Defect inspection device for winding

Abstract

Provided is a defect inspection device for a winding (1) that is caused to travel with a certain tension applied so as to be wound around a winding-receiving member, said defect inspection device comprising: a power supply (6) that applies a voltage between the winding (1) and a sensor (5) which is disposed in a travel path for the winding (1) leading to the winding-receiving member; and a programmable resistor (12) that is connected between the sensor (5) and the power supply (6), wherein, while the presence or absence of a defect is determined by a defect presence / absence inspection unit (3), a resistance value of the programmable resistor (12) is increased when discharge current generated between the sensor (5) and the winding (1) exceeds a predetermined threshold value for the initiation of protection, and burning of the winding (1) is prevented.

Description

Winding defect inspection equipment

[0001] The present disclosure relates to a defect inspection device for a winding.

[0002] If there are defects such as scratches or pinholes in the insulating layer of the windings of a rotating electric machine, the insulation between the winding and the winding core or between the winding and ground will be reduced. This can cause insulation breakdown between adjacent windings of the coils that make up the winding, which can lead to problems such as reduced performance, burnout, or electrical leakage in the rotating electric machine. For this reason, rotating electric machines require inspection of their windings for defects.

[0003] Defects in the windings can be detected by applying a voltage to the windings while the train is running and detecting the discharge current that occurs in the defective part of the winding. However, if the discharge current is not limited, the insulation layer of the windings may be destroyed, causing the defect to expand further. Therefore, it is necessary to prevent the insulation layer from being destroyed when inspecting for winding defects.

[0004] Conventional winding defect inspection technology involves inserting a fixed resistor between the inspection power supply and the winding to inspect for large flaws caused by friction between the winding and the nozzle that guides the winding. A winding defect detection device is known that uses this resistor to limit the current that flows during inspection, thereby preventing the winding from burning out (see, for example, Patent Document 1).

[0005] Patent No. 6408229

[0006] According to the technology disclosed in Patent Document 1, a fixed resistor is inserted between the inspection power supply and the winding to limit the current flowing to large flaws (1 mm) caused by friction between the winding and the nozzle that guides the winding to the wound member. This prevents burnout at the flawed area of ​​the winding and enables the winding to be inspected for flaws. However, when inspecting for defects in the winding, such as pinholes or dents in a thin insulating layer, the required power supply voltage and discharge current vary depending on the size of the defect.

[0007] Therefore, when using a fixed resistor to inspect for large and small pinhole diameter defects or weak defects such as dents in the insulation layer, applying a low voltage can detect large defects but not small and weak defects. On the other hand, applying a high voltage can detect small and weak defects, but when detecting large defects, there is a risk of damaging the insulation layer of the winding around the large defects. Thus, there is a problem in that fixed resistors cannot simultaneously detect all types of defects and prevent damage to the insulation layer of the winding.

[0008] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a winding defect inspection device that can reliably inspect windings for defects and flaws while the train is running, and that prevents damage to the winding insulation layer.

[0009] The winding defect inspection device disclosed herein inspects for defects in a winding that is run under a constant tension in order to be wound around a wound member, and includes a sensor arranged in the running path of the winding to the wound member, a power supply that applies a voltage between the sensor and the winding, a first programmable resistor connected between the sensor and the power supply, first discharge current detection means that detects a first discharge current that occurs between the sensor and the winding by applying a voltage, a first defect inspection unit that determines whether or not there is a defect in the winding based on the result of comparing the first discharge current with a predetermined defect presence / absence threshold, and a condition setting unit that, while determining whether or not there is a defect using the first defect inspection unit, instructs the first programmable resistor to increase its resistance value if the first discharge current exceeds a predetermined protection start threshold.

[0010] The winding defect inspection device disclosed herein can detect large defects in windings while the train is running, while preventing damage to the insulating layer of the winding, and can also reliably detect small defects and scratches at the same time as large defects.

[0011] FIG. 1 is a block diagram showing the configuration of a winding defect inspection apparatus according to a first embodiment. FIG. 2 is a diagram explaining discharge between a winding and a sensor. FIG. 3 is a diagram showing the relationship between a discharge current and a breakdown threshold. FIG. 4 is a flowchart explaining the operation of the winding defect inspection apparatus according to the first embodiment. FIG. 5 is a diagram explaining a discharge current, a post-processing inspection signal, and a defect presence / absence signal detected by the winding defect inspection apparatus according to the first embodiment. FIG. 6 is a diagram showing an example of the circuit configuration of a defect presence / absence inspection unit of the winding defect inspection apparatus according to the first embodiment. FIG. 7 is a diagram explaining an example of the hardware configuration of a condition setting unit of the winding defect inspection apparatus according to the first embodiment. FIG. 8 is a diagram showing an example of the circuit configuration of a voltage dividing means of the winding defect inspection apparatus according to the first embodiment. FIG. 9 is a flowchart explaining the operation of the winding defect inspection apparatus according to the first embodiment. FIG. 10 is a diagram explaining stepwise increasing the resistance value of a programmable resistor of the winding defect inspection apparatus according to the first embodiment. FIG. 11 is a block diagram showing the configuration of a winding defect inspection apparatus according to a third embodiment. FIG. 12 is a flowchart explaining the operation of the winding defect inspection apparatus according to the third embodiment. FIG. 13 is a diagram explaining a discharge current, a post-processing inspection signal, and a defect presence / absence signal detected by the winding defect inspection apparatus according to the third embodiment. FIG. 1 is a diagram showing an example of the circuit configuration of a defect presence / absence inspection section of a winding defect inspection apparatus according to embodiment 3. FIG. 2 is a block diagram showing the configuration of a winding defect inspection apparatus according to embodiment 4. FIG. 3 is a block diagram showing the configuration of a winding defect inspection apparatus according to embodiment 5. FIG. 4 is a diagram explaining the setting of a programmable resistor in a winding defect inspection apparatus according to embodiment 5. FIG. 5 is a diagram explaining the setting of a programmable resistor in a winding defect inspection apparatus according to embodiment 5. FIG. 6 is a block diagram showing the configuration of a winding defect inspection apparatus according to embodiment 6. FIG. 7 is a flowchart explaining the operation of a winding defect inspection apparatus according to embodiment 6. FIG. 8 is a diagram explaining a discharge current, a post-processing inspection signal, and a defect presence / absence signal detected by the winding defect inspection apparatus according to embodiment 6. FIG. 9 is a diagram explaining an example of the circuit configuration of a protection command generation means of a winding defect inspection apparatus according to embodiment 6. FIG. 10 is a block diagram showing the configuration of a winding defect inspection apparatus according to embodiment 7. FIG. 11 is a flowchart explaining the operation of a winding defect inspection apparatus according to embodiment 7.10 is a diagram illustrating a discharge current, a post-processing inspection signal, and a defect presence / absence signal detected by the winding defect inspection device according to embodiment 7. FIG. 11 is a diagram illustrating an example of the circuit configuration of a defect presence / absence inspection unit of the winding defect inspection device according to embodiment 7.

[0012] A preferred embodiment of a winding defect inspection device according to the present disclosure will be described below with reference to the drawings. The same contents and corresponding parts are designated by the same reference numerals, and detailed descriptions thereof will be omitted. Similarly, in the following embodiments, redundant descriptions of components designated by the same reference numerals will be omitted.

[0013] 1 is a block diagram of a defect inspection device for windings of a rotating electrical machine according to embodiment 1. The defect inspection device for windings 1 includes a winding machine main body 2 that winds the windings 1 around a wound member 11 to manufacture winding components for a rotating electrical machine, a defect inspection unit 3 for inspecting the windings 1, and a defect inspection and protection unit 4 for the windings 1.

[0014] The defect inspection unit 3 and the defect inspection and protection unit 4 are mainly composed of the following components (1) to (9). The defect inspection unit 3 detects defects in the winding 1, and the defect inspection and protection unit 4 prevents damage to the insulating layer 18 of the winding 1. (1) A sensor 5 is disposed on the path along which the winding 1 wound around the unwinding unit 10 travels while being given a constant tension by a tensioner 80 and reaches the wound member 11. (2) A power source 6 applies a voltage between the sensor 5 and the winding 1. (3) A voltage dividing means 14 divides the voltage of the power source 6 and applies a voltage between the winding 1 and a nozzle 16 that guides the winding 1 to the wound member 11. (4) A discharge current detecting means 7a detects a discharge current generated between the sensor 5 and a defective portion of the winding 1. (5) A discharge current detecting means 7b detects a discharge current generated between the nozzle 16 that guides the winding 1 to the wound member 11 and a flaw in the winding 1. (6) Inspection signal processing means 8a, 8b amplify the detection signals of the discharge current detection means 7a, 7b. (7) Defect presence / absence determination means 9a, 9b determine whether there is a defect or a flaw in the winding 1 based on the processed inspection signals of the inspection signal processing means 8a, 8b. (8) Programmable resistor 12 is disposed between the power supply 6 and the sensor 5, and programmable resistor 13 is disposed between the voltage dividing means 14 and the nozzle 16. (9) Condition setting unit 15 issues a resistance command to change the resistance values ​​of programmable resistors 12, 13 so that the discharge current represented by the processed inspection signal does not exceed a protection start threshold for protecting the winding.

[0015] Next, the discharge between the winding 1 and the sensor 5 will be described. For ease of explanation, the block diagram in FIG. 1 has been simplified to show the parts necessary for explanation in FIG. 2. In the configuration in FIG. 2, the GND terminal of the power supply 6 is connected to the portion of one end of the winding 1 where the insulating layer 18 is peeled off, and the voltage output terminal of the power supply 6 is connected to the sensor 5. When a voltage is applied to the sensor 5, if there is a defect 19 such as a scratch or pinhole in the insulating layer 18 of the winding 1, a discharge 20 will occur between the core 17 of the copper wire portion of the winding 1 and the sensor 5, and a current will flow in the circuit consisting of the power supply 6, the sensor 5, and the core 17 of the winding 1. In FIG. 3, the vertical axis represents the magnitude of the discharge current between the core 17 and the sensor 5, and the horizontal axis represents elapsed time.

[0016] The difficulties encountered when using a fixed resistor to inspect for defects 19 in the winding 1 as described above will be explained in detail with reference to Figures 2 and 3. The fixed resistor is, for example, 10 kΩ. Figure 3(a) shows the discharge signal detected by the discharge current detection means 7a when a high voltage of, for example, 1000 V is applied to the sensor 5 from the power supply 6. In this case, while a defect-free portion of the winding 1 passes under the sensor 5, no discharge occurs between the winding 1 and the sensor 5, so no discharge current flows, and the detection signal 21 of the discharge current detection means 7a is zero.

[0017] If the winding 1 has a large defect 19a, for example, with a width of 200 μm, then the discharge current detection means 7a will detect a detection signal 22a while the defect 19a passes under the sensor 5. On the other hand, if the winding 1 has a small defect 19b, for example, with a width of 50 μm, then the discharge current detection means 7a will detect a detection signal 23a while the defect 19b passes under the sensor 5.

[0018] 3(a) shows the discharge current threshold value 24 that destroys the insulating layer 18 of the winding 1. The discharge current detection means 7a can detect both large defects 19a and small defects 19b, but when detecting a large defect 19a, the detection signal 22a exceeds the destruction threshold 24, which may destroy the insulating layer 18 of the winding 1 and burn the insulating layer around the defect 19a.

[0019] In contrast, when a low voltage, for example, 300 V, is applied to the sensor 5 from the power supply 6, the discharge current detected by the discharge current detection means 7a is shown in Figure 3(b). Detection signals 22b and 23b are detected by the discharge current detection means 7a while a large defect 19a and a small defect 19b pass under the sensor 5. In this case, the detection signal 22b detecting the large defect 19a, for example, with a width of 200 μm, does not exceed the breakdown threshold 24 and therefore does not break down the insulating layer 18 of the winding 1. However, the detection signal 23b of a small defect 19b with a width of 50 μm becomes too small and may not be detected.

[0020] Even when a fixed resistor is used to detect flaws caused by friction between the nozzle 16 and the winding 1 shown in FIG. 1, it is difficult to achieve both reliable flaw detection and prevention of damage to the insulating layer 18 of the winding 1 for the same reasons as described above.

[0021] The principle and operation of defect inspection for winding 1 according to embodiment 1, which solves the problems associated with using fixed resistors, are described in detail below. The principle of this embodiment is to set low initial values ​​for programmable resistors 12 and 13 so that the discharge current does not exceed breakdown threshold 24, which would destroy insulating layer 18 of winding 1, when detecting defect 19 in winding 1, and to dynamically change the resistance of programmable resistors 12 and 13 using condition setting unit 15. This prevents breakdown of insulating layer 18 of winding 1 and enables highly reliable detection of defects and flaws in winding 1.

[0022] The operation will be described in detail below. Figure 4 shows a flowchart of the operation process of this embodiment. First, the setting of initial values ​​before inspection will be described. The condition setting unit 15 issues a voltage command to the power supply 6 to set the output voltage (step S1), and also issues a resistance command to the programmable resistors 12 and 13 to set initial resistance values ​​(step S2). Since the probability of detecting a defect in the winding 1 varies depending on the configuration of the sensor 5, the type and thickness of the winding 1, the tension applied to the winding 1, etc., the voltage command and resistance command may be set empirically or by taking statistics.

[0023] For example, the voltage of the power supply 6 is set to 600 V, the programmable resistor 12 and the sensor 5 detect defects 19 in the winding 1, the voltage of the power supply 6 is divided to 30 V by the voltage dividing means 14, and flaws in the winding 1 are detected by the programmable resistor 13 and the nozzle 16. In order to reliably detect flaws and flaws in the winding 1, in other words, to increase the probability of detection, it is better to set the initial values ​​of the programmable resistors 12 and 13 lower than the resistance value considered as the reference. In this embodiment, for example, the programmable resistor 12 is set to 1 kΩ and the programmable resistor 13 is set to 100 Ω.

[0024] Next, the operation when inspecting the winding 1 for defects 19 will be described. The winding machine main body 2, defect inspection unit 3, and defect inspection and protection unit 4 start operating, and defect inspection of the winding 1 begins (step S3). The discharge current between the sensor 5 and the winding 1 is detected by the discharge current detection means 7a (step S4), and the detected discharge current is amplified by the inspection signal processing means 8a (step S5). Figure 5(a) shows the detected discharge current. The vertical axis of Figure 5(a) represents the magnitude of the discharge current, and the horizontal axis represents the elapsed time. The operation of the defect inspection unit 3 and defect inspection and protection unit 4 will now be described using the detection of a defect in the winding 1 by the sensor 5 as an example.

[0025] [Operation of the Defect Inspection and Protection Unit] First, the operation of the defect inspection and protection unit 4 will be described. <When a large defect exists in the winding 1> If the winding 1 has a large defect, for example, 200 μm wide, a discharge occurs between the sensor 5 and the winding 1 as the defect passes under it, as explained in Figure 2, and a discharge current is detected as shown in Figure 5(a). When the discharge current reaches 15 μA at time t1, if detection is continued without changing the resistance value of the programmable resistor 12 and maintaining its initial value of 1 kΩ, the discharge current 38 flowing through the defect 19 in the winding 1 will continue to rise, as shown by the dashed line, and will exceed the breakdown threshold 24 (for example, 100 μA) at time t2, potentially destroying the insulating layer 18 of the winding 1.

[0026] To prevent such breakdown of the insulating layer 18, the defect detection and protection unit 4 operates as follows. First, the processed inspection signal 43 at time t1, which has been amplified by the inspection signal processing means 8a, is read into the condition setting unit 15 (step S6). The condition setting unit 15 then determines whether the discharge current exceeds the protection start threshold 40 (e.g., 10 μA) (step S7). The condition setting unit 15 compares the processed inspection signal with the protection start threshold. However, in this example, the comparison between the discharge current and the protection start threshold 40 will be described in terms of the relationship between the breakdown threshold and the discharge current. If the discharge current exceeds the protection start threshold 40, the condition setting unit 15 determines whether the resistance value of the programmable resistor 12 has been updated (step S8). If not, the condition setting unit 15 sends an updated resistance command to the programmable resistor 12, setting the resistance value of the programmable resistor 12 higher than the current value (step S9). For example, the resistance value of the programmable resistor 12 is updated from 1 kΩ to 1 MΩ. 5A, the discharge current does not reach the breakdown threshold 24 even at time t2. After the defect in the winding 1 passes under the sensor 5, the discharge current is no longer detected at time t3, so the amplitude becomes "0," indicating "no defect," and falls below the protection start threshold 40 (No in step S7). The condition setting unit 15 determines that the discharge current has become "0" based on the post-processing inspection signal (step S10), and returns the programmable resistor 12 to its initial value of 1 kΩ (step S11).

[0027] <When a Small Defect Exists in the Winding 1> Next, if the winding 1 has a small defect, for example, 50 μm wide, the discharge current 41 shown in Figure 5(a) is detected by the discharge current detection means 7a while the defect passes under the sensor 5. Because the discharge current 41 does not exceed the protection start threshold 40 (No in step S7, No in step S10), the resistance value of the programmable resistor 12 is not updated and the initial value of 1 kΩ is maintained.

[0028] In this way, during defect inspection, the protective action of the defect inspection and protection unit 4 can prevent destruction of the insulating layer 18 regardless of whether the defect in the winding 1 is large or small.

[0029] [Operation of the Defect Inspection Unit] Next, the operation of the defect inspection unit 3 will be described. As described above, the discharge currents 39 and 41 in FIG. 5(a) are amplified by the inspection signal processing means 8a and processed as the processed inspection signals 43 and 44 shown in FIG. 5(b) (step S5). The processed inspection signals 43 and 44 are then subjected to a defect determination by the defect determination means 9a. The defect threshold 42 is a threshold for determining the presence or absence of a defect. For example, the output value of the inspection signal processing means 8a at a discharge current of 5 μA is set as the threshold. The processed inspection signals 43 and 44 are then compared with the defect threshold 42 (step S12). Because the processed inspection signal 43 exceeded the defect threshold 42 between time t4 and time t5, it is determined that there is a defect in the winding 1 (Yes in step S13), and a high-level "H" signal 45 shown in FIG. 5(c) is output to the controller 78 of the winding machine main body 2 (step S14). Furthermore, between times t6 and t7, a defect was also found in winding 1, so a high level "H" signal 46 is output. In response to the high level "H" signal, controller 78 may take measures such as issuing an alarm sound or displaying a warning on a display.

[0030] The operation when inspecting for damage caused by friction between the nozzle 16 and the winding 1 is similar to that described above. A voltage dividing means 14 is provided to apply a voltage between the winding 1 and the nozzle 16, which guides the winding 1 to the wound member 11, or between the nozzle periphery 52 and the winding 1. A programmable resistor 13 is connected between the nozzle 16 and the voltage dividing means 14. When the discharge current detected by the discharge current detecting means 7b exceeds the protection start threshold of 10 μA, the condition setting unit 15 instructs the programmable resistor 13 to change its resistance so that its current resistance is higher, for example, to 1 MΩ. When the discharge current detected by the discharge current detecting means 7b does not exceed the protection start threshold of 10 μA, the resistance of the programmable resistor 13 is maintained at its initial value. When the discharge current exceeds the defect presence / absence threshold of 5 μA, the defect presence / absence determining means 9b outputs a high-level "H" signal to the controller 78. Since the discharge current is a very small current, it is amplified by the inspection signal processing means 8b and compared with the protection start threshold and defect presence / absence threshold.

[0031] <Circuit Examples of Components of the Defect Inspection / Protection Unit and Defect Presence / Absence Inspection Unit> Next, we will explain circuit examples of components of the defect inspection / protection unit 3 and the defect inspection / protection unit 4. Figure 6 shows an example of an equivalent circuit of the discharge current detection means 7a, the inspection signal processing means 8a, and the defect presence / absence determination means 9a.

[0032] The discharge current detection means 7a detects the discharge current flowing between the programmable resistor 12 and the sensor 5 using, for example, a shunt resistor 47. The inspection signal processing means 8a uses an amplifier 48 (generally referred to as an amplifier; surrounding components other than resistors are omitted) for signal amplification processing to amplify the voltage-converted discharge current. The defect presence / absence determination means 9a uses a comparator 49 (surrounding components are omitted) to compare the output of the amplifier 48 with a defect presence / absence threshold 42. When the output of the amplifier 48 is greater than the defect presence / absence threshold 42, the comparator 49 outputs a high-level "H" signal, for example, 5 V. When the output of the amplifier 48 is less than the defect presence / absence threshold 42, the comparator 49 outputs a low-level "L" signal, for example, 0 V (see FIG. 5(c)).

[0033] A filter (e.g., a low-pass filter) may be connected between the amplifier 48 and the comparator 49 to remove noise superimposed on the voltage-converted discharge current detected by the shunt resistor 47. Furthermore, an insulating means (e.g., a photocoupler) may be disposed between the shunt resistor 47 and the amplifier 48 to provide electrical insulation between the discharge current detecting means 7a and the inspection signal processing means 8a.

[0034] Similarly, the discharge current detection means 7b, the inspection signal processing means 8b, and the defect presence / absence determination means 9b may also be configured in the same manner as shown in Fig. 6. Although the components of each section are different, the operating principles are the same as those of the discharge current detection means 7a, the inspection signal processing means 8a, and the defect presence / absence determination means 9a described above.

[0035] The condition setting unit 15 is configured with a processor 100 and a storage device 110, as shown in an example of hardware in FIG. 7 . Although not shown, the storage device 110 includes a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory. Alternatively, a hard disk auxiliary storage device may be used instead of the flash memory. The processor 50 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), an integrated circuit (IC), a field programmable gate array (FPGA), various logic circuits, various signal processing circuits, and the like. Alternatively, multiple processors 100 of the same type or different types may be provided, and each process may be shared and executed.

[0036] The processor 50 executes a program input from the storage device 110. In this case, the program is input from the auxiliary storage device to the processor 100 via the volatile storage device. The processor 100 may output data such as calculation results to the volatile storage device of the storage device 110, or may store the data in the auxiliary storage device via the volatile storage device. Note that the device is not limited to a personal computer or a microcontroller, and may be anything that can output a resistance command.

[0037] 8, the voltage dividing means 14 divides the output voltage of the power supply 6 using resistors 50 and 51, and the resulting voltage is applied to the programmable resistor 13. The programmable resistors 12 and 13 may be variable resistors whose resistance value can be changed.

[0038] As another example, the resistance values ​​of the programmable resistors 12 and 13 may be changed using the following operations shown in FIGS. 9 and 10 . The details of this operation will be explained using the programmable resistor 12 as an example. When the discharge current exceeds the protection start threshold 40 (actually, when the post-processing inspection signal exceeds the protection start threshold) (step S7), the resistance value of the programmable resistor 12 is increased stepwise, as shown in FIG. 10 . For example, the resistance value is first changed from the initial value of 1 kΩ to 10 kΩ. If the discharge current still exceeds the protection start threshold 40, the programmable resistor 12 is changed from 10 kΩ to 100 kΩ. The above operation is repeated to change the programmable resistor 12 (step S15), controlling the discharge current so that it does not exceed the breakdown threshold 24. After that, after the defect 19 in the winding 1 passes under the sensor 5, the discharge current is no longer detected, so the amplitude becomes "0," representing "no defect," and falls below the protection start threshold 40 (Yes in step S10). The condition setting unit 15 determines from the detection signal that the discharge current has become "0" and resets the programmable resistor 12 to its initial value of 1 kΩ (step S11). This operation is repeated every time a defect 19 is detected.

[0039] As described above, large defects in the windings can be detected while the train is running, without damaging the insulation layer of the windings, and small defects and scratches can be detected with high reliability at the same time as large defects.

[0040] Embodiment 2. Fig. 11 is a block diagram of a defect inspection device for a winding of a rotating electrical machine according to embodiment 2. The same reference numerals as in Fig. 1 indicate the same or corresponding parts.

[0041] The defect inspection unit 3 and the defect inspection and protection unit 4 are mainly composed of the following components (1) to (11). The defect inspection unit 3 detects defects in the winding 1, and the defect inspection and protection unit 4 prevents damage to the insulating layer 18 of the winding 1. (1) Sensors 5a and 5b are arranged on the path along which the winding 1 wound around the unwinding unit 10 travels while being given a constant tension by a tensioner 80 and leads to the wound member 11. (2) A power source 6 applies a voltage between the sensors 5a and 5b and the winding 1. (3) A voltage dividing means 14 divides the voltage of the power source 6 and applies a voltage between the winding 1 and a nozzle 16 that guides the winding 1 to the wound member 11. (4) A discharge current detecting means 7a detects a discharge current generated between the sensor 5b and a defective portion of the winding 1. (5) A discharge current detecting means 7c detects a discharge current generated between the sensor 5a and a defective portion of the winding 1. (6) The discharge current detection means 7b detects a discharge current occurring between the nozzle 16 and a flaw in the winding 1. (7) The inspection signal processing means 8a, 8b, and 8c amplify the detection signals of the discharge current detection means 7a, 7b, and 7c. (8) The defect presence / absence determination means 9a, 9b, and 9c determine whether the winding 1 has a defect or a flaw based on the processed inspection signals of the inspection signal processing means 8a, 8b, and 8c. (9) The programmable resistor 12 is disposed between the power supply 6 and the sensor 5, and the programmable resistor 13 is disposed between the voltage dividing means 14 and the nozzle 16. (10) The condition setting unit 15 issues a resistance command to the programmable resistors 12 and 13 to change their resistance values ​​so that the discharge current represented by the processed inspection signal does not exceed a protection start threshold for protecting the winding. (11) A plurality of discharge current detection means may be disposed between the programmable resistor 13, the nozzle 16, and the nozzle periphery 52.

[0042] The difference between embodiment 2 and embodiment 1 is that, as described above, sensors 5a and 5b are arranged at different positions along the running direction of winding 1. Sensors 5a and 5b are arranged, for example, 10 cm apart. If the running speed of winding 1 is 500 mm / s, defect 19 in winding 1 passes under sensor 5a and then passes under sensor 5b 0.2 seconds later, and therefore the time difference between the processed inspection signals input to defect presence / absence determining means 9a and defect presence / absence determining means 9c is also 0.2 seconds.

[0043] The operation of the defect inspection device for winding 1 is the same as that described in embodiment 1, but there are the following differences due to the placement of multiple sensors. The operation of programmable resistor 12 will now be described. The processed inspection signals of inspection signal processing means 8 a, 8 c are read into condition setting unit 15, and if the discharge current represented by at least one of the processed inspection signals exceeds protection start threshold 40, the resistance value of programmable resistor 12 is changed using the operation described in embodiment 1.

[0044] The operation of the defect presence / absence determining means 9a, 9c will now be described. If either one of the defect presence / absence determining means 9a, 9c detects the defect presence / absence signal 45 or the defect presence / absence signal 46 shown in FIG. 5(c), the controller 78 determines that there is no defect 19 in the winding 1. Furthermore, if both the defect presence / absence determining means 9a and 9c detect the defect presence / absence signal 45 or the defect presence / absence signal 46 shown in FIG. 5(c), the controller 78 calculates the time difference between the defect presence / absence signal 45 and the defect presence / absence signal 46 of the defect presence / absence determining means 9a, 9c (e.g., the time difference between the rising edges of the defect presence / absence signals 45, 46). If the time difference is 0.2 seconds, the controller 78 determines that there is one defect 19 in the winding 1 and takes measures such as issuing an audio warning. On the other hand, if the time difference is not 0.2 seconds, the controller 78 determines that one of the sensors 5a, 5b has detected noise and determines that there is no defect 19 in the winding 1. It should be noted that the calculation takes into account delays in the device, such as measurement errors.

[0045] The defect inspection device of the second embodiment can also be applied to inspecting for scratches caused by friction between the nozzle 16 and the winding 1, and the operation and effects are similar to those of the above-mentioned case of inspecting for defects. In this way, in addition to the effects of the first embodiment, the defect inspection device of the second embodiment can improve the accuracy of detecting defects or scratches, and can more reliably prevent damage to the insulating layer of the winding.

[0046] Embodiment 3. Fig. 12 is a block diagram of a defect inspection device for a winding of a rotating electrical machine according to embodiment 3. In the figure, the same reference numerals as in Fig. 1 indicate the same or corresponding parts.

[0047] The defect inspection unit 3 and the defect inspection and protection unit 4 are mainly composed of the following components (1) to (9). The defect inspection unit 3 detects defects in the winding 1, and the defect inspection and protection unit 4 prevents damage to the insulating layer 18 of the winding 1. (1) The winding 1 wound around the unwinding unit 10 travels while being given a constant tension by the tensioner 80, and a sensor 5 is disposed on the path leading to the wound member 11. (2) A power supply 6 applies a voltage between the sensor 5 and the winding 1. (3) A power supply 53 applies a voltage between the winding 1 and a nozzle 16 that guides the winding 1 to the wound member 11. (4) A voltage detection means 54 detects a voltage drop due to a discharge current that occurs between the sensor 5 and a defective portion of the winding 1. (5) A voltage detection means 55 detects a voltage drop due to a discharge current that occurs between the nozzle 16 and a flaw in the winding 1. (6) Inspection signal processing means 8a, 8b perform noise processing on the detection signals of voltage detection means 54, 55. (7) Defect presence / absence determination means 9a, 9b determine whether there is a defect or a flaw in winding 1 based on the processed inspection signals of inspection signal processing means 8a, 8b. (8) Programmable resistor 12 is disposed between power supply 6 and sensor 5, and programmable resistor 13 is disposed between power supply 53 and nozzle 16. (9) Condition setting unit 15 issues a resistance command to programmable resistors 12, 13 to change their resistance values ​​so that the detection signal of the power supply voltage represented by the processed inspection signal does not fall below a protection start threshold for protecting the winding.

[0048] The configuration of the defect inspection device for winding 1 according to embodiment 3 is characterized by the provision of voltage detection means 54 for detecting the voltage of power supply 6 and voltage detection means 55 for detecting the voltage of power supply 53, as described above. Then, instead of detecting the discharge current between sensor 5 and winding 1 and the discharge current between nozzle 16 and winding 1, defects in winding 1 are inspected by detecting the voltage change of power supply 6 when a discharge occurs between sensor 5 and winding 1, and the voltage change of power supply 53 when a discharge occurs between nozzle 16 and winding 1. The operation of the defect inspection device according to this embodiment is the same as the process shown in FIG. 4 , except that the object to be detected is the voltage change of power supply 6 and power supply 53. Power supply 53 may apply a voltage of, for example, 30 V to nozzle 16.

[0049] [Operation of the Defect Inspection and Protection Unit] Next, detailed operation will be described with reference to the flowchart in Fig. 13, taking as an example a defect inspection of the winding 1 by detecting a change in voltage of the power supply 6. A voltage of, for example, 600 V is applied from the power supply 6 to the sensor 5. The voltage of the power supply 6 is detected by resistors 56 and 57 of the voltage detection means 54 (step S31), and noise processing and the like are performed by the inspection signal processing means 8a (step S32).

[0050] <When a large defect exists in the winding 1> When there is no defect in the winding 1, the voltage of the power supply 6 does not change, and the voltage signal 60 shown in Figure 14(a) is detected. The operation when the defect 19 in the winding 1 is large will be explained. If the winding 1 has a large defect, for example, 200 μm wide, a discharge occurs between the sensor 5 and the winding 1 as it passes under the sensor 5, and a discharge current flows suddenly. This causes the voltage of the power supply 6 to drop, and the voltage change is detected by the voltage detection means 54.

[0051] 14(a), at time t1, for example, the voltage drops from 600 V to 580 V, which is detected by the voltage detection means 54. At this time, if the resistance value of the programmable resistor 12 is not changed and is maintained at, for example, the initial value of 1 kΩ, the discharge current continues to increase and the voltage of the power supply 6 continues to decrease, as indicated by the dashed line voltage 61. There is a risk that the voltage of the power supply 6 will fall below a breakdown threshold 63 (for example, 200 V) that will destroy the insulating layer 18 of the winding 1, and the insulating layer 18 of the winding 1 will be destroyed.

[0052] To prevent breakdown of the insulating layer 18 of the winding 1, the defect detection and protection unit 4 operates as follows. First, the condition setting unit 15 reads the processed inspection signal at time t1, which is the detection signal of the inspection signal processing unit 8a with noise removed (step S33). Next, the condition setting unit 15 determines whether the voltage of the power supply 6 has fallen below the protection start threshold 64 (the protection start threshold 64 is, for example, 590 V) (step S34).

[0053] If the resistance value falls below the protection start threshold 64, it is determined whether the resistance of the programmable resistor 12 has been updated (step S35). If the resistance value has not been updated, the condition setting unit 15 updates the resistance command for the programmable resistor 12, and sets the resistance value of the programmable resistor 12 higher than the current value (step S36). For example, the resistance value of the programmable resistor 12 is increased to 1 MΩ. As a result, the voltage transitions as shown by the solid line in FIG. 14( a) as the detection signal 62 (noise is omitted). Even if the voltage drops at time t2, the voltage does not change as shown by the dashed line, and the breakdown threshold 63 is not reached.

[0054] Thereafter, after the defect in the winding 1 passes under the sensor 5, for example at time t3, the discharge current disappears (step S37), and the detected voltage becomes 600 V (amplitude when there is no defect), so the programmable resistor 12 is returned to its initial value of 1 kΩ (step S38).

[0055] <When a Small Defect Exists in the Winding 1> Next, we will explain the operation when the defect in the winding 1 is small. Suppose there is a small defect, for example, 50 μm wide, in the winding 1. While the defect passes under the sensor 5, a voltage 65 shown in FIG. 14(a) is detected, and because it does not fall below the protection start threshold 64, the resistance of the programmable resistor 12 is not updated and its initial value is maintained (No in step S34, No in step S37).

[0056] The above-described protective operation allows inspection of large defects in the running windings without detecting discharge current, preventing damage to the winding insulation layer 18, and also allows inspection of small defects and scratches at the same time as large defects with high reliability.

[0057] [Operation of Defect Inspection Unit] Next, the operation of the defect inspection unit 3 will be described. The detection signals 62 and 65 in FIG. 14(a) are subjected to noise removal by the inspection signal processing means 8a, and are sent to the defect judgment means 9a as processed inspection signals 67 and 68 shown in FIG. 14(b), where the defect judgment is performed. A threshold value for judging the presence or absence of a defect in the winding 1 is set to a defect threshold value 69. For example, the voltage of 600 V of the power supply 6 is converted to 10 V by the voltage detection means 54, and the defect threshold value 69 is set to 9.8 V. The processed inspection signals 67 and 68 in FIG. 14(b) are compared with the defect threshold value 69 (step S39). Because the processed inspection signal 67 fell below the defect threshold value 69 between times t4 and t5, it is judged that there is a defect in the winding 1 (Yes in step S40), and a high-level "H" signal 70 shown in FIG. 14(c) is output to the controller 78 of the winding machine main body 2 (step S41). Furthermore, a defect was also found in winding 1 between times t6 and t7, so high level "H" signal 71 is output. In response to the high level "H" signal, controller 78 may take measures such as issuing an alarm sound or displaying a warning on a display.

[0058] The operation when inspecting for damage caused by friction between the nozzle 16 and the winding 1 is similar to that described above. For example, when the voltage detected by the voltage detection means 55 falls below the protection start threshold of 25 V, the condition setting unit 15 instructs the programmable resistor 13 to have a resistance of 1 MΩ. When the voltage detected by the voltage detection means 55 does not fall below the protection start threshold of 25 V, the resistance of the programmable resistor 13 is left at its initial value. The voltage of 30 V from the power supply 53 may be converted to 10 V by the voltage detection means 55, and the damage threshold for the winding 1 may be set to 9.8 V to determine whether or not the winding 1 has a damage.

[0059] <Example of Circuits for Each Component of the Defect Inspection and Protection Unit and the Defect Presence / Absence Inspection Unit> Next, an example of circuits for each component of the defect inspection and protection unit 3 and 4 will be described. FIG. 15 shows an example of an equivalent circuit for the inspection signal processing means 8a and the defect presence / absence determination means 9a. The inspection signal processing means 8a uses a low-pass filter to remove noise from the detected voltage of the power supply 6. The processed inspection signal is sent to the condition setting unit 15 and the defect presence / absence determination means 9a. The defect presence / absence determination means 9a uses a comparator 72 (peripheral components omitted) to compare the processed inspection signal with a defect presence / absence threshold 69. When the processed inspection signal is smaller than the defect presence / absence threshold 69, the comparator 72 outputs a high-level "H" signal, for example, 5 V. When the processed inspection signal is larger than the defect presence / absence threshold 69, the comparator 72 outputs a low-level "L" signal, for example, 0 V. FIG. 14(c) schematically shows the output of the comparator 72. Furthermore, an insulating means (for example, a photocoupler) for electrical insulation may be disposed between the voltage detecting means 54 and the inspection signal processing means 8a to insulate the voltage detecting means 54 from the inspection signal processing means 8a.

[0060] Similarly, the voltage detection means 55, inspection signal processing means 8b, and defect presence / absence determination means 9b may also be configured as shown in Figure 15. Although the components of each section are different, the operating principle is the same as described above. Note that the above description is merely one example, and in order to further improve the reliability of detecting defects in the winding 1, multiple sensors 5 may be arranged along the running direction of the winding 1, as described in embodiment 2, and each sensor may detect a change in voltage of the power supply 6 when a discharge occurs between the winding 1 and the sensor, and change the setting of the programmable resistor 12.

[0061] As described above, it is possible to detect large defects in the windings while the train is running without detecting discharge current, while preventing damage to the insulation layer of the windings, and it is also possible to reliably detect small defects and scratches at the same time as large defects.

[0062] Embodiment 4. Figure 16 is a block diagram of a defect inspection device for a winding of a rotating electrical machine according to embodiment 4. In this figure, the same reference numerals as in Figure 1 indicate the same or corresponding parts.

[0063] The defect inspection unit 3 and the defect inspection and protection unit 4 are composed of the following components (1) to (8). The defect inspection unit 3 detects defects in the winding 1, and the defect inspection and protection unit 4 prevents damage to the insulating layer 18 of the winding 1. (1) A sensor 5 is disposed on a path along which the winding 1 wound around the unwinding unit 10 travels while being given a constant tension by a tensioner 80 and reaches the wound member 11. (2) Electromagnetic wave detection means 73a and 73b for detecting electromagnetic waves are disposed near the sensor 5 and the nozzle 16 that guides the winding 1 to the wound member 11, respectively. "Near" here means positioned close enough to detect electromagnetic waves. (3) A power source 6 applies a voltage between the sensor 5 and the winding 1. (4) A voltage dividing means 14 divides the voltage of the power source 6 and applies a voltage between the winding 1 and the nozzle 16 that guides the winding 1 to the wound member 11. (5) Inspection signal processing means 8a, 8b amplify the detection signals of the electromagnetic wave detection means 73a, 73b. (6) Defect presence / absence determination means 9a, 9b determine whether there is a defect or a flaw in the winding 1 based on the processed inspection signals of the inspection signal processing means 8a, 8b. (7) Programmable resistor 12 is disposed between power supply 6 and sensor 5, and programmable resistor 13 is disposed between voltage dividing means 14 and nozzle 16. (8) Condition setting unit 15 issues a resistance command to change the resistance values ​​of programmable resistors 12, 13 so that the current corresponding to the electromagnetic waves represented by the processed inspection signals does not exceed a protection start threshold for protecting the windings.

[0064] The operation of the defect inspection apparatus according to the fourth embodiment is the same as that described in the first embodiment except for the detection of electromagnetic waves by the electromagnetic wave detection means 73a and 73b, and therefore a description thereof will be omitted.

[0065] If there is a defect in the winding 1, a discharge occurs between the sensor 5 and the winding 1, causing a discharge current to flow and also emitting electromagnetic waves. These electromagnetic waves are detected by the electromagnetic wave detection means 73a, instead of detecting the discharge current as in embodiment 1, to inspect for defects in the winding 1. Similarly, when inspecting for damage caused by friction between the nozzle 16 and the winding 1, the electromagnetic waves are detected by the electromagnetic wave detection means 73b.

[0066] In order to further improve the reliability of detecting defects in the winding 1, a plurality of sensors 5 and electromagnetic wave detection means 73a may be arranged along the running direction of the winding 1, and each sensor may detect a plurality of electromagnetic waves emitted when a discharge occurs between the sensor and the winding 1, and the setting of the resistance value of the programmable resistor 12 may be changed.

[0067] In this way, by detecting the electromagnetic waves generated during discharge instead of the discharge current, it is possible to detect large defects in the windings while the train is running without damaging the insulation layer of the windings, and it is also possible to reliably detect small defects and scratches at the same time as large defects. Needless to say, detecting electromagnetic waves in addition to detecting the discharge current can improve detection accuracy.

[0068] Embodiment 5. Figure 17 is a block diagram of a defect inspection device for a winding of a rotating electrical machine according to embodiment 5. In the figure, the same reference numerals as in Figure 1 indicate the same or corresponding parts.

[0069] The defect inspection unit 3 and the defect inspection and protection unit 4 are composed of the following components (1) to (9). The defect inspection unit 3 detects defects in the winding 1, and the defect inspection and protection unit 4 prevents damage to the insulating layer 18 of the winding 1. (1) A sensor 5 is disposed on the path along which the winding 1 wound around the unwinding unit 10 travels while being given a constant tension by a tensioner 80 and reaches the wound member 11. (2) A power source 6 applies a voltage between the sensor 5 and the winding 1. (3) A voltage dividing means 14 divides the voltage of the power source 6 and applies a voltage between the winding 1 and a nozzle 16 that guides the winding 1 to the wound member 11. (4) A discharge current detecting means 7a detects a discharge current generated between the sensor 5 and a defective portion of the winding 1. (5) A discharge current detecting means 7b detects a discharge current generated between the nozzle 16 that guides the winding 1 to the wound member 11 and a flaw in the winding 1. (6) Inspection signal processing means 8a, 8b amplify the detection signals of the discharge current detection means 7a, 7b. (7) Defect presence / absence determination means 9a, 9b determine whether there is a defect or a flaw in the winding 1 based on the inspection signals processed by the inspection signal processing means 8a, 8b. (8) Programmable resistor 12 is disposed between the power supply 6 and the sensor 5, and programmable resistor 13 is disposed between the voltage dividing means 14 and the nozzle 16. (9) Condition setting unit 15 issues resistance commands for periodically changing the resistance values ​​of programmable resistors 12, 13.

[0070] The operating principle of this embodiment is that the defect inspection and protection unit 4 does not use the inspection signals processed by the inspection signal processing units 8a and 8b, but periodically and repeatedly changes the resistance values ​​of the programmable resistors 12 and 13. The operation of the defect presence / absence inspection unit 3 is the same as in the first embodiment, and therefore a description thereof will be omitted.

[0071] [Operation of Defect Inspection Protection Unit] The operation of the defect inspection protection unit 4 of this embodiment will be described. The principle of operation will be described using the programmable resistor 12 as an example. As shown in FIG. 18 , at time 74 within the period T, the resistance value of the programmable resistor 12 is set to a small value, for example, 1 kΩ. At time 75 within the period T, the resistance value of the programmable resistor 12 is set to a large value, for example, 1 MΩ. If there is a defect in the winding 1 at time 74, a discharge occurs because the programmable resistor 12 is small at 1 kΩ, and a discharge current 76 is detected. Thereafter, at time 75, the programmable resistor 12 is set to a large value, for example, 1 MΩ, so no discharge occurs and no discharge current is detected.

[0072] If the time it takes for defect 19 in winding 1 to pass under sensor 5 is, for example, 5 ms, and the period T in Fig. 16 is set to T = 2.5 ms, the discharge current can be detected twice while the defect in winding 1 passes under sensor 5, thereby increasing the probability of detecting defect 19 in winding 1. Time 74 may be set to, for example, 20% of period T. Similarly, the resistance value of programmable resistor 13 may be changed periodically and repeatedly.

[0073] As shown in FIG. 19 , the resistance values ​​of programmable resistors 12 and 13 may be increased stepwise over time 74. For example, programmable resistor 12 may be increased stepwise between its initial value and a predetermined resistance value at which the winding insulation is not broken down, such as 1 kΩ, 10 kΩ, . . . 1 MΩ. Furthermore, to further improve the reliability of detecting defects in winding 1, as in embodiment 2, multiple sensors 5 may be arranged along the running direction of winding 1, and each sensor may detect a discharge current when a discharge occurs between winding 1 and programmable resistor 12, and the resistance value of programmable resistor 12 may be changed accordingly. Furthermore, instead of detecting the discharge current, as in embodiment 3, voltage changes in power supplies 6 and 53 may be detected and used by defect inspection unit 3. Furthermore, instead of detecting the discharge current, as in embodiment 4, voltage changes in power supplies 6 and 53 may be detected and used by defect inspection unit 3. Furthermore, instead of detecting the discharge current, as in embodiment 4, electromagnetic waves generated during discharge may be detected and used by defect inspection unit 3.

[0074] In this way, defects in the windings, whether large or small, or even scratches, can be reliably detected while preventing damage to the winding insulation layer during operation.

[0075] Sixth Embodiment A switch may be used instead of a programmable resistor as a means for protecting the insulating layer of the winding. Figure 20 is a block diagram of a defect inspection device for a rotating electrical machine winding according to a sixth embodiment. In the figure, the same reference numerals as those in the first embodiment indicate the same or corresponding parts.

[0076] 20 , the defect inspection unit 3 and the defect inspection and protection unit 4 are mainly composed of the following components (1) to (9). The defect inspection unit 3 detects defects in the winding 1, and the defect inspection and protection unit 4 prevents damage to the insulating layer 18 of the winding 1. (1) A sensor 5 is disposed on the path along which the winding 1 wound around the unwinding unit 10 travels while being given a constant tension by a tensioner 80 and reaches the wound member 11. (2) A power source 6 applies a voltage between the sensor 5 and the winding 1. (3) A voltage dividing means 14 divides the voltage of the power source 6 and applies a voltage between the winding 1 and a nozzle 16 that guides the winding 1 to the wound member 11. (4) A discharge current detecting means 7a detects a discharge current generated between the sensor 5 and a defective portion of the winding 1. (5) Discharge current detection means 7b detects a discharge current generated between the nozzle 16, which guides the winding 1 to the wound member 11, and the location of a flaw in the winding 1. (6) Inspection signal processing means 8a, 8b convert the voltage of the detection signals from the discharge current detection means 7a, 7b and amplify them. (7) Defect presence / absence determination means 9a, 9b determine whether there is a defect or flaw in the winding 1 based on the processed inspection signals from the inspection signal processing means 8a, 8b. (8) Switch 81 is disposed between the power source 6 and the sensor 5, and switch 82 is disposed between the voltage dividing means 14 and the nozzle 16. (9) Protection command generation means 83 outputs an open / close command to instruct the switches 81, 82 to turn on or off so that the discharge current represented by the processed inspection signal does not exceed a protection start threshold for protecting the winding.

[0077] The difference between embodiment 6 and embodiment 1 is that, as described above, the defect inspection protection unit 4 does not change the resistance values ​​of programmable resistors 12 and 13, but instead protects winding 1 by turning on and off switches 81 and 82 that are arranged therein so that the discharge current does not exceed the breakdown threshold.

[0078] The operation will be described in detail below. Figure 21 shows a flowchart of the operation process of this embodiment. First, the setting of initial values ​​before inspection will be described. The output voltage of power supply 6 is set (step S1B), and a command to turn switches 81 and 82 on (closed) is output from protection command generating means 83 (step S2B). After that, winding machine main body 2, defect presence / absence inspection unit 3, and defect inspection / protection unit 4 begin operating, and defect inspection of winding 1 begins (step S3B).

[0079] [Operation of the Defect Inspection and Protection Unit] First, the operation of the defect inspection and protection unit 4 will be described. <When a large defect exists in the winding 1> If the winding 1 has a large defect, for example, 200 μm wide, a discharge occurs between the sensor 5 and the winding 1 as the defect passes under it, as explained in Figure 2, and a discharge current is detected as shown in Figure 22(a). When the discharge current reaches 15 μA at time t1, if detection continues while the switch 81 is left on without changing its state, the discharge current 38B flowing through the defect 19 in the winding 1 will continue to rise, as shown by the dashed line, and may exceed the breakdown threshold 24 (for example, 100 μA), potentially destroying the insulating layer 18 of the winding 1.

[0080] To prevent such breakdown of the insulating layer 18, the defect detection and protection unit 4 operates as follows. First, the processed inspection signal 43B at time t1, which has been voltage-converted and amplified by the inspection signal processing means 8a, is read into the protection command generating means 83 (step S6B). The protection command generating means 83 then determines whether the discharge current exceeds the protection start threshold 40 (e.g., 10 μA) (step S7B). The protection command generating means 83 compares the processed inspection signal with the protection start threshold. However, this explanation focuses on the comparison between the discharge current and the protection start threshold in light of the relationship between the breakdown threshold and the discharge current. If the discharge current exceeds the protection start threshold 40, the protection command generating means 83 outputs an OFF (open) protection command to the switch 81, turning the switch 81 off and interrupting the path between the power supply 6 and the sensor 5 (step S8B). Interrupting the path between the power supply 6 and the sensor 5 also interrupts the discharge current (the detection signal becomes 0), causing it to fall below the protection start threshold 40. When the discharge current falls below the protection start threshold 40, the switch 81 is turned on again (step S10B), and if the defect has not passed the sensor 5, the discharge current flows again. In this manner, the switch is repeatedly turned on and off until the defect in the winding 1 passes under the sensor 5. In this state, the discharge current may exceed the protection start threshold 40, but it will not reach the breakdown threshold 24. After the defect in the winding 1 passes under the sensor 5, at time t2, the discharge current is no longer detected, so it becomes "0," indicating an amplitude of "no defect," and falls below the protection start threshold 40 (No in step S7B). The protection command generating means 83 determines that the discharge current has become "0" based on the post-processing inspection signal (step S9B), and turns the switch 81 back on (step S10B).

[0081] Next, if the winding 1 has a small defect, for example, 50 μm wide, a discharge current 41 shown in FIG. 22(a) is detected by the discharge current detection means 7a while the defect passes under the sensor 5. Because the discharge current 41 does not exceed the protection start threshold 40 (No in step S7B, No in step S9B), the switch 81 remains on.

[0082] In this way, during defect inspection, the protective action of the defect inspection and protection unit 4 can prevent destruction of the insulating layer 18 regardless of whether the defect in the winding 1 is large or small.

[0083] [Operation of Defect Inspection Unit] Next, the operation of the defect inspection unit 3 will be described. As described above, the discharge currents 39B and 41B in FIG. 22(a) are amplified by the inspection signal processing means 8a and processed as processed inspection signals 43B and 44B shown in FIG. 22(b) (step S5B). The processed inspection signals 43B and 44B are then subjected to a defect determination by the defect determination means 9a. The defect presence / absence threshold 42 is a threshold for determining the presence or absence of a defect, and is set, for example, to the output value of the inspection signal processing means 8a when the discharge current is 5 μA. The processed inspection signals 43B and 44B are then compared with the defect presence / absence threshold 42 (step S11B). Between times t4 and t5, post-processing inspection signal 43B exceeded defect presence / absence threshold 42B, so it was determined that there was a defect in winding 1 (Yes in step S12B), and a high level "H" signal 45 shown in Figure 22(c) was output to controller 78 of winding machine main body 2 (step S13B). Also, between times t6 and t7, there was a defect in winding 1, so a high level "H" signal 46B was output. In response to the high level "H" signal, controller 78 may take measures such as issuing an audible warning or displaying a warning on a display.

[0084] The operation when inspecting for damage caused by friction between the nozzle 16 and the winding 1 is similar to that described above. A voltage dividing means 14 is provided to apply a voltage between the winding 1 and the nozzle 16, which guides the winding 1 to the wound member 11, or between the nozzle periphery 52 and the winding 1. A switch 82 is connected between the nozzle 16 and the voltage dividing means 14. When the discharge current detected by the discharge current detecting means 7b exceeds the protection start threshold of 10 μA, a protection command generating means 83 outputs a command to turn off the switch 82. When the discharge current detected by the discharge current detecting means 7b does not exceed the protection start threshold of 10 μA, the switch 82 remains on. When the discharge current exceeds the defect presence / absence threshold of 5 μA, a high-level "H" signal is output from the defect presence / absence determining means 9b to the controller 78. Note that because the discharge current is a very small current, it is amplified by the inspection signal processing means 8b and compared with the protection start threshold and the defect presence / absence threshold.

[0085] The circuits of the discharge current detection means 7a, inspection signal processing means 8a, and defect presence / absence determination means 9a are the same as those shown in Fig. 6, but the output of the discharge current detection means 7a is directed to switches 81 and 82, and the processed inspection signal is directed to protection command generation means 83. Similarly, the discharge current detection means 7b, inspection signal processing means 8b, and defect presence / absence determination means 9b may also be configured in the same manner as shown in Fig. 6. Although the components of each section are different, the operating principles are the same as those of the discharge current detection means 7a, inspection signal processing means 8a, and defect presence / absence determination means 9a described above.

[0086] An example of the configuration of the protection command generating means 83 is shown in Figure 23. The processed inspection signal is input to one input terminal of the comparator 34 (surrounding components are omitted), and a preset protection start threshold 40 is input to the other input terminal. When the value of the processed inspection signal exceeds the protection start threshold 40, the output of the comparator 34 becomes low (L), turning off (opening) the switch 81 or the switch 82. When the value of the processed inspection signal is less than the protection start threshold 40, the output of the comparator 34 becomes high (H), turning on (closing) the switch 81 or the switch 82. The protection command generating means 83 may include two circuits shown in Figure 23, with the output side of the comparator 34 connected to the switch 81 and the switch 82, respectively.

[0087] The voltage dividing means 14 has the same configuration as that shown in FIG. 8, and the output voltage of the power supply 6 is divided by resistors 50 and 51 and the divided voltage is applied to a switch 82 .

[0088] The switches 81 and 82 may be implemented using electronic devices such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors).

[0089] As described above, a simple circuit configuration using a switch and a comparator can detect large defects in the windings while the train is running, while preventing damage to the winding insulation layer, and can also reliably detect small defects and scratches at the same time as large defects.

[0090] Embodiment 7. Figure 24 is a block diagram of a defect inspection device for a winding of a rotating electrical machine according to embodiment 7. In the figure, the same reference numerals as in Figure 1 indicate the same or corresponding parts.

[0091] The defect inspection unit 3 and the defect inspection and protection unit 4 are mainly composed of the following components (1) to (9). The defect inspection unit 3 detects defects in the winding 1, and the defect inspection and protection unit 4 prevents damage to the insulating layer 18 of the winding 1. (1) The winding 1 wound around the unwinding unit 10 travels while being given a constant tension by the tensioner 80, and a sensor 5 is disposed on the path leading to the wound member 11. (2) A power supply 6 applies a voltage between the sensor 5 and the winding 1. (3) A power supply 53 applies a voltage between the winding 1 and a nozzle 16 that guides the winding 1 to the wound member 11. (4) A voltage detection means 54 detects a voltage drop due to a discharge current that occurs between the sensor 5 and a defective portion of the winding 1. (5) A voltage detection means 55 detects a voltage drop due to a discharge current that occurs between the nozzle 16 and a flaw in the winding 1. (6) Inspection signal processing means 8a, 8b perform noise processing on the detection signals of the discharge current detection means 7a, 7b. (7) Defect presence / absence determination means 9a, 9b determine whether the winding 1 has a defect or a flaw based on the processed inspection signals of the inspection signal processing means 8a, 8b. (8) Switch 81 is disposed between the power supply 6 and the sensor 5, and switch 82 is disposed between the power supply 53 and the nozzle 16. (9) Protection command generation means 83 outputs opening / closing commands to instruct the switches 81, 82 to turn on or off so that the discharge current represented by the processed inspection signal does not fall below a protection start threshold for protecting the windings.

[0092] The configuration of the defect inspection device for winding 1 according to embodiment 7 is characterized by the provision of voltage detection means 54 for detecting the voltage of power supply 6 and voltage detection means 55 for detecting the voltage of power supply 53, as described above. Then, instead of detecting the discharge current between sensor 5 and winding 1 and the discharge current between nozzle 16 and winding 1, defects in winding 1 are inspected by detecting the voltage change of power supply 6 when a discharge occurs between sensor 5 and winding 1, and the voltage change of power supply 53 when a discharge occurs between nozzle 16 and winding 1. The operation of the defect inspection device according to this embodiment is the same as the process shown in Figure 20, except that the object to be detected is the voltage change of power supply 6 and power supply 53. Power supply 53 may apply a voltage of, for example, 30 V to nozzle 16.

[0093] [Operation of the Defect Inspection and Protection Unit] Next, detailed operation will be described with reference to the flowchart in Fig. 25, taking as an example defect inspection of the winding 1 by detecting a change in voltage of the power supply 6. A voltage of, for example, 600 V is applied from the power supply 6 to the sensor 5. The voltage of the power supply 6 is detected by resistors 56 and 57 of the voltage detection means 54 (step S31B), and noise processing and the like are performed by the inspection signal processing means 8a (step S32B).

[0094] <When a large defect exists in the winding 1> When there is no defect in the winding 1, the voltage of the power supply 6 does not change, and the voltage signal 60B shown in Figure 26(a) is detected. The operation when the defect 19 in the winding 1 is large will be explained. If the winding 1 has a large defect, for example, 200 μm wide, a discharge occurs between the sensor 5 and the winding 1 as it passes under the sensor 5, and a discharge current flows suddenly. This causes the voltage of the power supply 6 to drop, and the voltage change is detected by the voltage detection means 54.

[0095] 26(a), at time t1, for example, the voltage drops from 600 V to 580 V, which is detected by the voltage detection means 54. If the switch 81 remains on (closed) at this time, the discharge current continues to rise, and the voltage of the power supply 6 continues to drop, as indicated by the dashed line voltage 61B. The voltage of the power supply 6 falls below a breakdown threshold 63 (e.g., 200 V) that breaks down the insulating layer 18 of the winding 1, and there is a risk that the insulating layer 18 of the winding 1 will be destroyed.

[0096] To prevent breakdown of the insulating layer 18 of the winding 1, the defect detection and protection unit 4 operates as follows. First, a processed inspection signal at time t1, which is a detection signal from the inspection signal processing means 8a with noise removed, is input to the protection command generating means 83 (step S33B). The comparator 34 detects whether the voltage of the power supply 6 has fallen below the protection start threshold 64 (the protection start threshold 64 is, for example, 590 V) (step S34B).

[0097] If the voltage falls below the protection start threshold 64, the switch 81 is turned off (open) (step S35B), cutting off the path between the power supply 6 and the sensor 5. Cutting off the path between the power supply 6 and the sensor 5 also cuts off the discharge current, causing the voltage of the power supply 6 to exceed the protection start threshold 64. If the voltage exceeds the protection start threshold 64, the switch 81 turns on again, and if the defect has not passed the sensor 5, the discharge current flows again. In this manner, the switch is repeatedly turned on and off until the defect in the winding 1 passes under the sensor 5. In this state, the power supply voltage transitions as indicated by the detection signal 62B shown by the solid line, and although it may fall below the voltage of the protection start threshold 64, it does not change as indicated by the voltage 61B shown by the dashed line, and does not reach the voltage of the breakdown threshold 63.

[0098] Thereafter, after the defect in the winding 1 passes under the sensor 5, for example at time t2, the discharge current disappears and the detected voltage becomes 600 V (amplitude when there is no defect) (step S36B), so the switch 81 is turned back on (step S37B).

[0099] <When a Small Defect Exists in the Winding 1> Next, we will explain the operation when the defect in the winding 1 is small. Suppose there is a small defect, for example, 50 μm wide, in the winding 1. While the defect passes under the sensor 5, a voltage 65 shown in FIG. 26(a) is detected, and because it does not fall below the protection start threshold 64, the switch 81 is maintained in the on state (No in step S34B, No in step S36B).

[0100] The above-described protective operation allows inspection of large defects in the windings while the train is running, without detecting discharge current, while preventing damage to the winding insulation layer, and also allows inspection of small defects and scratches at the same time as large defects with high reliability.

[0101] [Operation of Defect Inspection Unit] Next, the operation of the defect inspection unit 3 will be described. The detection signals 62B and 65B in FIG. 26(a) are subjected to noise removal by the inspection signal processing means 8a, and are sent to the defect presence / absence determination means 9a as processed inspection signals 67B and 68B shown in FIG. 26(b), where the presence or absence of a defect is determined. A threshold value for determining the presence or absence of a defect in the winding 1 is set to a defect presence / absence threshold value 69. For example, the voltage of 600V of the power supply 6 is converted to 10V by the voltage detection means 54, and the defect presence / absence threshold value 69 is set to 9.8V. The processed inspection signals 67B and 68B in FIG. 26(b) are compared with the defect presence / absence threshold value 69 (step S38B). Between times t4 and t5, there are locations where post-processing inspection signal 67B falls below defect presence / absence threshold 69, so it is determined that there is a defect in winding 1 (Yes in step S39B), and a high-level "H" signal 70B shown in Figure 26(c) is output to controller 78 of winding machine main body 2 (step S40B). Also, between times t6 and t7, there was a defect in winding 1, so a high-level "H" signal 71B is output. In response to the high-level "H" signal, controller 78 may take measures such as issuing an audible warning or displaying a warning on a display.

[0102] The operation when inspecting for damage caused by friction between the nozzle 16 and the winding 1 is similar to that described above. For example, when the voltage detected by the voltage detection means 55 falls below the protection start threshold of 25 V, the protection command generation means 83 outputs an output to turn the switch 82 off (open). When the voltage detected by the voltage detection means 55 does not fall below the protection start threshold of 25 V, the switch 82 is maintained in the on (closed) state. The voltage of 30 V from the power supply 53 may be converted to 10 V by the voltage detection means 55, and the threshold for determining whether the winding 1 is damaged may be set to 9.8 V.

[0103] <Example of Circuits for Each Component of the Defect Inspection and Protection Unit and the Defect Presence / Absence Inspection Unit> Next, an example of circuits for each component of the defect inspection and protection unit 3 and 4 will be described. FIG. 27 shows an example of an equivalent circuit for the inspection signal processing means 8a and the defect presence / absence determination means 9a. The inspection signal processing means 8a uses a low-pass filter to remove noise from the detected voltage of the power supply 6. The processed inspection signal is sent to the protection command generating means 83 and the defect presence / absence determination means 9a. The defect presence / absence determination means 9a uses a comparator 72 (peripheral components omitted) to compare the processed inspection signal with a defect presence / absence threshold 69. When the processed inspection signal is smaller than the defect presence / absence threshold 69, the comparator 72 outputs a high-level "H" signal, for example, 5 V. When the processed inspection signal is larger than the defect presence / absence threshold 69, the comparator 72 outputs a low-level "L" signal, for example, 0 V. FIG. 26(c) schematically shows the output of the comparator 72. Furthermore, an insulating means (for example, a photocoupler) for electrical insulation may be disposed between the voltage detecting means 54 and the inspection signal processing means 8a to insulate the voltage detecting means 54 from the inspection signal processing means 8a.

[0104] Similarly, the voltage detection means 55, inspection signal processing means 8b, and defect presence / absence determination means 9b may also be configured as shown in Figure 27. Although the components of each section are different, the operating principle is the same as described above. Note that the above description is merely one example, and in order to further increase the reliability of detecting defects in the winding 1, multiple sensors 5 may be arranged along the running direction of the winding 1, as described in embodiment 2, and each sensor may detect a change in voltage of the power supply 6 when a discharge occurs between the sensor and the winding 1, and control the on / off of the switch 81.

[0105] As described above, it is possible to detect large defects in the windings while the train is running without detecting discharge current, while preventing damage to the insulation layer of the windings, and it is also possible to reliably detect small defects and scratches at the same time as large defects.

[0106] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in the specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0107] 1: Winding, 2: Winding machine body, 3: Defect presence / absence inspection section, 4: Defect inspection and protection section, 5, 5a, 5b: Sensor, 6, 53: Power supply, 7a, 7b, 7c: Discharge current detection means, 8a, 8b, 8c: Inspection signal processing means, 9a, 9b, 9c: Defect presence / absence determination means, 10: Unwinding section, 11: Wound member, 12, 13: Programmable resistor, 14: Voltage dividing means, 15: Condition setting section, 16: Nozzle, 17: Core, 18: Insulating layer, 19, 19a, 19b: Defect, 20: Discharge, 52: Nozzle periphery, 54, 55: Voltage detection means, 78: Controller, 80: Tensioner, 81, 82: Switch, 83: Protection command generation means

Claims

1. 1. A defect inspection device for a winding, which runs with a constant tension applied to it in order to be wound around a wound member, the device comprising: a sensor arranged on a running path of the winding to the wound member; a power source which applies a voltage between the sensor and the winding; a first programmable resistor connected between the sensor and the power source; a first discharge current detection means which detects a first discharge current generated between the sensor and the winding by applying the voltage; a first defect inspection unit which determines whether or not there is a defect in the winding based on a result of comparing the first discharge current with a predetermined defect presence / absence threshold; and a condition setting unit which, while determining the presence or absence of a defect by the first defect inspection unit, instructs an increase in the resistance value of the first programmable resistor when the first discharge current exceeds a predetermined protection start threshold.

2. 2. The winding defect inspection device according to claim 1, further comprising: a voltage dividing means for the power supply that applies a voltage between the winding and a nozzle that guides the winding to the wound member; a second programmable resistor connected between the nozzle and the voltage dividing means; a second discharge current detection means that detects a second discharge current generated between the nozzle and the winding by applying a voltage by the voltage dividing means; a second defect inspection unit that determines whether or not there is a flaw in the winding based on a result of comparing the second discharge current with a predetermined defect presence / absence threshold; and while the second defect inspection unit is determining whether or not there is a flaw, if the second discharge current exceeds a predetermined protection start threshold, an instruction to increase the resistance value of the second programmable resistor is given from the condition setting unit.

3. 1. A defect inspection device for a winding, which runs with a constant tension in order to be wound around a wound member, the device comprising: a sensor arranged on a running path of the winding to the wound member; a first power supply which applies a voltage between the sensor and the winding; a first programmable resistor connected between the sensor and the first power supply; a first voltage detection means which detects a voltage of the first power supply; a first defect inspection unit which determines whether or not there is a defect in the winding based on a result of comparing the voltage detected by the first voltage detection means with a predetermined defect presence / absence threshold; and a condition setting unit which, while determining the presence or absence of a defect by the first defect inspection unit, instructs an increase in the resistance value of the first programmable resistor if the voltage detected by the first voltage detection means falls below a predetermined protection start threshold.

4. 4. The winding defect inspection device according to claim 3, further comprising: a second power supply that applies a voltage between the winding and a nozzle that guides the winding to the wound member; a second programmable resistor connected between the nozzle and the second power supply; second voltage detection means that detects a voltage of the second power supply; a second defect presence / absence inspection unit that determines whether or not there is a flaw in the winding based on a result of comparing the voltage detected by the second voltage detection means with a predetermined defect presence / absence threshold; and while the second defect presence / absence inspection unit is determining whether or not there is a flaw, if the voltage detected by the second voltage detection means falls below a predetermined protection start threshold, an instruction to increase the resistance value of the second programmable resistor is given from the condition setting unit.

5. 1. A defect inspection device for a winding, which runs with a constant tension applied to it in order to be wound around a wound member, the device comprising: a sensor arranged on a running path of the winding to the wound member; a power source which applies a voltage between the sensor and the winding; a first programmable resistor connected between the sensor and the power source; first electromagnetic wave detection means which detects a first electromagnetic wave generated between the sensor and the winding by applying the voltage; a first defect inspection unit which determines whether or not there is a defect in the winding based on a result of comparing the first electromagnetic wave with a predetermined defect presence / absence threshold; and a condition setting unit which, while determining the presence or absence of a defect by the first defect inspection unit, instructs an increase in the resistance value of the first programmable resistor when the first electromagnetic wave exceeds a predetermined protection start threshold.

6. 6. The winding defect inspection device according to claim 5, further comprising: a voltage dividing means for the power supply that applies a voltage between the winding and a nozzle that guides the winding to the wound member; a second programmable resistor connected between the nozzle and the voltage dividing means; a second electromagnetic wave detection means that detects a second electromagnetic wave generated between the nozzle and the winding by applying a voltage by the voltage dividing means; a second defect inspection unit that determines whether or not there is a flaw in the winding based on a result of comparing the second electromagnetic wave with a predetermined defect presence / absence threshold; and while the second defect inspection unit is determining whether or not there is a flaw, if the second electromagnetic wave exceeds a predetermined protection start threshold, an instruction to increase the resistance value of the second programmable resistor is given from the condition setting unit.

7. 3. The winding defect inspection device according to claim 1 or 2, characterized in that a plurality of the sensors are arranged along a running path of the winding, and defects in the winding are determined based on the results of comparing a plurality of discharge currents with the defect presence / absence threshold value.

8. 3. The winding defect inspection device according to claim 1, wherein a plurality of the sensors are arranged along a running path of the winding, and the condition setting unit instructs a change in the resistance value of the first programmable resistor based on a result of comparing a plurality of discharge currents with the protection start threshold.

9. 7. The apparatus for inspecting a winding defect according to claim 1, wherein the resistance value of the programmable resistor is increased in stages.

10. a first programmable resistor connected between the sensor and the power supply; first discharge current detection means for detecting a discharge current generated between the sensor and the winding by applying the voltage; a first defect inspection unit for determining whether or not there is a defect in the winding based on a result of comparing the discharge current with a predetermined defect presence / absence threshold; and a condition setting unit for periodically changing the resistance value of the first programmable resistor between an initial value and a predetermined resistance value at which insulation of the winding is not broken down while the first defect inspection unit is determining the presence or absence of a defect.

11. 11. The winding defect inspection device according to claim 10, wherein the resistance value of the first programmable resistor is variable in a stepwise manner between an initial value and a predetermined resistance value at which insulation of the winding is not broken down.

12. 11. The winding defect inspection device according to claim 10, further comprising: a voltage dividing means for the power supply that applies a voltage between the winding and a nozzle that guides the winding to the wound member; a second programmable resistor connected between the nozzle and the voltage dividing means; a second discharge current detection means that detects a discharge current generated between the nozzle and the winding by applying a voltage by the voltage dividing means; a second defect inspection unit that determines whether or not there is a flaw in the winding based on a result of comparing the discharge current with a predetermined defect presence / absence threshold; and a condition setting unit that periodically changes a resistance value of the second programmable resistor between an initial value and a predetermined resistance value at which insulation of the winding is not broken down while the second defect inspection unit determines the presence or absence of a flaw.

13. 13. The winding defect inspection device according to claim 12, wherein the resistance value of the second programmable resistor is variable in a stepwise manner between an initial value and a predetermined resistance value at which insulation of the winding is not broken down.

14. a programmable resistor connected between the nozzle and the power supply; a discharge current detection means for detecting a discharge current generated between the nozzle and the winding by applying the voltage; a defect inspection unit for determining whether or not there is a flaw in the winding based on the result of comparing the discharge current with a predetermined defect presence / absence threshold; and a condition setting unit for instructing an increase in the resistance value of the programmable resistor when the discharge current exceeds a predetermined protection start threshold while determining the presence or absence of a flaw by the defect inspection unit.

15. The defect inspection device for a winding which runs under a constant tension in order to be wound around a wound member includes a sensor disposed on a running path of the winding leading to the wound member, a power source which applies a voltage between the sensor and the winding, a first switch which is connected between the sensor and the power source, a first discharge current detection means which detects a first discharge current which is generated between the sensor and the winding by applying the voltage, a first defect inspection unit which judges whether or not there is a defect in the winding based on a result of comparing the first discharge current with a predetermined defect threshold value, the winding comprises: protection command generating means for outputting a command to the first switch to cut off the first discharge current when the first discharge current exceeds a predetermined protection start threshold; voltage dividing means for applying a voltage between the winding and a nozzle that guides the winding to the wound member; a second switch connected between the nozzle and the voltage dividing means; second discharge current detecting means for detecting a second discharge current generated between the nozzle and the winding by applying a voltage by the voltage dividing means; and a second defect inspection unit for determining the presence or absence of a flaw in the winding based on a result of comparing the second discharge current with a predetermined defect threshold, A winding defect inspection device in which, while the second defect inspection unit determines the presence or absence of scratches, if the second discharge current exceeds a predetermined protection start threshold, the protection command generating means outputs a command to the second switch to cut off the second discharge current.

16. a first voltage detection means for detecting a voltage of the first power supply; a first defect inspection unit for determining whether or not a defect is present in the winding based on a result of comparing the voltage detected by the first voltage detection means with a predetermined defect presence / absence threshold; and protection command generating means for outputting a command to the first switch to shut off the sensor and the first power supply when the voltage detected by the first voltage detection means falls below a predetermined protection start threshold while determining the presence or absence of a defect by the first defect inspection unit.

17. 17. The winding defect inspection device according to claim 16, further comprising: a second power supply that applies a voltage between the winding and a nozzle that guides the winding to the wound member; a second switch connected between the nozzle and the second power supply; second voltage detection means that detects a voltage of the second power supply; a second defect presence / absence inspection unit that determines whether or not there is a flaw in the winding based on a result of comparing the voltage detected by the second voltage detection means with a predetermined defect presence / absence threshold; and while the second defect presence / absence inspection unit is determining whether or not there is a flaw, if the voltage detected by the second voltage detection means falls below a predetermined protection start threshold, the second switch cuts off the nozzle and the second power supply in response to a command from the protection command generating means.

18. 17. The apparatus for inspecting a winding for defects according to claim 1, wherein the protection start threshold is greater than the defect presence / absence threshold.

19. 17. The winding defect inspection device according to claim 1, wherein the protection start threshold is smaller than a breakdown threshold, which is a threshold of a discharge current that breaks down an insulating layer of the winding.