance operation at all operating points makes the entire voltage and current balance circuit safe for human touch and does not introduce current or voltage levels that would damage the bristles or the part being inspected. The current and voltage levels are kept below a predetermined threshold, e.g., to prevent the formation of an arc.

[0094] When there is a short circuit, the corresponding capacitor can discharge at an appropriate rate for fast and stable measurement. Current flows through the resistor and provides an analog voltage measurement for the corresponding A / D converter. Once the brush is removed from the defect and the short circuit no longer exists, the capacitor is charged until it returns to the open circuit state.

[0095] The voltage and current balance circuit prevents circuit components from deteriorating by preventing large fluctuations in voltage and current across the circuit components if a short circuit occurs. The values of the capacitor and resistor are selected to improve circuit performance and prevent circuit components from deteriorating due to parasitic voltage across the resistor. These values are selected to prevent drift in the circuit component values. This prevents the voltage drop from being greater than expected and the formation of an arc on the bristles of the brush.

[0096] A circuit design and defect detection analysis algorithm are disclosed to enable an automated system to detect notches and other defects in stator insulation. Multiple brushes are used to simultaneously inspect the welded ends and crown ends of the stator. The circuit accommodates multiple brushes and tracks the analog electrical responses of multiple voltage and current balance circuits. The voltage and current balance circuits allow the analog electrical responses to be tracked. Multichannel analog-to-digital conversion is performed while meeting electrical safety parameters. In addition, the defect detection analysis algorithm and the human-machine interface display are configured to allow simultaneous defect detection, identification, and notification, including marking defects for the end user.

[0097] Figure 1 A portion 100 of the stator is shown. The stator includes a pair of welded wires coated with an insulating material. Portion 100 includes a defect 102 where a portion of the insulating coating 104 is missing and the conductive material 106 of the wire is exposed. In Figure 1 shows the bottom (or welded end) of the stator. The stator includes a laminated stack (or body) 110 having a bottom surface 112 and a plurality of ear-like portions ( Figure 1 shows one ear-like portion 114). As an example, the insulating coating 104 can be epoxy resin.

[0098] Figure 2An insulation inspection system 200 for inspecting a stator 202 is shown. The insulation inspection system 200 includes a human-machine interface (HMI) 204 and a voltage and current balance circuit 206 that is connected to a power supply 208. The HMI 204 may include a control module 210, an A / D converter 212, a memory 214, a transceiver 216, a display 218, and an audio device 220. The display 218 includes LEDs 222 and / or other visual display and / or indicator elements. The control module 210 receives digital voltage data from the A / D converter 212, and the A / D converter 212 receives an analog input signal from the voltage and current balance circuit 206. The control module 210 detects a defect when the voltage of the analog output signal (or the corresponding digital signal) across the positive and negative terminals 223, 226 of the A / D converter 212 drops below a threshold (e.g., 5V or 20% of the nominal or normal expected voltage (e.g., 24V)). The normal expected voltage for no detected defect may be 24V. The control module 210 may indicate the detection of the defect through the display 218 and the audio device 220. The detection of the defect, the change (or drop) in voltage, the timing of the detection, and / or other relevant information may be stored in the memory 214. As an example, the detection of the defect may be stored together with the approximate location of the defect relative to one or more reference points on the stator 202.

[0099] The display 218 provides a visual aid for indicating the detection of a defect. This also provides an indication of when the defect was detected. When a defect is detected, the audio device 220 may provide a loud sound, such as a loud alarm signal. The audio device 220 may include, for example, a speaker. The control module 210 may report the detected defect and the corresponding information stored in the memory 214 to one or more network devices located away from the HMI 204 through the transceiver 216.

[0100] The voltage and current balance circuit 206 includes resistors R1, R2, and capacitor C. Resistor R1 has i) a first (or positive) terminal connected to the A / D converter 212 and the first end of the brush 228, and ii) a second end connected to the first end of the capacitor C and the positive terminal of the power supply 208. Resistor R2 includes i) a first end connected to the second (or negative) input terminal 226 of the A / D converter 212, the second end of the capacitor, one or more of the three-phase contacts 224, and the negative terminal of the power supply 208, and ii) a second end connected to the third (or common) terminal COM of the A / D converter 212. The common terminal COM is separate from either of the terminals 223, 226 and is not connected to either of the terminals 223, 226. The lead 225 is connected between i) the negative terminal 226, the first end of the resistor R2, and the second end of the capacitor C, and ii) one or more of the three-phase contacts 224. The first end of the capacitor C is connected to the positive terminal of the power supply 208. The second end of the capacitor C is connected to the negative terminal of the power supply 208.

[0101] Resistors R1, R2, and capacitor C are connected in series between the terminal 223 and the common terminal COM. In the example shown, the capacitor C is connected between the resistors R1 and R2. In an embodiment, the resistors R1 and R2 are directly connected to the terminals 223, 226 and directly connected to the capacitor C. Resistor R1 can be directly connected to the brush 228. Resistor R2 can be directly connected to the stator 202.

[0102] As an example, resistor R1 can be 20 - 30 kiloohms (kΩ), resistor R2 can be 400 - 500 kΩ, and the capacitor can be 500 - 1500 microfarads (μF). In one embodiment, R1 is 24 kΩ, R2 is 470 kΩ, and C is 1000 μF. The resistance of the resistors and the capacitance of the capacitor are selected to provide the RC time constant mentioned herein. In one embodiment, the resistances of the resistors R1, R2 are selected to limit the amount of current flowing through the stator 202, the voltage and current balance circuit 206, and the brush 228. The resistances of the resistors R1 and R2 and the capacitance of the capacitor C are selected to i) prevent arcing and sparking at the brush bristles 230 when a defect (short circuit) occurs, and ii) maintain an appropriate current balance in the circuit under all test conditions to be safe for human touch (less than 1 mA). For example, the resistances of the resistors R1 and R2 can be selected to prevent the current through the circuit 206, the brush 228, and the stator 202 from exceeding a predetermined threshold.

[0103] Select the resistance value to limit the current during all aspects of operation and balance the voltage load allowed across the channels of the A / D converter 212, such as the voltage loads associated with terminals 223, 226. In one embodiment, the current is maintained between 25 microamps (uA) and 1 mA whether there is a defect (a short circuit occurs) or no defect (no short circuit), due to i) the placement and selected values of resistors R1 and R2 and capacitor C in the voltage and current balancing circuit 206 relative to the power supply 208 (e.g., a 24 VDC power supply), and ii) the A / D voltage channel limits between different channels relative to the A / D common terminal COM. The resistance of R1 and R2 can be changed according to the A / D behavior limits to maintain the described current behavior. As an example, the channel limits can be such that the A / D channels of the A / D converter are within ±10 - 13 V of the A / D common terminal COM. In one embodiment, the channel limits are such that the A / D channels are within ±10.2 V of the A / D common terminal COM.

[0104] The capacitance rating of capacitor C is selected to provide a long enough RC time constant in conjunction with the value of R1 selected for current level reasons. This is done to provide a stable nominal voltage (e.g., a stable 24 V) to the voltage and current balancing circuit 208 during the time window required to determine if a short circuit has occurred. The R1*C value can provide a time constant of approximately 24 seconds. This provides a long enough time constant that does not need to be further increased with larger C values, but the time constant can be further increased. If the time constant is too small, the charging and discharging behavior of capacitor C will affect the circuit operation because when a defect occurs, the nominal voltage will no longer be maintained at a stable 24 V. This can make it challenging to assign a specific defect detection threshold because the voltage response will be intertwined with the behavior of capacitor C.

[0105] The capacitance of capacitor C affects the rate of change of the current flowing through stator 202, voltage and current balance circuit 206, and brush 228. Capacitor C is included as a protection device for brush 228 and bristles 230 and prevents current surges from the power supply 208 to the short - circuit location. When there is no short - circuit, capacitor C is charged. When there is a short - circuit, capacitor C discharges. Due to the RC time constant used, capacitor C does not discharge completely. This helps limit the current in the circuit during a short - circuit event. After discharging, the power supply 208 charges capacitor C. Typically, if the bristles are moving, the short - circuit lasts for a short time. Without capacitor C, resistors R1 and R2 may be damaged due to the short - circuit and the current surge through resistors R1 and R2. The capacitance value and resistance value can also be selected according to the application used to provide low current consumption for safe use by the operator. For example, the capacitance of capacitor C and the resistance of resistors R1, R2 can be selected to suit different brush head designs for defect detection. In one embodiment, the brush is designed to have a low impedance compared to the circuit components. The insulation inspection system 200 is capable of accommodating brushes with various different designs.

[0106] HMI 204 and / or A / D converter 212 detect the analog voltage across terminals 223, 226. The A / D signal is filtered by data sampling to eliminate the noise associated with the electrical behavior of the bristles of the brush. The voltage from the power supply 208 is provided across capacitor C, and capacitor C together with resistor R1 provides a stable voltage for brush 228, and one of the three - phase contacts 224 of stator 202 is connected to lead 225. When one or more conductive bristles 230 contact the exposed conductive elements of stator 202, current flows from one of the three - phase contacts 224 through stator 202 and to one or more bristles 230 in contact with the exposed conductive elements. The three - phase contacts 224 include three contacts; each phase of the three - phase stator 202 has one contact. In one embodiment, the three - phase contacts 224 are interconnected such that current can flow through any phase of stator 202. In another embodiment, voltage is provided to one of the three - phase contacts 224 of stator 202, and the brush is connected to lead 225.

[0107] The insulation inspection system 200 can be used to inspect the crown end 240, welded end 242, and / or other parts of stator 202 as shown. The insulation inspection system 200 can also be used to inspect individual electrical components and / or elements, one example of which is Figure 3 shown. The crown end 240 extends upward from the lamination stack 244. The welded end extends downward from the lamination stack 244. The bristles 230 can move along different parts of stator 202 to detect the locations where the insulating material is missing.

[0108] The insulation inspection system 200 includes software and hardware with an adjustable A / D voltage threshold for marking defects. As an example, the threshold for marking defects can be set to 5V, but it can vary for different applications. The control module 210 implements a detection algorithm that detects when the voltage across terminals 223, 226 drops below one of the A / D voltage thresholds and generates visual and / or audible signals to mark the detected defects.

[0109] The voltage and current balancing circuit described above can minimize the current levels at all operating points, whether or not a short circuit exists. The inclusion, selection, and arrangement of the resistors and capacitors as described above prevent large voltage and current fluctuations, thus preventing component degradation over time. This keeps the current levels below the thresholds associated with perceived and / or actual damage.

[0110] Figure 3 A parts insulation inspection station 300 is shown, which includes a parts rotating table assembly (which may be referred to as a parts support) 302, a frame 304 with rails 306, a brush holding member 308, a first "U" - shaped brush assembly 310, a first straight brush 312, a second straight brush 314, and a second "U" - shaped brush assembly (or "U" - shaped brush) 316. The brushes 310 and 312 together are referred to as the Gamma brush. Although Figure 3 - Figure 4 A bench setup for rotating the parts and holding the brushes in fixed positions is shown, but the bench can be modified to hold the parts in fixed positions and move the brushes relative to the parts. Figure 10 An example of this is shown in

[0111] Figure 3 The parts rotating table assembly 302 of includes a rotating table base / casing 320 and a support plate 322 that rotates relative to the base 320 (or the rotating table). The parts rotating table assembly 302 can include a parts support bracket 324. The support bracket 324 is fastened to the support plate 322 and the part 326 to be inspected (e.g., the stator of a motor). The support bracket 324 can be "C" - shaped and is fastened to the ear 328 of the stator lamination stack 329. If only one side is inspected at a time, the support bracket 324 can be replaced with a pin having a tapered end. If a pin is used, the stator needs to be flipped to test the other side. The part 326 rotates with the support plate 322.

[0112] The part rotating table assembly 302 is part of an automated system that includes a rotating table 320 with a support (or pallet) plate 322 on top. The pallet system can unload the parts (or stators) to be inspected from the rotating table 320 using at least one pallet, and the saddle can bring the pallet with the stator above the rotating table 320. The stator can also be transferred to a fixture located on the rotating table 320 (done by a robot or a person). The brushes of the system described below can be activated to move to a control position to be ready to contact a specific inspection part of the stator wires of the stator. The angular rotation of the stator is determined by the arrangement of one or more brushes to inspect the bare insulated wires of the stator. For example, using Figure 2 the system, a person or a robot can use one or more other brushes to inspect all the bare stator insulated wires.

[0113] The stator includes a crown end 330 and a welded end 332. The crown end 330 is inspected using a first "U" - shaped brush assembly 310 and straight brushes 312, 314. The first "U" - shaped brush assembly (or first "U" - shaped brush) 310 includes three brushes arranged in a "U" shape and is formed as part of a gamma brush. The gamma brush assembly also includes three brushes and the straight brush 312. A single brush member 334 holds the bristles 336 of the three brushes and the bristles 338 of the straight brush 312. The bristles 336 brush against the outer, upper, and inner sides of the crown end 330. The bristles 338 brush against the inner side of the crown end 330. The gamma brush assembly is capable of moving between an extended state and a retracted state, as shown by arrow 339. This can be achieved by, for example, using a handle 343 to loosen or tighten the clamp 340 of the swing arm 341. In one embodiment, the clamp 340 includes or is attached to a motor controlled by a control module (e.g., Figure 7 the control module). The brush holding member 308 can move laterally along corresponding tracks 306 as shown by arrows 342, 345 respectively. In an embodiment, the brush holding member 308 has slots that allow the brush holding member 308 to move closer to or further away from the stator to obtain proper contact with the stator. The brush 314 has bristles 344. The bristles 336, 338, and 344 can be held in grooves of the corresponding brush holding member (or brush holder) 308, and the brush holding member can have inner grooves for the ends of at least some of the bristles 336, 338, and 344.

[0114] The second "U" - shaped brush assembly 316 includes three brushes that are arranged in a "U" shape and are held by a single brush member 347. The three brushes of the second "U" - shaped brush assembly 316 brush against the inner, bottom, and outer sides of the welded end 332. Another "U" - shaped brush assembly is also included, as Figure 4 shown.

[0115] The stator has a bus bar 350 with three-phase contacts 352. The part (or stator) 326 to be inspected can be rotated so that the brushes of a single brush member 334 do not contact the bus bar 350. The part 326 can be rotated to inspect the stator crown not covered by the bus bar 350. This is a rotation greater than 180° and less than 360°. As shown, the single brush member 334 is in a 90° position relative to the part 326. With the above-described rotational movement of the part 326, the brushes 310, 312 can brush across the inner surface of the 360° crown end 330. The gamma brush assembly can be switched to a retracted state to allow the brush 314 to brush against the outer side of the 360° crown end 330. The part 326 is rotated 360° to perform this operation. The second "U" - shaped brush assembly 316 also brushes against the inner surface, bottom surface, and outer surface of the 360° welding end 332. While capturing data for the inner surface, bottom side surface, and outer surface of the welding end 332, the data collected for the outer surface of the crown end 330 can be captured.

[0116] Figure 4 A part insulation inspection table 300 is shown, which includes a part rotating table assembly 302, a frame 304 with tracks 306, a brush holding member 308, a first "U" - shaped brush assembly 310, a first straight brush 312, a second "U" - shaped brush assembly 316, and a third "U" - shaped brush assembly (or third "U" - shaped brush) 400. The first "U" - shaped brush assembly 310 includes bristles 336, and the bristles 336 include bristle groups 336A, 336B, 336C corresponding to the respective brushes.

[0117] The part rotating table assembly 302 includes a base 320 and a support plate 322. The support plate 322 is rotated by a motor 401 (as Figure 3 shown) through a shaft 402, and the motor 401 can be controlled by Figure 7 a control module. A support rod 404 extends through the shaft 402 and is connected to a support member 406, and the support member 406 is connected to and supports the "U" - shaped brush assemblies 316 and 400. The "U" - shaped brush assemblies 316 and 400 include "U" - shaped members 345, 408 and laterally extending members 410, 412, which are connected to the support member 406. The "U" - shaped brush assemblies 316 and 400 also include bristle groups 420A, 420B, 420C and 422A, 422B, 422C. The bristles of the bristle groups 420A, 420B, 420C and 422A, 422B, 422C may include bristles of different lengths.

[0118] In the example shown, the part 326 to be inspected is shown as the stator mentioned above, which has a crown end 330, a welding end 332, and a bus bar 350. The part 326 is held to the support plate 322 by a "C" - shaped support bracket 324.

[0119] Figure 5Shows a "U"-shaped brush assembly 500 with a holder design for three brushes 502, 504, 506, where the brushes 502, 504, 506 have respective bristle groups 508, 510, 512. The brushes 502, 504, 506 have respective wires 514, 516, 518 that are connected to respective voltage and current balancing circuits, Figure 7 and an example of these circuits is shown. The bristles of the bristle groups 508, 510, 512 are conductive and flexible and are held by crimps and / or bristle retaining members 520, 522, 524. The brushes 502, 504, 506 have interlocking grooves that enable them to be held together and attached to a laterally extending member, similar to Figure 3 some of the brushes shown in

[0120] The holder design (or holder) can be adapted to different stator models, different stator sizes of the same series, etc. The holder includes a plate 521 attached to the brush body, where the brush body has a first respective channel for the wires 514, 516, 518 and a second respective channel for mounting the bristle retaining members 520, 522, 524. The holder can be "U"-shaped, flat, or have other shapes to accommodate the detection area of the stator's bare wires. The wires 514, 516, 518 are used to monitor the voltage at the brushes 502, 504, 506 respectively in order to determine the location of a defect (or the location where a short circuit is detected).

[0121] The bristles (or fibers) of the brushes 502, 504, 506 can be carbon fibers, the ends of which are embedded in epoxy resin to prevent the carbon fibers from "falling out" and / or breaking from the bristle retaining members 520, 522, 524. The epoxy resin can be conductive and can include additives to increase the viscosity of the epoxy resin and / or increase the electrical conductivity of the epoxy resin and prevent wicking (or the movement of the epoxy resin along the fibers). Other additives can be zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), or three-dimensional (3D) nanomaterials and depend on the shape and size of the additives. Both nanometer-sized particles and micron-sized particles can be included, such as metal, non-metal, polymer, and non-polymer particles. Other additives can include carbon-based nanomaterials and particles, such as graphene, graphene nanosheets, graphite, fullerenes, carbon nanotubes, carbon black, and carbon dots. The epoxy resin can increase the hardness of the bristles. Figure 6 An example structural arrangement of a brush is shown, which can be used for each of the brushes 502, 504, 506.

[0122] Figure 6Shows a straight brush 600 and corresponding bristles 602, a conductive crimp layer 604, an epoxy resin layer 606, and a conductive strip 608. The epoxy resin layer 606 is outlined and shown in a transparent form to show the conductive crimp layer 604. The bristles 602 include a first end 610 and a second end 612. The first end 610 is not coated and / or embedded in the epoxy resin. The second end 612 is coated and embedded in the epoxy resin of the epoxy resin layer 606. The second end 612 is coated in the epoxy resin. The epoxy resin can be conductive and connect the second end 612, the conductive crimp layer 604, and the conductive strip 608. The conductive crimp layer 604 wraps around at least three sides of the second end 612, crimps onto the bristles 602, and holds the bristles 602 together. In one embodiment, the conductive crimp layer 604 wraps around four sides of the second end 612. Although Figure 6 not shown in, the conductive strip 608 folds over the second end 612 and covers at least one side of the conductive crimp layer 604. The conductive strip 608 covers three sides of the second end 612. The conductive strip 608 is connected to a wire 614, which can be an output wire for detecting a short circuit.

[0123] The bristles 602 can include carbon fiber, metal fiber, or other conductive fibers. The density, stiffness, and draw strength characteristics of the bristles can be selected and optimized. The conductive crimp layer 604 and the conductive strip 608 can be formed of a metal material. In one embodiment, the second end 612, the conductive crimp layer 604, the epoxy resin layer 606, and the conductive strip 608 are placed, set, and cured within a brush holder. An example brush holder is as Figure 5 shown.

[0124] Figure 7 Shows an insulation inspection system 700 for testing a stator 702. The insulation inspection system 700 is similar to the Figure 2 insulation inspection system, but includes a component insulation inspection assembly 704, such as the Figure 3 - Figure 4 component insulation inspection table 300, and a plurality of voltage and current balance circuits 706 for a plurality of brushes 708 of the component insulation inspection assembly 704, respectively.

[0125] The insulation inspection system 700 includes an HMI 710. The HMI 710 includes a control module 711, an A / D converter 712 for the voltage and current balance circuit 706 respectively, a memory 714, a transceiver 716, a display 718, and an audio device 720. The display 718 includes an LED 722 and / or other visual display and / or indicating elements. The control module 711 receives digital voltage data from the A / D converter 712, and the A / D converter 712 receives an analog input signal from the voltage and current balance circuit 706. When the voltage of the analog output signal (or the corresponding digital signal) drops below a threshold (e.g., 5V or 20% of the nominal or normal expected voltage (e.g., 24V)), the control module 711 detects a defect. The control module 711 can indicate the detection of the defect through the display 718 and the audio device 720. The detection of the defect, the change (or drop) of the voltage, the timing of the detection, and / or other relevant information can be stored in the memory 714, as described above and further described below.

[0126] The part insulation inspection assembly 704 includes a motor 730 and a brush 732, and may also include a sensor 734. The motor 730 may include a motor for rotating a support plate for a part (such as the stator 702). The motor 730 may also include i) a motor for moving the brush along a track and / or relative to various parts of the part to be inspected, and / or ii) a motor for moving the brush between a deployed position and a retracted position. The brush 732 may include a straight brush, a "U" - shaped brush, and / or other brushes. Some brushes may be implemented in a gamma brush assembly. The sensor 734 may include a motor encoder for determining the position of the shaft of the motor 730, a camera for monitoring the position of the brush 732 relative to the part to be inspected, a speed sensor for monitoring the speed of one or more motors 730, and / or other sensors.

[0127] The stator 702 includes a crown end 740, a lamination stack 742, and a welded end 744. The crown end 740 extends from the top surface 746 of the lamination stack 742. The welded end 744 extends from the bottom surface 748 of the lamination stack 742. The stator 702 has three phases with respective three - phase contacts 750.

[0128] Each of the voltage and current balance circuits 706 includes i) a pair of resistors R1 and R2, R3 and R4, …… or RM and RN, and ii) a respective one of the capacitors C1 - CP, where M, N, and P are integers. The number of resistor pairs is equal to the number of capacitors.

[0129] Each of the resistors R1, R3, …, RM has i) a first end connected to the first (or positive) terminal of a respective one of the A / D converters 712 and a respective one of the brushes 732, and ii) a second end connected to a respective one of the capacitors C1-CP and the positive terminal of the power supply 760. The first ends of the capacitors C1-CP are connected to the resistors R1, R3, …, RM and to the positive terminal of the power supply 760. The second ends of the capacitors C1-CP are connected to the negative terminal of the power supply 760, a respective one of the resistors R2, R4, …, RN, the second (or negative) terminal of a respective one of the A / D converters 712, and one or more of the three-phase contacts 750.

[0130] Each of the resistors R2, R4, …, RN includes i) a first end connected to the third (or common) terminal of a respective one of the A / D converters 712, and ii) a second end connected to a respective one of the capacitors C1-CP, the negative terminal of the power supply 760, and one or more of the three-phase contacts 750 of the stator 702. The lead 725 is connected between i) the negative terminals of the A / D converters 712, the second ends of the resistors R2, R4, …, RN, and the second ends of the capacitors C1-CP and ii) one or more of the three-phase contacts 750.

[0131] The resistors and capacitors of each voltage and current balancing circuit �06 are connected in series between the positive terminal and the common terminal of the A / D converter 712. In the example shown, each capacitor C1-CP is connected between a respective one of the resistors R1, R3, …, RM and a respective one of the resistors R2, R4, …, RN. In an embodiment, the resistors R1, R3, …, RM and R2, R4, …, RN are directly connected to respective ones of the terminals of the A / D converter 712 and directly connected to respective ones of the capacitors C1-CP. The resistors R2, R4, …, RN may be directly connected to the stator 702. The resistors R1, R3, …, RM may be directly connected to the brushes 732.

[0132] As an example, the resistors R1, R3, …, RM may each be 20-30 kiloohms (kΩ), the resistors R2, R4, …, RN may each be 400-500 kΩ, and the capacitors may each be 500-1500 microfarads (μF). In an embodiment, the resistors R1, R3, …, RM are each 24 kΩ, the resistors R2, R4, …, RN are each 470 kΩ, and the capacitors C1-CP are each 1000 μF.

[0133] The resistances of resistors R1, R3, …, RM, R2, R4, …, RN and the capacitances of capacitors C1 - CP are selected to provide the RC time constants mentioned herein. In an embodiment, the resistances are selected to limit the amount of current flowing through stator 702, voltage and current balance circuit 706, and brushes 1 - N. The resistances and capacitances are selected to i) prevent the formation of arcs and sparks at the bristles of brushes 1 - N in the event of a defect (short circuit), and ii) maintain proper current balance in the circuit during all test conditions to maintain safety against human touch (less than 1 mA). For example, the resistances can be selected to prevent the current through circuit 700, brushes 1 - N, and stator 702 from exceeding a predetermined threshold.

[0134] The resistance values are selected to limit the current during all aspects of operation and balance the voltage loads allowed across the channels of A / D converter 712, such as the voltage loads associated with the positive and negative terminals of A / D converter 712. In one embodiment, the current remains between 25 microamps (μA) and 1 mA whether there is a defect (short circuit occurs) or no defect (no short circuit), due to i) the placement and selected values of the resistors and capacitors in voltage and current balance circuit 706 relative to power supply 760 (e.g., a 24 VDC power supply), and ii) the A / D voltage channel limits between different channels relative to the A / D common terminal COM. The resistance can be changed according to the A / D behavior limits to maintain the described current behavior. As an example, the channel limits can be such that the A / D channels of A / D converter 712 are within ±10 - 13 V of the A / D common terminal COM. In one embodiment, the channel limit is such that the A / D channels are within ±10.2 V of the A / D common terminal COM.

[0135] The capacitance ratings of the capacitors are selected to, together with the resistances of resistors R1, R3, …, RM selected for current level reasons, provide a sufficiently long RC time constant. This is done to provide a stable nominal voltage (e.g., a stable 24 V) to voltage and current balance circuit 706 during the time window required to determine if a short circuit has occurred. The RC value can provide a time constant of approximately 24 seconds. This provides a sufficiently long time constant that does not need to be further increased with larger C values, but the time constant can be further increased. If the time constant is too small, the charging and discharging behavior of capacitors C1 - CP will affect the circuit operation because when a defect occurs, the nominal voltage will no longer be maintained at a stable 24 V. This can make it challenging to assign a specific defect detection threshold because the voltage response will be intertwined with the behavior of capacitors C1 - CP.

[0136] In one embodiment, the resistances of resistors R1, R3, …, RM and R2, R4, …, RN are selected to limit the amount of current flowing through the stator 702, the voltage and current balance circuit 706, and the brush 732. The resistances of resistors R1, R3, …, RM and R2, R4, …, RN and the capacitances of capacitors C1 - CP are selected to prevent arcing and sparking at the bristles of the brush 732 in the event of a defect (short circuit). For example, the resistances of resistors R1, R3, …, RM and R2, R4, …, RN can be selected to prevent the current through each brush 732 from exceeding a predetermined threshold.

[0137] The voltage and current balance circuit 706 operates Figure 2 similarly to the voltage and current balance circuit 206 of Figure 3 - Figure 4 The brush 732 can include the brushes 310, 312, 314, 316, 400 of

[0138] Figure 8 An example insulation inspection method is shown for detecting, marking, identifying, and reporting defects through a plurality of brushes (e.g., Figure 3 - Figure 4 and the brushes in 7). The insulation inspection method implements a defect detection analysis algorithm, including the following operations. These operations can be performed repeatedly. The operations shown in solid boxes can be performed by Figure 2 the insulation inspection system 200 of Figure 7 and / or the insulation inspection system 700 of Figure 3 - Figure 4 using the part insulation inspection table 300 of Figure 7 or another table similar to the part insulation inspection table 300. Although these operations are mainly described with respect to

[0139]

[0140] At 800, the lead 725 is connected to the part to be inspected, such as the stator 702 or other electrical components. For example, the lead 725 can be connected to one or more of the three - phase contacts 750.At 802, the control module 711 begins to rotate the part according to the movement profile while moving the brush across the insulated portion of the part. The part can be rotated in an incremental or continuous motion manner. The part can be rotated while performing the following operations. The brush 732 is moved across the insulated portion of the part being inspected. This includes brushing the bristles of the brush 732 across the insulated portion such that one or more bristles contact any uninsulated (exposed) conductive material of the part. The exposed conductive material is at the voltage applied to the part by the power supply 760. When one or more bristles contact the exposed portion of the part, a short circuit occurs and the control module 711 detects a voltage drop. The short circuit results in a sharp voltage drop from the nominal (or normally expected) level below a threshold level. The bristles maintain contact with the part while moving relative to the part.

[0141] At 804A, 804B, ..., 804P (collectively operation 804), the control module 210 begins to monitor the voltage at the input terminal of the A / D converter 712, thus monitoring the voltage at the bristles of the brush 732. This can include determining the position of the bristles of the brush 732 relative to one or more reference points of the part being inspected. In one embodiment, the bristles of the brush 732 initially contact a corresponding position on the part whose coordinates are known to the control module, and then the brush 732 is moved. As an example, the movement including position and speed information can be tracked by the control module 711 based on the output of the sensor 734.

[0142] At 806A, 806B, ..., 806P (collectively operation 806), the control module 811 determines whether a defect has been detected. If one or more defects have been detected, operations 808A, 808B, ..., 808P (collectively operation 808) are performed for the brush for which the defect was detected, otherwise operations 812A, 812B, ..., 81B can be performed for the brush for which no defect was detected. A defect is detected when there is a short circuit between one or more bristles of one or more brushes 732 and one or more exposed conductive elements of the part. When the part is a stator, there may be a short circuit between one or more bristles and one or more exposed wires of the stator, and thus there may be a short circuit between one or more bristles and one or more three-phase contacts 750 of the stator 702.

[0143] At 808A, 808B, ..., 808P (collectively operation 808), the control module executes a defect indication program, as Figure 9 shown.

[0144] At 900, the control module indicates detected defects visually and / or auditorily via one or more indicators (e.g., via display 718, LED 722, and / or audio device 720). In one embodiment, a message is displayed via display 718. The message may include information about the detected defect, including the location of the defect, the time the defect was detected, the voltage drop at A / D converter 712 experienced due to the defect, the rate of voltage drop, how long the defect was detected, and so on. In another embodiment, the message is sent from HMI 710 to another network device via transceiver 716. Defects can be detected in a short time depending on the size of the defect and the moving speed of the corresponding brush relative to the part being inspected. The location of the defect can be indicated relative to one or more reference points on the part being inspected.

[0145] As an example, a ring can be attached to the welding end 744 and have a clock index and / or the stack of laminations 742 can have a reference point. The index and / or reference point can be used to determine the location of the detected defect. In one embodiment, the control module 711 marks the defect by lighting a red LED (one for each defect) or displaying a red icon (one for each defect). For brushes where no defect is detected, a green LED can be turned on and / or a green icon can be displayed. The display can include an LED and / or display icon for each brush, indicating whether a defect has been detected using that brush. In another embodiment, the control module 711 marks the defect by initiating an audible defect alarm signal.

[0146] At 902, the control module 711 records information about the detected defect. At 904, the brush 732 is removed from the part (i.e., moved to a storage location away from the part). At 906, the voltage of the voltage and current balancing circuit 706 returns to the nominal level.

[0147] At 908, the control module 711 stops indicating that a defect has been detected and returns one or more indicators to the normal state. For example, the audio device 720 that can provide an audible message (or alarm) is turned off. The glowing LED turns green or is turned off. The displayed icon indicating the presence of a defect changes from red to green or is no longer displayed. Figure 8 Operations 810A, 810B,..., 810P (collectively referred to as operations 810) can be performed after operation 908.

[0148] At 810, the control module 711 can determine whether there are more parts to be inspected. If so, operation 804 can be performed; otherwise, the method can end.

[0149] In step 812, the control module 711 may compile defect information for each detected defect, including the location of the defect and other relevant information. The compiled information may be stored as a compiled information file in the memory 714.

[0150] At 814, the control module 711 may report the overall compiled defect presence report and / or the compiled information in part thereof via the display 718 and / or the audio device 720. The report and / or the compiled information may be transmitted to a remote network device via the transceiver 716. The information may include the location of the defect, one or more defect areas in which the defect is identified, and / or other relevant information (e.g., any of the above information). This may include an indication of the defect location on the part, the time when the defect was detected, and / or other information indicating the defect location.

[0151] Based on the detected defects and the corresponding information, the defects can then be inspected and repaired. The control module 711 may rotate the part to manually inspect and / or repair the defect. If the defect cannot be repaired and / or if there are too many defects, the part may be recycled or discarded. The control module 711 may indicate whether the part can be repaired and / or whether the part should be recycled or discarded based on the information collected.

[0152] Figure 10 A part insulation inspection table 1000 is shown, which includes a moving brush 1002 and a fixed part support 1004 that holds the part 1006 in a fixed position. Any number of brushes may be included. The brush may be any of the above types. Figure 10 is provided as an example and shows an example arrangement of the brush relative to the part. The brush may adopt various other arrangements relative to the part. The part 1006 may be a stator or other type of part. The brush 1002 may be held by a brush holder 1008, which may be mounted to one or more support members. An example support member 1010 is shown. One or more motors may be included to move one or more support members, thereby moving the brush 1002. The motor may be mounted on the frame 1011. A motor 1012 is shown in the figure, which moves the support member 1010. The motor moves the brush 1002 relative to the part. The movement may be a rotational movement or a linear movement. A motor may be included to move the brush between a deployed state and a retracted state. The brush 1002 may be connected to the voltage and current balance circuit of the insulation inspection system, as Figure 7 shown. The part support 1004 may also be mounted to the frame 1011.

[0153] The exemplary automated system disclosed herein detects nicks in the bare wires at the welded ends and crown ends of the assembled stator. The brush holder is adjustable to handle different stator sizes of the same series as well as different brush head types and designs. This provides a high degree of flexibility in meeting the requirements of a given application. The automated system can be configured with a fixed brush and rotate the stator relative to the brush, or can be configured with a fixed stator support member and rotate (or move) the brush relative to the stator. The brush is configured to detect the bare wires at the welded ends and crown ends. The brush holder is optimized for each specific stator size and design. In one embodiment, the ends of carbon fibers are embedded in epoxy resin and inserted into the grooves of the brush holder. Additives (such as carbon black) can be used to increase the viscosity of the epoxy resin to prevent the bristles from pulling out, provide low and consistent interfacial resistance, and prevent wicking. The bristle length of the "U" - shaped conductive brush is selected according to each application purpose to avoid significant overlap of the bristles i) at the curved (or 90° angle) portion of the "U" - shaped holder to allow proper deflection of the bristles, and ii) at the contact portion (or contact end) where the bristles contact the part being inspected.

[0154] The above - mentioned example includes a circuit design for multi - channel analog - to - digital conversion of brush signals while meeting the electrical safety parameters for the operator. This circuit design allows concurrent analog signal tracking for each brush integrated in the automated system. The multi - channel circuit design can include multiple brushes to comprehensively inspect each insulated portion of the part (perform electrical tests on each insulated portion of the part).

[0155] An analysis algorithm is provided that independently monitors the digitally converted signals from each brush while tracking the movement profiles of the brush or the part being inspected as the brush and the part move relative to each other (e.g., rotate), for both defect identification and position determination. The HMI display is used for simultaneous defect detection and notification (e.g., marking). In one embodiment, when inspections are performed using a repeatable movement profile, the location of the detected defects is reported to the end - user and / or a remote network device.

[0156] The inspection circuit and analysis algorithm disclosed herein enable the automated system to inspect for cuts, nicks, and other defects in the wire insulation layers at both ends of the stator assembly. The inspection circuit has improved circuit performance to avoid degradation of circuit components due to parasitic voltages across the inspection circuit resistance. The analysis algorithm is used to independently monitor the digitally converted signals from each brush while tracking the movement profiles of the brush and / or the part being inspected as they move relative to each other, for both defect identification and approximate location. The HMI display is updated for the end - user to allow simultaneous brush detection and notification for marking defects. The HMI display can be used as a visual aid to understand the time and location of defect occurrence. If there is a short - circuit, the corresponding defect can be shown via the HMI on the screen and / or using an audible alarm.

[0157] By adding capacitors at each analog-to-digital channel to distribute voltage within the circuit, the flexibility of safety can be improved. Resistors with selected resistances are included to generate a low-current response, making the test setup safe for the operator and preventing arcing between the bristles of the brush and the part being inspected. When there is no short circuit (short-circuit condition), the capacitor creates an open-circuit condition. When a short circuit (or short-circuit condition) is detected through the brush, the voltage at the positive terminal of the corresponding capacitor drops, which causes a drop in the voltage across the two ends of the corresponding resistor pair, such that the voltage of each positive and negative terminal of the corresponding A / D converter remains within a predetermined voltage range (e.g., ±13V) relative to the voltage on the A / D common terminal. Once the brush is moved away from the short-circuit position, the capacitor is charged until it returns to its open-circuit state. The voltage drop and the amount of current flowing through the circuit due to the short circuit are limited. This helps prevent the circuit from deteriorating and makes the circuit safe for human contact. The capacitor and resistor values are set to meet the application requirements while providing low current consumption for safe use by the operator.

[0158] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in many forms. Thus, although the disclosure includes specific examples, the true scope of the disclosure should not be so limited since other modifications will become apparent after studying the drawings, the specification, and the appended claims. It should be understood that one or more steps within a method can be performed in a different order (or simultaneously) without changing the principles of the disclosure. Additionally, although each embodiment above is described as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more of the embodiments with each other are still within the scope of the disclosure.

[0159] A variety of terms, including "connect", "join", "couple", "adjacent", "next to", "on", "above", "below", and "disposed", are used to describe the spatial and functional relationships between various elements (e.g., between modules, circuit elements, semiconductor layers, etc.). Unless explicitly described as "direct", when describing the relationship between a first element and a second element in the above disclosure, the relationship can be a direct relationship where no other intermediate element exists between the first element and the second element, but can also be an indirect relationship where one or more intermediate elements (spatially or functionally) exist between the first element and the second element. As used herein, the phrase "at least one of A, B, and C" should be interpreted to mean a logical "or" using non-exclusive logic (A or B or C), and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C".

[0160] In the drawings, the direction indicated by an arrow (as shown by the arrow) generally indicates the information flow (such as data or instructions) of interest in the illustration. For example, when element A and element B exchange various information, but the information sent from element A to element B is relevant to the illustration, the arrow can point from element A to element B. This one-way arrow does not mean that no other information is sent from element B to element A. Additionally, for the information sent from element A to element B, element B can send a request for the information or an acknowledgment of the receipt of the information to element A.

[0161] In the present application including the following definitions, the term "module" or the term "controller" can be replaced by the term "circuit". The term "module" can refer to the following, be a part of the following, or include the following: application specific integrated circuit (ASIC); digital, analog, or analog / digital hybrid discrete circuit; digital, analog, or analog / digital hybrid integrated circuit; combinational logic circuit; field programmable gate array (FPGA); processor circuit (shared, dedicated, or group) that executes code; memory circuit (shared, dedicated, or group) that stores the code executed by the processor circuit; other suitable hardware components that provide the function; or a combination of some or all of the above, such as in a system on a chip.

[0162] A module can include one or more interface circuits. In some examples, the interface circuit can include a wired or wireless interface connected to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functions of any given module of the present disclosure can be distributed among multiple modules connected via the interface circuit. For example, multiple modules can allow load balancing. In another example, a server (also referred to as remote or cloud) module can perform certain functions on behalf of a client module.

[0163] As used above, the term "code" can include software, firmware, and / or microcode, and can refer to programs, routines, functions, classes, data structures, and / or objects. The term "shared processor circuit" encompasses a single processor circuit that executes some or all of the code in multiple modules. The term "group of processor circuits" encompasses a processor circuit that, in combination with other processor circuits, executes some or all of the code from one or more modules. References to multiple processor circuits include multiple processor circuits on separate dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or combinations of the above. The term "shared memory circuit" encompasses a single memory circuit that stores some or all of the code from multiple modules. The term "group of memory circuits" encompasses a memory circuit that, in combination with other memories, stores some or all of the code from one or more modules.

[0164] The term "memory circuit" is a subset of the term "computer-readable medium". As used herein, the term "computer-readable medium" does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); thus, the term "computer-readable medium" can be considered tangible and non-transitory. Non-limiting examples of non-transitory tangible computer-readable media are non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital tapes or hard disk drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs).

[0165] The devices and methods described in this application can be partially or fully implemented by a special-purpose computer created by configuring a general-purpose computer to execute one or more specific functions implemented in a computer program. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be converted into computer programs through the routine work of a technician or programmer.

[0166] A computer program includes processor-executable instructions that are stored on at least one non-transitory tangible computer-readable medium. The computer program can also include or rely on the stored data. The computer program can include a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0167] These computer programs can include: (i) descriptive text to be parsed, such as HTML (HyperText Markup Language), XML (eXtensible Markup Language), or JSON (JavaScript Object Notation), (ii) compiled code, (iii) object code generated by a compiler from source code, (iv) source code executed by an interpreter, (v) source code compiled and executed by a just-in-time compiler, etc. By way of example only, the source code can be written using the syntax of a language including the following languages: C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Fortran, Perl, Pascal, Curl, OCaml, HTML5 (HyperText Markup Language version 5), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK and

Claims

1. An insulation inspection system, comprising: a plurality of conductive brushes arranged to brush over an insulated portion of a part to be inspected; a plurality of voltage and current balancing circuits connected to the plurality of conductive brushes, wherein each of the plurality of voltage and current balancing circuits is configured to detect a short circuit between one or more bristles of the plurality of conductive brushes and an exposed conductive element of the part; and a control module configured to detect a defect in the insulating material of the part in response to the detected short circuit.

2. The insulation inspection system according to claim 1, further comprising a plurality of analog-to-digital converters configured to receive the analog signal outputs of the plurality of voltage and current balancing circuits.

3. The insulation inspection system according to claim 2, wherein the control module is configured to i) simultaneously monitor the digital outputs of the plurality of analog-to-digital converters, and ii) simultaneously determine whether there is a defect at the part location of each of the plurality of conductive brushes.

4. The insulation inspection system according to claim 1, wherein the control module is configured to i) track the position of each of the plurality of conductive brushes relative to the part when the part moves relative to the plurality of conductive brushes, and ii) determine the location of the detected defect based on the tracked position of the corresponding one of the plurality of conductive brushes relative to the part.

5. The insulation inspection system according to claim 1, wherein the control module is configured to i) track the position of each of the plurality of conductive brushes relative to the part when the plurality of conductive brushes move relative to the part, and ii) determine the location of the detected defect based on the tracked position of the corresponding one of the plurality of conductive brushes relative to the part.

6. The insulation inspection system according to claim 1, further comprising a display, Among them, the control module being configured to indicate the detected defect on the display.

7. The insulation inspection system according to claim 1, further comprising an audio device, Among them, the control module being configured to indicate the detected defect through the audio device.

8. The insulation inspection system according to claim 1, wherein, Each of the plurality of voltage and current balancing circuits includes a pair of resistors and a capacitor.

9. The insulation inspection system according to claim 1, further comprising a plurality of analog-to-digital converters, wherein: each of the plurality of analog-to-digital converters includes a set of input terminals; and each of the plurality of voltage and current balancing circuits includes a pair of resistors and a respective capacitor, the pair of resistors and the respective capacitor being connected in series between two terminals of the set of input terminals of the corresponding one of the plurality of analog-to-digital converters.

10. The insulation inspection system according to claim 9, wherein: the pair of resistors of each of the plurality of voltage and current balancing circuits includes a first resistor and a second resistor; the set of input terminals of each of the plurality of analog-to-digital converters includes a positive terminal, a negative terminal, and a common terminal; the first resistor of each pair of resistors includes i) a first end connected to the corresponding one of the positive terminals and connected to the corresponding one of the plurality of conductive brushes, and ii) a second end connected to the first end of the respective capacitor; The second resistor includes i) a first end connected to a respective one of the common terminals, and ii) a second end connected to the respective capacitor and to the second end of the part.

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