JP2000275310A - Method and device for inspecting stator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily diagnose the defective spot of a winding. SOLUTION: A pair of magnets 13a and 13b is arranged circumferentially at a prescribed angle along a stator 2 in such a manner that the magnets 13a and 13b are faced oppositely to each other in the diametric direction of the stator 2. In the event that the electromotive forces generated in a stator coil 22 at the positions facing the magnets 13a and 13b compensate each other when the magnets 13a and 13b are rotated at a fixed speed along the circumferential direction of the stator 2, it is discriminated that no layer exists at the positions of the coil 22 facing the magnets 13a and 13b. At the time of detecting the difference between the electromotive forces generated in the coil 22 at the positions facing the magnets 13a and 13b, the presence of layers is specified in the coil 22 at the positions facing the magnets 13a and 13b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator inspection method and an inspection apparatus for diagnosing and specifying an electrical insulation state of a winding wound on a stator of a rotating electric machine or the like and a defective electrical insulation.

[0002]

2. Description of the Related Art In general, when diagnosing the insulation state of a winding, a withstand voltage test for applying a high voltage to ground insulation is performed,
We also conduct tests to measure the current that flows when a DC voltage is applied to ground insulation using a megger tester.

[0003]

However, in these tests, an overvoltage is applied to the ground insulation to diagnose the state of the ground insulation from the presence or absence of insulation breakdown and the magnitude of the leakage current.
It is not possible to identify a rare part of the winding.

As a method of diagnosing a rare phase between or within windings, a method of testing by applying an overvoltage to the winding is known, and a rare tester is commercially available as a test apparatus for realizing this. ing. The rare tester can detect even a wrong wire connection or an incorrect number of turns, but cannot specify a rare part of the winding.

[0005] For this reason, it has been difficult to repair defective parts of windings having defective insulation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a method and an apparatus for inspecting a stator, in which a defective portion of a winding can be easily diagnosed.

[0007]

According to the first aspect of the present invention, there is provided a method for inspecting a stator (2) in which a stator coil (22) is wound around a cylindrical stator core (21). And a stator coil (22)
Magnetic field supply means (13a, 13b, 16, 30, 3, 3) that can supply a magnetic field to the
0a, 30b, 40) to detect a portion to which a magnetic field is supplied by the magnetic field supply means and to measure an electromotive force generated in the stator coil (22) at a portion to which the magnetic field is supplied by the magnetic field supply means. The stator coil (2
It is characterized in that the insulation failure part of 2) is specified.

According to this, by supplying a magnetic field to the stator coil while changing the magnetic flux over time, it is possible to generate an electromotive force in the stator coil at the magnetic field supply site. Then, if there is poor electrical insulation in the portion of the stator coil to which the magnetic field is supplied, the electromotive force decreases,
By detecting the magnetic field supply site and measuring the electromotive force generated in the stator coil at the magnetic field supply site, it is possible to detect the electrical insulation failure of the stator coil and specify the electrical insulation failure location.

According to the second aspect of the present invention, a large number of field coils are arranged in the circumferential direction of the stator coil (22) so as to face the stator coil (22), and flow for each of the large number of field coils. By controlling the current, an electromotive force can be generated for each stator coil (22) located at a position facing the field coil.

According to the third aspect of the present invention, the field coil disposed opposite to the stator coil (22) is rotated along the circumferential direction of the stator (2) in an excited state,
An electromotive force can be generated in the stator coil (22).

According to a fourth aspect of the present invention, the permanent magnet disposed to face the stator coil (22) is rotated along the circumferential direction of the stator (2) to form the stator coil (22). An electromotive force can be generated.

According to the fifth aspect of the present invention, a magnetic field is supplied to the stator coil (22), and an electromotive force generated in the stator coil (22) at a portion to which the magnetic field is supplied is measured. It is characterized by comparing with a voltage.

[0013] According to this, by comparing the voltage of the electromotive force generated in the stator coil at the magnetic field supply site with the reference voltage, it is possible to specify the location of the poor electrical insulation.

According to the sixth aspect of the invention, the magnetic field supply means supplies a magnetic field to one location in the circumferential direction of the stator coil (22), and a magnetic field generated in the stator coil (22) at the location where the magnetic field is supplied. It is characterized in that the power is measured and the integral value of the electromotive force time is compared with a set value.

According to this, since the integral value of the electromotive force is compared with the set value, a subtle difference in the electromotive force is also determined by the waveform of the electromotive force-time graph due to the difference in the inductance of the stator coil. For example, it is possible to determine a delicate difference, and it is possible to more accurately detect an electrical insulation failure of the stator coil and specify a location of the electrical insulation failure.

According to the seventh aspect of the present invention, the magnetic field supply means simultaneously supplies a magnetic field to two locations in the same phase of the stator coil (22), and generates an electromotive force generated at two locations of the stator coil (22). When canceling each other, it is determined that there is no insulation failure at two locations of the stator coil (22), and when detecting a difference between electromotive forces generated at two locations of the stator coil (22), the stator coil (22) is determined. 2)
It is characterized in that it is specified that there is insulation failure at a location.

According to this, the electromotive force is detected only when there is an electrical insulation failure at the magnetic field supply site. Therefore, even if the value of the electromotive force at each position of the magnetic field supply site is not accurately measured, the position of the electrical insulation failure site can be detected. Can be specified.

In a place where there is no electrical insulation failure,
The magnetic poles of the magnetic field supply means (13a, 13b) in the radial direction of the magnetic field supply means (13a, 13b) as described in claim 8, in order for the electromotive forces generated in the stator coils (22) at the two magnetic field supply portions to cancel each other. Are reversed at two locations of the stator coil (22), respectively.
The winding directions at the two locations in 2) may be the same.

In a place where there is no electrical insulation failure,
In order for the electromotive forces generated in the two stator coils (22) to cancel each other out, the magnetic poles of the magnetic field supply means (13a, 13b) in the radial direction of the core are required. Direction of the stator coil (22)
At the same location, the stator coil (2
The winding directions of the two places in 2) may be reversed.

According to a tenth aspect of the present invention, an electromotive force of each phase coil of the stator coil (22) formed by connecting the three-phase coils is measured to identify a defective electrical insulation portion. Can be.

Also, as in the invention according to claim 11,
The three-phase coils of the Y-connected stator coil (22) are paired in two-phase pairs, and the electromotive force of the coils is measured, so that the location of poor electrical insulation can be specified.

In the twelfth aspect of the present invention, the anti-neutral side of only one coil phase of the multi-phase coils is grounded, and the electromotive force is measured at the anti-neutral side of the other coil phases. The power measuring means (17) is connected to measure the electromotive force.

According to this, it is possible to detect not only the electrical insulation failure in the same phase of the stator coil but also the electrical insulation failure in the ground of the stator coil and the electrical insulation between the phases as follows.

That is, in the case of electrical insulation failure in the same phase, the electromotive force at the location of electrical insulation failure is reduced by the number of turns where electrical insulation failure has occurred. Therefore, by measuring the electromotive force, it is possible to detect electrical insulation failure in the same phase.

In the case of the earth to ground, an electromotive force is detected between the portion to which the electromotive force measuring means is connected and the earth portion, but the electromotive force is measured between the earth portion and the ground portion by the electromotive force measuring device. Since no power is detected, the ground point can be specified.

In the case of poor electrical insulation between the phases, no current flows in the short-circuited coil portion in the two coil phases in which electrical insulation failure occurs, and therefore, by measuring the electromotive force, the phase between the phases is determined. Electrical insulation failure can be detected.

According to a thirteenth aspect of the present invention, the neutral point of the polyphase coil is grounded, and the electromotive force measuring means (17) for measuring the electromotive force on the anti-neutral side of each coil phase.
Are connected, the same effect as the invention according to claim 12 can be obtained.

The invention according to claim 15 is characterized in that a constant bias voltage is applied to the ground side circuit of the coil.

According to this, it is possible to prevent erroneous determination due to voltage fluctuation due to noise or the like.

According to the present invention, the stator coil (22) includes a plurality of partial windings (221a, 221b,
221c), and the partial windings (221a,
221b, 221c), and based on the detected partial electromotive force, the partial winding (221a,
221b, 221c) is detected.

According to the seventeenth aspect of the present invention, a plurality of partial windings (221) constituting the stator coil (22) are provided.
a, 221b, 221c) in order to detect the both-end electromotive force at both ends where a plurality of partial windings are connected and to detect the two-end electromotive force corresponding to each magnetic field supply position,
It is characterized in that it is set as a partial electromotive force.

According to this, since the partial electromotive force for each partial winding is detected, it is easy to detect which partial winding has an electrical insulation failure.

[0033] According to the invention described in claim 18, according to the stator inspection method according to any one of claims 1 to 17, the location of defective insulation of the stator coil (22) is specified, and the insulation treatment is performed on the location of defective insulation. Is added to eliminate insulation failure.

[0034] According to this, by the stator inspection method according to any one of the first to seventeenth aspects, a defective electrical insulation can be specified. For this reason, in the past, when it was not possible to identify the defective electrical insulation, the defective product was discarded. However, if the electrical insulation defective portion is subjected to insulation treatment, the stator can be repaired.

According to the nineteenth aspect of the present invention, there is provided an inspection apparatus for a stator (2) in which a stator coil (22) is wound around a cylindrical stator core (21), wherein a magnetic field is supplied to the stator coil (22). And a magnetic field supply means (13) capable of changing the magnetic flux over time.
a, 13b) for detecting a portion supplying a magnetic field to the stator coil (22).
40) and an electromotive force measuring means (17) for measuring an electromotive force generated in the stator coil (22).

According to this method, as in the method according to the first aspect, the portion of the stator coil to which the magnetic field is supplied and the electromotive force corresponding thereto are measured, so that the rare portion of the stator coil can be specified. Becomes possible.

According to a twentieth aspect of the present invention, the magnetic field supply means includes a plurality of field coils (30) arranged facing the stator coil (22) and a current flowing for each of the plurality of field coils. And the current control means (40) for controlling the electric field, it is possible to generate an electromotive force for each stator coil (22) at a position facing the field coil.

According to the twenty-first aspect of the present invention, the magnetic field supply means includes a field coil (30a, 30b), and a turning mechanism for rotating the field coil along the circumferential direction of the stator (2) in an excited state. With the configuration including the means (16), an electromotive force can be generated in the stator coil (22).

According to the present invention, the magnetic field supply means includes permanent magnets (13a, 13b), and the turning means (16) for rotating the permanent magnets along the circumferential direction of the stator (2). , The stator coil (2
2) An electromotive force can be generated.

According to the twenty-third aspect of the present invention, the magnetic field supply means is disposed opposite to two places in the same phase of the stator coil (22) to supply a magnetic field to the stator coil (22). The members (13a, 13b, 30a, 30
b) and turning means (16) for rotating the pair of field members along the circumferential direction of the stator (2).

According to this method, the electromotive force is detected only when there is an electrical insulation failure in the magnetic field supply part, similarly to the method described in claim 7, so that the value of the electromotive force at each position of the magnetic field supply part is determined. Even if the measurement is not performed accurately, it is possible to specify the location of the electrical insulation failure.

In a place where there is no electrical insulation failure,
25. A pair of field members (13a, 13b, 30) according to claim 24, in order for the electromotive forces generated in the stator coils (22) at the two magnetic field supply sites to cancel each other.
a, 30b) by reversing the directions of the magnetic poles in the radial direction,
Stator coil (22) facing a pair of field members
May be set to the same winding direction.

Further, in a place where there is no electrical insulation defect,
26. A pair of field members (13a, 13b, 30) as described in claim 25, in order for the electromotive forces generated in the stator coils (22) at the two magnetic field supply sites to cancel each other.
a, 30b) have the same direction of the magnetic poles in the radial direction, and have the stator coils (2) facing the pair of field members.
The winding directions in 2) may be reversed.

According to a twenty-sixth aspect of the present invention, the magnetic field supply means rotates one field member (13a, 30a) and the one field member along the circumferential direction of the stator (2). With this configuration, the electromotive force can be generated in the stator coil (22).

The invention according to claim 27 is characterized in that a comparing means (51) for comparing the integral value of the time of the electromotive force with the set value is provided.

According to this, since the integral value of the electromotive force is compared with the set value, it is easy to determine even a slight difference in the electromotive force, and it is possible to more accurately detect the electrical insulation failure of the stator coil, and It is possible to specify a defective insulation portion.

According to a twenty-eighth aspect of the present invention, a comparison means (19) for comparing the voltage of the electromotive force with the reference voltage is provided.

According to this, by comparing the electromotive force generated in the stator coil at the magnetic field supply site with the reference voltage, it is possible to specify the location of poor electrical insulation.

According to the twenty-ninth aspect, the electromotive force of each phase coil of the stator coil (22) formed by connecting the three-phase coils is measured to identify a defective electrical insulation portion. Can be.

According to a thirtieth aspect of the present invention, the three-phase coils of the Y-connected stator coil (22) are paired in two-phase pairs, and the electromotive force of the coils is measured to identify the location of the poor electrical insulation. be able to.

The field member in this specification refers to a member capable of supplying a magnetic field, such as a permanent magnet or a field coil.

The symbols in parentheses above indicate the correspondence with specific means described in the embodiments described later.

[0053]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention.

(First Embodiment) FIG. 1 is an overall external view of an inspection device for a stator, and FIG. 2 is a schematic diagram showing an arrangement state of magnets on the inner peripheral side of the stator in an insulation diagnosis device.

The stator 2 to be diagnosed by the insulation diagnosing device 1 includes a stator core 21 and a stator coil 22. The stator core 21 has a cylindrical shape, and has 36 slots formed at equal intervals so that the stator coil 22 can be accommodated therein.

The stator coil 22 is U-shaped or I-shaped.
It is formed by joining a plurality of U-shaped conductor segments. The conductor segments are joined together on the stator core 21 with at least one joint within the magnetic pole pitch. These joints are arranged along one axial end of the stator core 21.

In this embodiment, the stator core 21 has 3
Phase coils are provided, and each phase is Y-connected to form a stator coil 22. In the present embodiment,
As shown in FIG. 2, the stator coil 22 is formed by lap winding. The lap-wound stator coil 22 is composed of a lap-wound portion as a plurality of partial windings. In each phase, for example, a straight portion of a wrapped winding is disposed on a 36-slot stator core 21 every three slots, and the X-phase and Y-phase, the Y-phase and Z-phase, and the Z-phase and X-phase each have Are shifted from each other.

A pedestal 11 on which the stator 2 is disposed is provided above the insulation diagnostic device 1. In the center of the pedestal portion 11, a magnet rotating portion 12 that projects in a cylindrical shape is provided. Two permanent magnets (field members) 13a and 13b are arranged on the outer peripheral portion of the magnet rotating portion 12 in the circumferential direction.
They are arranged at symmetrical positions separated by 0 °. In addition,
The magnet 13a is arranged such that the N pole faces the outer periphery, and the magnet 13b is arranged such that the S pole faces the outer periphery. That is, the directions of the magnetic poles of the magnets 13a and 13b are reversed. When the stator 2 is placed on the pedestal 11, the inner peripheral surface of the stator 2 and the magnets 13a and 13b are separated by a predetermined distance. The magnets 13a and 13b are preferably strong, and are made of ferrite in this embodiment.

The insulation diagnostic apparatus 1 has a DC motor power supply 15, and the DC motor power supply 15
DC motor (swing means) 16 installed in the lower part of 2
It is connected to the. Then, the magnet rotating unit 12 is rotated at a high speed (750 rpm in the present embodiment) in the direction of arrow A by the DC motor 16.

The insulation diagnosing device 1 includes the stator coil 2
It has three connection clips 14X, 14Y, 14Z that can be connected to each of the two three-phase ends 22X, 22Y, 22Z. End 22 of each phase of Y-connected stator coil 22
X, 22Y and 22Z are connecting clips 14X, 1
The measuring instrument (electromotive force measuring means) 17 is connected via 4Y and 14Z. Further, the connection part 14e is connected to the insulation diagnostic device 1
Is connected to the measuring instrument 17 and the measuring instrument 17 is grounded.

FIG. 3 is a circuit diagram of the stator coil 22 in the measuring device 17 according to the present embodiment. In the circuit according to the present embodiment, the electromotive force is measured between the X and Y phases and between the Y and Z phases of the stator coil 22 by the known voltmeter 17b. Switching between the X-phase and the Y-phase and between the Y-phase and the Z-phase is performed by a select switch 17 a in the measuring instrument 17. In the present embodiment, the Y-phase end 22Y
A bias voltage of 3 V is applied to the (ground side circuit) to drift 3 V to the plus side. The measurement result measured by the measuring instrument 17 is transmitted to a judgment display 19 connected to the measuring instrument 17.
Will be displayed.

Next, the operation of the insulation diagnostic device 1 will be described. In general, if Φ is the magnetic flux penetrating through the N-turn winding, E is the induced electromotive force, k is a constant, and t is time,

[0063]

It is known that E = kNdΦ / dt holds, and the electromotive force E is proportional to the number of turns N and the speed of change of the magnetic flux Φ. From this, if the speed of change of the magnetic flux Φ is constant under a certain winding, the number of turns N
Change, the electromotive force E changes. Therefore, if a magnet is moved under a certain winding, an electromotive force E is generated by the Fleming's right-hand rule. If there is a rare case, it is estimated that the number of turns N in that part is changed, and the electromotive force changes. it can.

The magnet rotating part 12 located on the inner peripheral part of the stator 2 is driven by a DC motor 16 at a constant speed by an arrow A.
Rotated in the direction of. Since two magnets 13 a and 13 b are provided on the outer periphery of the magnet rotating unit 12, an electromotive force is generated by rotating the magnet rotating unit 12. The electromotive force generated in the stator coil 22 is measured by the measuring device 17 and displayed on the judgment display 19.

The outer circumferential side of the magnet rotating unit 12 is
Magnets 13a and 13b arranged at positions separated by 0 °
Has the opposite direction of the magnetic pole. Further, the stator coils 22 provided in the 36 slots formed at equal intervals are:
At positions 180 ° apart, the winding directions of the coils are the same. Here, the same winding direction means that
° Stator coil 22 installed in remote slot
When an equal change in magnetic flux is applied to the stator core, a current flows in the same axial direction of the stator core 21 due to generation of an electromotive force.

In the present embodiment, the magnets 13a and 13b arranged at positions 180 ° apart from each other have opposite magnetic poles, so that the electromotive forces generated near the respective magnets cancel each other. As a result, when the normal stator coil 22 which is not rare is measured, the judgment display 19 shows a constant value as shown in FIG. When the normal stator coil 22 is measured, the electromotive force measures 0 V. However, since the Y-phase end 22Y has drifted 3 V to the positive side as described above, the judgment display 19 indicates 3 V. I have. The reason why the Y-phase end 22Y drifts to the plus side is to make it easier to find a grounding point as described later.

On the other hand, if the stator coil 22 has an in-phase rare, the number of turns is reduced at the rare location, and the electromotive force changes. In this case, when the electromotive force is measured in the stator coil 22 having the rare portion 22d in FIG.
When one of the magnets 13a, 13b located 80 ° apart passes through the rare spot 22d, the electromotive force generated by the two magnets 13a, 13b located 180 ° apart is not canceled out by each other, and Only an output waveform as shown in FIG. 5 is obtained. Here, the interval between the Min value and the Max value of the electromotive force is 30 ° which is the same slot interval. The quality of the product (stator) is determined by the Min value of the electromotive force, M
A judgment value (± 0.5 V in this embodiment) is provided for the ax value. If the change in the electromotive force is within the judgment value, the product is judged to be normal. If the change in the electromotive force exceeds the judgment value, the product is abnormal. Judge that there is.

The location of the rare portion when the stator coil 22 is rare is identified by the rotation position signal from the magnet rotating section 12. Since the magnets 13a and 13b are arranged at positions separated by 180 °, the pair of the Max value and the Min value that deviate from the determination value during one rotation of the magnet rotating unit 12 is two.
Is measured at each point. However, since the magnets 13a and 13b that are 180 ° apart are arranged so that the directions of the magnetic poles are reversed, a rare portion can be specified by the change in the waveform and the winding specification. That is, in the present embodiment, when the magnet 13a whose N pole faces the outer peripheral side passes through a place where there is a rare and the number of turns is reduced, the magnet 13a changes to a minus side when approaching the rare place. When it moves away from the rare spot, it changes to the plus side. Conversely, when the magnet 13b whose south pole faces the outer circumference passes through a rare and reduced number of turns, the magnet 13b changes to a plus side when approaching the rare location, It changes to the minus side when moving away from the.

More specifically, the specification of a rare part is performed as follows. The rotational position of the magnet is obtained from a signal from an encoder (excitation position detecting means) 18 attached to the DC motor. The encoder 18 applies a position signal trigger according to the slot position of the measurement phase, and if the Min value and the Max value position of the electromotive force are obtained, the rare portion can be specified. For example, when measuring the stator core 21 of 36 slots, a position signal trigger is applied 36 times per 360 degrees, that is, every 10 degrees, and after detecting the Min value of the electromotive force, the Max value is detected with respect to the trigger after 30 degrees. Then, it can be specified that there is a rare point between the slots where the Min value and the Max value are detected.

In the present embodiment, when the magnets 13a and 13b pass through a normal portion having no rare, the electromotive force is constant at 0 (3 V due to drift in measurement). In order to identify the rare spot, the Min value and Max
The exact value of the value is not required. That is, it is only necessary to detect a change from a fixed value to a plus side or a minus side by a predetermined value (0.5 V in the present embodiment) or more. Therefore, magnet 1
High accuracy is not required for the measurement of the rotational positions 3a and 13b. In the case of the 36-slot stator 2 as in the present embodiment, even if there is an error of about ± 3 °, it can be detected.

In a configuration in which a plurality of conductor segments are joined to form a stator coil as in this embodiment, a failure in these joints may cause a partial change in electromotive force of the coil. . For example, a short circuit between two adjacent junctions may reduce the electromotive force of the coil within one pole pitch. In this embodiment, by observing the electromotive force at both ends of the stator coil 22 in correspondence with the supply position of the field magnetic flux, a failure in a part of the series of stator coils 22 can be detected.

When the ground between the stator coil 22 and the stator core 21 is grounded, that is, in the state shown in the circuit diagram of FIG. 7, the electromotive force changes as shown in FIG. In the case of the circuit diagram shown in FIG. 7, since the stator core 21 is grounded in the X phase, what is measured by the measuring unit 17 is a portion Xb between the ground point and the end 22X of the X phase. This is the generated electromotive force. In the present embodiment, the two magnets 13a and 13b are provided in the Xa portion and the Xb portion located 180 ° apart in the circumferential direction of the stator core 21.
The positive and negative waveforms appear because the electromotive forces generated in the above do not cancel each other out. Further, in the present embodiment, measurement was performed by drifting to the plus side of 3 V at the Y-phase end portion 22Y. However, if there is a ground point, the drift cannot be performed, and the electromotive force waveform at the normal point decreases as shown in FIG. . Therefore, when a waveform that does not drift appears, it is known that the waveform is grounded.

Next, when there is an interphase rare in the stator coil 22, for example, as shown in FIG. 8, when there is a rare between the X phase and the Y phase, the Xa from the rare point of the X phase to the neutral point 22N. And the neutral point 22
No current flows through the coil portion of Ya up to N because it is short-circuited.

On the other hand, when one of the pair of magnets 13a and 13b 180 ° apart is located at the portion Xa and the other is located at the portion Xb, the two magnets 13a , 13b do not cancel each other out, the X-phase in-phase voltage is
(Upper row). Also, a pair of magnets 13a,
When one of the magnets 13b is located at the portion Ya and the other is located at the portion Yb, the electromotive force generated by the two magnets 13a and 13b 180 ° apart is not canceled out by each other. The in-phase voltages of the phases are as shown in FIG. 9 (middle stage). What is detected by the voltmeter 17b is the sum of the in-phase voltages of the X phase and the Y phase, as shown in FIG.
The output waveform of the electromotive force as shown in FIG. Note that since the X phase and the Y phase are shifted by one slot,
The in-phase voltages of the phase and the Y phase have a phase difference θd of one slot.

By measuring between the X phase and the Y phase and between the Y phase and the Z phase, the X phase, the Y phase, and the Z phase are all measured. When the Y-phase is defective, defects can be found both in the X-Y phase and in the Y-Z phase. In other words, between the X phase and the Y phase, the Y phase
After the measurement between the Z phases, if a defect is found twice, the Y phase is defective, and once, the X phase or the Z phase is defective.

The ground point can be specified by applying a position signal trigger corresponding to the X-phase, Y-phase, and Z-phase slot positions.

As described above, since the rare portion of the stator coil 22 can be specified, the stator 2 can be reworked by inserting an insulating member such as an insulating paper, an insulating film, or a nonwoven fabric into the rare portion and performing insulation treatment. . As a result, the stator 2 that has been discarded when a defective portion cannot be specified in the past can be reworked and used.

(Second Embodiment) In the first embodiment, a pair of magnets 13a and 13b are arranged at symmetrical positions 180 ° apart in the circumferential direction of the outer peripheral portion of the magnet rotating section 12. However, even if only one magnet is arranged in the magnet rotating unit 12, a rare part can be specified as follows.

In the second embodiment, only the magnet 13a whose N pole faces outward is arranged on the outer peripheral portion of the magnet rotating unit 12, and the magnet 13b whose S pole faces outward is not arranged. Other configurations are the same as those of the first embodiment.

FIG. 10 is a schematic development view of a stator coil, and FIG. 11 is a view showing an electromotive force generated in a winding. FIG.
0 indicates a coil 221 of one phase among the multi-phase stator coils 22. The coil 221 is formed on the stator coil 21 as a series of windings connected to a plurality of partial windings 221a, 221b, 221c for each magnetic pole pitch. In FIG. 10, only three overlapping winding portions are shown for simplicity. In FIG. 10, the front side of the drawing is the outer peripheral side of the stator 2. Therefore, the magnet 13a has the N pole on the near side of the drawing and the S pole on the opposite side, and the magnet 13a moves on the far side of the drawing of the stator coil.

The stator coil 221 in FIG. 10 is a lap winding, and 221a, 221b and 221c respectively form lap windings as partial windings of the winding stator coil 221. In addition, the overlapping winding part 221a is a rare part 221d.
have.

When the magnet rotating section 12 is rotated in the direction of arrow A in FIG. 1, that is, when the magnet 13a is moved rightward at a constant speed in FIG. 10, the inspection field is superposed as a partial winding. The power is supplied to each of the winding portions 221a, 221b, and 221c to generate an electromotive force. In FIG. 10, when the magnet 13a approaches the overlapping winding portions 221b and 221c, as shown in FIG. 11, positive electromotive forces Vb and Vc are generated. Further, when the magnet 13a moves away from the overlapping winding portions 221b and 221c, negative electromotive forces -Vb and -Vc are generated.

That is, the magnet 13a sequentially magnetizes a plurality of partial windings and generates a partial electromotive force for each partial winding. Then, by detecting the electromotive force induced in the partial winding, a failure such as rare in the partial winding can be detected.

The field for inspection is generated by moving the magnet 13a along the axial direction or circumferential direction of the stator 2 so as to change the direction of the magnetic flux or magnetic field interlinking the partial winding. . Further, in detecting the electromotive force of the partial winding, it is necessary to specify the partial winding to which the magnetic field is supplied. For example, when an electromotive force is observed at both ends of a series of windings including a plurality of partial windings, a configuration including a device for detecting a position supplying a magnetic field is employed. Observe Further, the electromotive force may be detected for each partial winding.

In the second embodiment shown in FIG. 10, the coil 221 of one phase has a plurality of partial windings 22 as a plurality of partial windings at every magnetic pole pitch over the entire circumference of the stator core 21.
1a, 221b and 221c are formed. And
The magnet 13a as a single field pole is
, The magnetic field is sequentially supplied to the plurality of windings. Then, by observing the electromotive force output to both ends of the one-phase coil 221 in correspondence with the position of the magnet 13a, it is possible to specify the partial winding where the abnormal electromotive force is observed.

The detection includes a DC motor (slewing means) 16 for rotatingly driving the magnet 13a, an encoder (excitation position detecting means) 18 for detecting the rotational position in correspondence with the position of the partial winding of the stator core 21, and It is composed of a measuring device (electromotive force measuring means) 17 for detecting the dielectric electromotive force of the coil, and a judgment display 19 for specifying a fault location based on the outputs of the encoder 18 and the measuring device 17 and displaying or indicating the fault. .

[0086] Lap winding portion 221 having rare portion 221d
In a, the number of turns of the overlapping winding portion 221a is reduced by the rare. Therefore, the overlapping winding parts 221b, 221c
Even when the magnet 13a is moved at a constant speed similar to the case described above, the electromotive force generated when the magnet 13a approaches and goes away from the overlapping winding portions 221b and 221c becomes smaller. As a result, the electromotive force generated in the winding 221 when the magnet 13a passes through the inside of the winding 221 is as shown in FIG.

(Third Embodiment) In the first and second embodiments, permanent magnets are used for the magnets 13a and 13b.
As in the third embodiment shown in FIG. 12, a field coil can be used instead of a permanent magnet.

FIG. 12 schematically shows the configuration of the magnet rotating unit 12 and the like, and the configuration of a portion not shown is the same as in the first embodiment. Two field coils (field members) 30a, 3
0b is a coil 302 attached to a core 301 made of a ferromagnetic material such as iron.
And is built in the magnet rotating unit 12. The coil 302 is connected to the power supply 15 via the brush 31 and the slip ring 32. The core 301 is magnetized by passing a current through the coil 302.
Are exposed at positions 180 ° apart from the circumferential surface of the magnet rotating unit 12. The magnet rotating unit 12 including the field coils 30a and 30b is configured to be rotated by a DC motor (turning means) 16.

Thus, while the insulation diagnostic apparatus 1 is operating, a current is applied to the coil 302 (ie, the field coil 3
When the magnet rotating unit 12 is rotated (when the magnets 0a and 30b are excited), an N-pole and an S-pole appear on the exposed surface of the core 301, respectively. appear. Therefore, the same operation and effect as those of the first embodiment can be obtained.

In the present embodiment, the field coils 30a,
Although an example in which two 30b are used has been described, the same operation and effect as in the second embodiment can be obtained by using one field coil.

(Fourth Embodiment) In each of the above embodiments, an example in which a permanent magnet or a field coil is rotated has been described. However, as in the fourth embodiment shown in FIG. 13, a large number of field coils are fixed. Thus (without rotation), an electromotive force can be generated by supplying a magnetic field to each portion of the stator coil at a position facing the field coil.

In FIG. 13, a large number of field coils 30 each formed by winding a coil around a core are fixedly attached to the pedestal portion 11 (see FIG. 1) of the insulation diagnostic device 1 and One by one for each lap winding part,
The stator coils 22 are arranged side by side in the circumferential direction. The current control device (current control means, excitation position detecting means) 40 controls the current flowing through each field coil 30 and the timing at which the current flows, and as shown in FIG. 14, the current controlled in a triangular waveform. Is sequentially passed through each field coil 30. Therefore, the same magnetic flux change as the temporal change of the magnetic flux received by the stator coil when the permanent magnet or the field coil is rotated can be given to the stator coil by controlling the current. Further, a position signal of the field coil through which current is flowing is sent from the current control device 40 to the judgment display 19.

According to the above configuration, since the magnetic flux changes in proportion to the current flowing through each field coil 30, the field coils 3
The magnetic flux can be changed over time by controlling the current flowing to zero, so that even if the field coil 30 is fixed, an electromotive force can be generated in the stator coil 22.

Then, as shown in FIG. 14, an electric current is sequentially passed through the field coil 30 to generate an electromotive force in the lap winding portion where the magnetic field is supplied, and the electromotive force is measured to obtain a stator coil. 22 can be detected. Further, since the electromotive force and the position of the field coil carrying the current are observed in association with each other on the determination indicator 19, the portion having the poor electrical insulation can be specified.

One field coil 30 may be provided for each linear portion of the segment conductor (a portion located in the slit), or an adjacent field coil 30 may be provided if it does not affect the output voltage of the same polarity and another phase. May be used also as the other-pole field coil 30.

Further, as described above, the large number of field coils 30
Current may be passed through each one of them sequentially, or two field coils 30 arranged at symmetrical positions separated by 180 ° in the circumferential direction, or a magnetic pole pitch separated by the same phase of the stator coil 22. The two field coils 30 at the positions may be paired, and a current may be sequentially passed to each of the paired field coils 30.

(Fifth Embodiment) In the first embodiment,
Although the presence / absence of electrical insulation failure is determined based on the Min value and the Max value of the electromotive force, the presence / absence of electrical insulation failure is determined based on the integrated value of the electromotive force as in the fifth embodiment shown in FIG. Can be.

In FIG. 15, the voltage waveform storage means 50 receives the magnet rotation position signal from the encoder 18 and the voltage waveform of the electromotive force measured by the measuring instrument 17. The voltage waveform storage means 50 stores a portion S indicated by hatching in FIG.
s, the portion S exceeding -Vs is integrated, and the integrated value and the magnet rotation position signal are stored together.

The integrated value is input to a comparator 51, which compares the integrated value with a set threshold value, and sends the result of the comparison to the judgment display 19. If the integrated value is smaller than the set threshold value, it is determined that the stator coil 22 is defective in electrical insulation, and the fact that there is defective electrical insulation and the location of the defective electrical insulation are displayed on the determination display 19. As described above, the accuracy of the determination of the presence or absence of the electrical insulation failure can be improved by comparing the values with the integral values.

When the inspection is performed with the field coil fixed as in the fourth embodiment, the position signal of the field coil carrying the current is stored in the voltage waveform storage instead of the magnet rotation position signal. What is necessary is just to input into the means 50.

(Sixth Embodiment) In the first embodiment, FIG.
The electromotive force was measured between the X-phase and Y-phase and between the Y-phase and the Z-phase of the stator coil 22 by the circuit shown in FIG. it can.

That is, if the neutral point 22N is welded and before the neutral point 22N is subjected to the insulation treatment, the neutral point 22N is grounded as in the sixth embodiment shown in FIG. The electromotive force can be measured for each phase by connecting the voltmeter 17b to the ends 22X, 22Y, 22Z on the anti-neutral point 22N side of the phase. The other configuration is the same as that of the first embodiment.

According to the present embodiment, when the X phase is rare in the phase,
5 and FIG. 6 are obtained when the X-phase and the stator core 21 are grounded, and when the X-phase and the other phases are rare, an output waveform as shown in the upper part of FIG. 9 is obtained. The same operation and effect as those of the first embodiment can be obtained.

In this embodiment, the example of measuring the X-phase electromotive force has been described. However, by connecting the voltmeter 17b to the ends 22Y and 22Z of the other phases, the Y-phase and Z-phase electromotive forces can be measured. Can be measured.

(Seventh Embodiment) In each of the above embodiments, Y
Although the example of the case of the connected stator coil 22 has been described,
Even for stator coils connected in a polygonal connection (for example, delta connection), insulation failure can be detected by measuring the electromotive force.

The seventh embodiment shown in FIG. 18 shows a method of measuring an electromotive force in the case of a stator coil in which only one phase coil is accommodated in one slot in a delta connection, and the X phase is measured. Is grounded, and a voltmeter 17b is connected to the other end of the X phase.

According to the present embodiment, an output waveform as shown in FIG. 4 is obtained in a normal state. At the time of the in-phase rare of the X phase as shown by the broken line A in FIG. 18, the electromotive force detected by the voltmeter 17b has a waveform as shown in FIG.
In the rare case of the X-phase and other phases as shown by the broken line B, an output waveform as shown in FIG. 20 is obtained for the electromotive force. When the X-phase and the stator core 21 are grounded as shown by the broken line C in FIG. As the power, an output waveform as shown in FIG. 21 is obtained.

(Other Embodiments) In the first embodiment, the magnets 13 arranged at positions 180 ° apart in the circumferential direction are used.
The directions of the magnetic poles a and 13b were reversed, and the winding direction of the stator coil 22 at a position 180 ° apart was the same. However, the positions of the two magnets 13a and 13b are not limited to positions 180 ° apart from each other. That is, if the magnets 13a and 13b having opposite magnetic poles are arranged at positions separated by a predetermined angle from each other, and the winding directions of the stator coils 22 at the positions separated by a predetermined angle are the same, the same operation and effect can be obtained. Is obtained.

The same applies when the directions of the magnetic poles of the magnets 13a and 13b arranged at positions spaced apart by a predetermined angle in the circumferential direction are the same, and the winding direction of the stator coil 22 at the position separated by a predetermined angle is reversed. The operation and effect of the invention can be obtained.
In other words, the stator coils 22 installed in the slots separated by a predetermined angle from each other,
When the magnetic field is changed by the magnets 3a and 13b, the magnets 1 are placed in such a positional relationship that electromotive forces cancel each other out.
What is necessary is just to arrange 3a, 13b.

In the above-described first to third embodiments, the measurement is made by a combination between two phases, that is, between the X phase and the Y phase, and between the Y phase and the Z phase. However, the measurement may be made by a combination between other two phases.

In the above-described first to fourth embodiments, the stator coil 22 is wrapped, but the present invention can be similarly applied to a wave-wound stator coil. Further, the present invention can be applied to a stator other than 36 slots, for example, a 72 slot stator.

In the first embodiment, the magnet rotating unit 12
A pair of magnets are arranged at positions 180 ° apart from each other in the circumferential direction with the magnetic poles reversed, but as in the third embodiment, both magnetic pole surfaces of the magnets are , The same operation and effect can be obtained with one magnet.

In the above embodiment, the stator 2 was modified by inserting an insulating member into a rare portion. However, it is also possible to repair the rare part by adding an insulating treatment by inserting a spatula or the like between the rare coils to provide a gap.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a stator inspection device of the present invention.

FIG. 2 is a schematic diagram showing an arrangement of magnets on an inner circumferential side of a stator in the insulation diagnosis device.

FIG. 3 is a circuit diagram of a stator coil in a measuring device.

FIG. 4 is a diagram showing an electromotive force measurement result when there is no rare in a stator coil.

FIG. 5 is a diagram showing an electromotive force measurement result when a stator coil has an in-phase rare.

FIG. 6 is a diagram showing an electromotive force measurement result when the stator coil is grounded.

FIG. 7 is a circuit diagram when a stator coil is grounded.

FIG. 8 is a diagram showing an electromotive force measurement result when there is an interphase rare in a stator coil.

FIG. 9 is a diagram showing an electromotive force measurement result when a stator coil has an interphase rare.

FIG. 10 is a diagram illustrating a state in which a magnet is moved inside a winding according to the second embodiment.

FIG. 11 is a diagram showing an electromotive force generated in the winding of FIG. 8;

FIG. 12 is a schematic diagram showing a configuration of a magnet rotating unit 12 in the inspection device of the third embodiment.

FIG. 13 is a schematic diagram showing an arrangement of field coils and the like in the inspection device of the fourth embodiment.

FIG. 14 is a diagram showing a current supply pattern for the field coil of FIG. 11;

FIG. 15 is a block diagram illustrating a configuration of an electrical insulation failure determination unit in the inspection device of the fifth embodiment.

FIG. 16 is a characteristic diagram of an electromotive force used for describing the operation of the fifth embodiment.

FIG. 17 is a circuit diagram of a measuring instrument in the inspection device according to the sixth embodiment.

FIG. 18 is a circuit diagram of a measuring instrument in the inspection device according to the seventh embodiment.

FIG. 19 is a view showing an electromotive force measurement result when a stator coil has an in-phase rare.

FIG. 20 is a diagram showing an electromotive force measurement result when a stator coil has an interphase rare.

FIG. 21 is a diagram showing an electromotive force measurement result when the stator coil is grounded.

[Explanation of symbols]

2 ... stator, 21 ... stator core, 22 ... stator coil, 13a, 13b ... permanent magnet constituting magnetic field supply means, 16 ... DC motor constituting magnetic field supply means, 30,
30a, 30b: field coils constituting magnetic field supply means,
40 ... Current control device constituting magnetic field supply means.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shoji Niwa 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. (72) Inventor Mitsuru Kato 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Takashi Tokizawa 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Inside Denso Corporation

Claims (30)

[Claims] 1. A method for inspecting a stator (2) in which a stator coil (22) is wound around a cylindrical stator core (21), wherein a magnetic field is supplied to the stator coil (22), and a magnetic flux is generated. Magnetic field supply means (13)
a, 13b, 16, 30, 30a, 30b, and 40) for detecting a portion to which a magnetic field is supplied by the magnetic field supply means, and for detecting a portion of the stator coil ( 22. A method for inspecting a stator, comprising: measuring an electromotive force generated in 22) to specify an insulation failure portion of the stator coil (22). 2. The magnetic field supply means includes a plurality of field coils (30) arranged in a circumferential direction of the stator coil (22) so as to face the stator coil (22). 2. The electromotive force generated for each of the stator coils (22) located at positions opposing the field coil (30) by controlling a current flowing for each (30). Stator inspection method. 3. The magnetic field supply means includes a field coil (30a, 30a) arranged opposite to the stator coil (22).
The stator inspection method according to claim 1, wherein 30b) is rotated along a circumferential direction of the stator (2) in an excited state to generate an electromotive force in the stator coil (22). 4. A permanent magnet (13a, 1a, 1b) disposed opposite to the stator coil (22).
The method according to claim 1, wherein 3b) is rotated along a circumferential direction of the stator (2) to generate an electromotive force in the stator coil (22). 5. A magnetic field is supplied to the stator coil (22) by the magnetic field supply means, an electromotive force generated in the stator coil (22) at a portion to which the magnetic field is supplied is measured, and a voltage of the electromotive force and The method for inspecting a stator according to any one of claims 1 to 4, wherein the method is compared with a reference voltage. 6. A magnetic field is supplied to one location in the circumferential direction of the stator coil (22) by the magnetic field supply means, and an electromotive force generated in the stator coil (22) at a location where the magnetic field is supplied is measured. And comparing a set value with an integral value of the time of the electromotive force.
In any one of the above, a stator inspection method. 7. A magnetic field is simultaneously supplied to two locations in the same phase of the stator coil (22) by the magnetic field supply means, and electromotive forces generated at two locations of the stator coil (22) cancel each other. Sometimes, it is determined that there is no insulation failure at two locations of the stator coil (22), and when detecting a difference in electromotive force generated at two locations of the stator coil (22), the stator coil (22) 7. The method for inspecting a stator according to any one of claims 1, 3, 4, 5, and 6, wherein it is specified that there are insulation failures at the two locations. 8. The direction of the magnetic pole in the core radial direction of the magnetic field supply means is opposite at each of two positions of the stator coil (22), and the winding directions of the two positions of the stator coil (22) are the same. The stator inspection method according to claim 7, wherein: 9. The direction of the magnetic pole in the core radial direction of the magnetic field supply means is the same at each of two positions of the stator coil (22).
The method for inspecting a stator according to claim 7, wherein the winding directions of the portions are opposite to each other. 10. The stator coil (22) is formed by connecting three-phase coils, and measures the electromotive force of each phase coil of the three-phase coils to insulate the stator coil (22). The method for inspecting a stator according to claim 1, wherein a defective portion is specified. 11. The stator coil (22) is formed by connecting three-phase coils in a Y-connection. The three-phase coils are paired in two-phase pairs to measure the electromotive force, and the stator coil (22) is formed. The method for inspecting a stator according to any one of claims 1 to 9, wherein the defective insulation position is specified. 12. The stator coil (22) is formed by connecting a multi-phase coil, and only one coil phase of the multi-phase coil is grounded on the anti-neutral side while the other coil is connected to another coil. An electromotive force measuring means (17) for measuring the electromotive force is connected to the anti-neutral side of the phase,
The method for inspecting a stator according to any one of claims 1 to 9, wherein the electromotive force is measured. 13. The stator coil (22) is formed by connecting multi-phase coils. The neutral point of the multi-phase coil is grounded. The method for inspecting a stator according to any one of claims 1 to 9, wherein the electromotive force is measured by connecting an electromotive force measuring means (17) for measuring an electromotive force. 14. The method for inspecting a stator according to claim 12, wherein the stator coil (22) is formed by connecting three-phase coils. 15. The stator inspection method according to claim 12, wherein a constant bias voltage is applied to a ground side circuit of the coil. 16. The stator coil (22) includes a plurality of partial windings (221a, 221b, 221c), and detects a partial electromotive force for each of the partial windings (221a, 221b, 221c). The method for inspecting a stator according to any one of claims 1 to 15, wherein an insulation state of the partial windings (221a, 221b, 221c) is detected based on the detected partial electromotive force. 17. The plurality of partial windings (221a, 221b, 221) constituting the stator coil (22)
c) sequentially supplying a magnetic field to the plurality of partial windings (221a, 221b, 221c)
17. The stator according to claim 16, wherein both end electromotive forces detected at both ends where the magnetic field is connected are detected, and both end electromotive forces detected corresponding to each of the magnetic field supply positions are set as the partial electromotive force. Inspection methods. 18. A method for inspecting a stator according to any one of claims 1 to 17, wherein a location of insulation failure of the stator coil (22) is specified, and insulation is applied to the location of insulation failure. A method for manufacturing a stator, which eliminates defects. 19. An inspection device for a stator (2) in which a stator coil (22) is wound around a cylindrical stator core (21), wherein a magnetic field is supplied to the stator coil (22) and the magnetic flux is timed. Magnetic field supply means (13)
a, 13b, 16, 30, 30, 30a, 30b, 40); and an excitation position detecting means (18, 40) for detecting a portion where the magnetic field supplying means supplies a magnetic field to the stator coil (22). And an electromotive force measuring means (17) for measuring an electromotive force generated in the stator coil (22). 20. The magnetic field supply means, comprising: a plurality of field coils arranged to face the stator coil; and a current control means for controlling a current flowing through each of the plurality of field coils. 20. The stator inspection device according to claim 19, comprising: (40). 21. The magnetic field supply means, comprising: a field coil (3);
20a, 30b) and turning means (16) for rotating the field coil in a circumferential direction of the stator (2) in an energized state. apparatus. 22. The magnetic field supply means includes a permanent magnet (13
20. The stator inspection device according to claim 19, comprising: a, 13b) and turning means (16) for rotating the permanent magnet along the circumferential direction of the stator (2). 23. A pair of field members (13a, 13a, 23a, 23b) for supplying a magnetic field to the stator coil (22). 13b, 30a, 30b) and turning means (16) for rotating the pair of field members along the circumferential direction of the stator (2). An inspection device for a stator according to any one of the preceding claims. 24. The pair of field members (13a, 13a)
b, 30a, 30b) are characterized in that the directions of the magnetic poles in the radial direction are opposite to each other, and the winding directions of the stator coils (22) facing the pair of field members are the same. The stator inspection apparatus according to claim 23, wherein 25. The pair of field members (13a, 13a)
b, 30a, 30b) have the same radial magnetic pole direction, and the winding directions of the stator coils (22) facing the pair of field members are opposite to each other. The stator inspection apparatus according to claim 23, wherein 26. One field member (13a, 3a, 3b) which is disposed opposite to the stator coil (22) and supplies a magnetic field to the stator coil (22).
20a) and turning means (16) for rotating the one field member along the circumferential direction of the stator (2).
The stator inspection apparatus according to any one of the above. 27. The stator inspection apparatus according to claim 19, further comprising comparison means (51) for comparing an integral value of the time of the electromotive force with a set value. . 28. Apparatus according to any one of claims 19 to 26, characterized in that comparison means (19) for comparing the voltage of the electromotive force with a reference voltage are provided. 29. A stator inspection device in which the stator coil (22) is formed by connecting three-phase coils, wherein the electromotive force measuring means (17) includes a coil for each phase of the three-phase coils. 29. The stator inspection apparatus according to claim 19, wherein the electromotive force is measured. 30. A stator inspection device in which the stator coil (22) is formed by connecting three-phase coils in a Y-connection, wherein the electromotive force measuring means (17) includes two different phases of the three-phase coils. 29. The stator inspection device according to claim 19, wherein the electromotive force is measured in pairs.