JPS58133144A - Inspecting device for rotor - Google Patents

Abstract

PURPOSE:To detect precisely an interlayer bridge due to faulty insulation inside a slot, by making it possible to detect the interlayer bridge of the part of the slot generated in-casting aluminum or the like to a rotor core, by magnetic means. CONSTITUTION:Exciting coils 2a and 2b are wound round nearly U-shaped two probe magnetic cores 1a and 1b in the directions reverse to each other, and the exciting coil 2a is connected to a power source 3a generating an AC output of a prescribed current value, while the exciting coil 2b is connected to an AC power source 3b whose output current can be adjusted. Moreover, a coil 2c for detecting a current flowing through a rotor bar is wound around a probe magnetic core 1c, and the detection output thereof is given to the power source 3b, while the output of the power source 3b is adjusted so that said detection output turns zero. Then, a phase detection output corresponding to a phase difference is given from a phase difference detector 6 to a phase difference discriminator 7. Thereby the phase difference detection output is compared with a phase difference serving as a criterion of determination to determine the result of the inspection.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is applied to the casting of aluminum or the like into a rotor core of a rotating electric machine, etc., which is made of laminated electric iron plates:
The present invention relates to a rotor inspection system in which interlayer bridges in slot portions that occur can be detected in a crystal by magnetic means.

[Summary of the invention]

In general, the rotor core of a small-capacity rotating electric machine 1: is made of laminated electric iron plates with slots, and the slot partial sound is die-cast from a streetcar material such as aluminum, and one end of the rotor core 1: Manufactured by integrally molding the shorting ring.

This is called a squirrel cage rotor, but in this case,
If the slot portion of an electric gun is not sufficiently insulated, the slot portion may cause interlayer bridging due to the electric field material such as aluminum, resulting in a loss greater than expected compared to the original design value.

The cause of this is during die-casting processing of aluminum etc.
This is often caused by an increase in the amount of cracking due to the interlayer bridges in the electrical steel plates that occur. For this reason, it is very important to detect the presence or absence of interlayer bridges in the rotor core before assembling the rotating electric machine.

[Melting point of treacherous technology]

Conventionally, in order to detect the presence or absence of such a bridge between the core layers, a magnetic test was performed in combination with a stator core for testing, or a probe with a dual excitation coil and a magnetic flux detection coil was placed on the surface of the rotor core. However, in the former method, each rotor core is subjected to a magnetic test in combination with the stator core. In addition, the latter method has drawbacks such as poor measurement accuracy.

[Purpose of the invention]

The present invention has been developed in view of the above-mentioned circumstances, and its purpose is to enable easy and highly accurate detection of interlayer bridges due to poor insulation in the slots in which the rotor core conductors are disposed. It is an object of the present invention to provide a second rotor inspection device.

[Summary of the invention]

That is, in order to achieve the above-mentioned object, the present invention 6. The surface of a rotor core etc. made of Toden material - 2. One magnetic core has a magnetic flux detection coil, and 12 excitation coils are wound in opposite directions. At least one pair of U-shaped probe cores having a U-shaped probe core C and a similar probe core C are placed in parallel and are brought into contact with each other in such a manner that these probe cores straddle the slot, and one of the probe cores is The excitation coil C2 conducts a predetermined alternating current, and the other excitation coil 62 supplies an AC fM current whose output is IJA%i in accordance with the output of the detection coil so that the output of the detection coil is suppressed. This causes the two probe cores to generate magnetic fluxes that are opposite to each other and equal to each other, and this magnetic flux (2) causes the current generated in the conductor in the slot to be completely canceled by C1, and the core interlayer bridge is energized. The phase shift that occurs in the magnetic flux of the probe magnetic core due to the thin current excavation in response to the subsidence is detected by comparing the phase difference between the detection phase of the magnetic flux detection coil and the reference magnetic flux that serves as a comparison standard, and is known from this phase difference. This 4= is intended to easily and accurately detect interlayer bridges in the rotor core.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 1iiv.

FIG. 1 is a block diagram showing the configuration of a device for detecting interlayer bridges in the slot portion of a rotor core according to the present invention, and FIG.
The figure is a perspective view showing how the probe in the device of the present invention is brought into contact with the surface of the rotor core. In the rotor core slot portion of the rotor, the conductor is processed to form the conductor in the slot portion into a cage shape, or a par-shaped conductor is inserted into the slot portion and both ends are short-circuited with a short-circuit ring. This test is for inspecting interlayer bridges with the conductor.

Details will be explained below.

In Fig.
The excitation coils 1m and 42 are wound with the winding direction reversed to each other, and the excitation coil 1 is connected to a power source 11 that generates an AC output of a predetermined current value, and the excitation coil 2b is It is connected to an AC power source 3b that can adjust the output current. Further, the IC has the probe magnetic cores Ja, Jb
This probe magnetic core has the same shape as the IC.
A detection coil IC for detecting the torque flow when the rotor bar fli passes is wound around the 2C, and the detection output of this detection coil 2C is the same as the output current adjustable t#.
13b, and m'1 so that this detection output becomes a
l) lJb has a configuration in which the output IjM is adjusted. That is, the E sources 3m and 3b are power supply circuits that are supplied with power from, for example, a common AC power supply and convert it into a local current voltage value, the former being a fixed output type, and the latter being a variable type with a noise back circuit. -Reduction.

Further, a magnetic flux detection coil 4 is wound around the probe magnetic core 1142.

The rIO1 cutting power source 3m, lb is '41III' which generates alternating current fluctuations that are not in phase with each other at the same frequency.

These probe magnetic cores J! , 7b, JC and excitation coil 2
m, 2b, the detection coil 2C, and the magnetic flux detection coil 4 form a probe 5.

^41st three proof magnetic cores Ja in probe 6,
Jb and Jc are each cavity 81 +8 as shown in Fig. 112
They are arranged facing each other so that 1m8g are lined up.

6 is the phase shift of the output of the power supply 3- for internal sensing;
It has a reference waveform generation section such as a sine wave generator that generates sine waves in synchronization, and the output of the magnetic flux detection coil 4 of the probe 5 is compared with the output of this reference waveform generation section as a reference, and its phase MC: The phase difference detector 1.1 that generates a corresponding phase difference detection output is the output pipe input of this phase difference detector C, and displays a phase difference corresponding to the phase difference detection output, or displays a preset allowable value. This is a phase difference determination device that compares the phase difference detection output with a predetermined phase difference reference V&, determines whether or not the test is successful based on the comparison result, and issues instructions such as notifying this.

In addition, 20 in FIG. 2-2 is a cylindrical rotor core, and 21 is a cylindrical rotor core that is radially opened near the outer circumferential side of the rotor core 20 and is open in the outer circumferential direction of the rotor core 20. 22 is a conductor (hereinafter referred to as a rotor bar) provided in the slot portion 11 and is formed by casting aluminum or the like. Although not shown, short-circuiting rings are integrally formed on both end faces of the rotor core to short-circuit each other at the ends of the rotor pars 22 when the rotor pars 22 are formed.

Next-2 Two operations of this apparatus having the above configuration will be explained.

Vehicle #t is 7111! Rotor core 20 which is lv member
Q) Presence or absence of an advisory bridge due to a severe defect between the rotor core 20 and the tarpaulin 22 formed from one die cast in the slot portion 21 ≦ vII! In order to output jI, three approximately U-shaped probe cores la, 1b, 1b,
7c, each probe magnetic core Ja, Jb, Jc
The same υ in the slot portion 21) is brought into contact with the surface 1 of the rotor animal core 20 so as to straddle the rotor bar 22, and a magnetic circuit is formed at r81 with the rotor core 20.

And probe magnetic core Ja from wax @ 331, 3 b
, JL+ @magnetic coil Za, Zbl: Gives AC output V and is worth 1 l.

Rotor bars 2 are installed on both i-plane sides of the 1p11 trochanter core 20.
2 is provided with 42 short circuits @is so that the length t is T, and the electric ff
Since J l is two-tracked, probe magnetic core 1a1fb
, 1 cv, the rotor bar 22 forms an l-turn secondary short circuit for each of the probe magnetic cores Is, lb, and Ic, as shown in FIG.

FIG. 8 shows the surface portion of the rotor core 20 developed in a plan view to show its details.

As mentioned above, the probe magnetic core ls* constitutes the probe 5v.
lb* When applied to the surface of the rotor core 20 by straddling the Icv rotor bar ZZW, the probe magnetic core Ja
, Jb (2) respectively generate magnetic flux, and a magnetic circuit is formed between each of these probe magnetic cores 1m, Ib and the rotor core 20.

Now, place the tip of the probe magnetic core 1 m at the positions a and b in Figure 8, and the tip of the probe magnetic core Jb at positions C and d 1lii.
Also, if these probe cores JaeZbeJcV are arranged so that e and f at the tips of the probe core Jc are [1], the magnetic flux generated by the probe core Ja enters the rotor core 20 from the tip of the probe core Ja. , b exits from the probe core 1a≦2 and returns.

On the other hand, the magnetic flux generated in the probe magnetic core Jb is in the opposite direction to that in the case of 1 m because the excitation coil 2b of Jb is wound 4 times in the opposite direction to the excitation coil k 2 a of the probe magnetic core 1 m.
The magnetic flux enters the rotor core 2o from the probe magnetic core Ib at a portion C, exits from a portion d, and returns to the probe magnetic core Jbζ2.

Also, if we assume that the excitation coils 1m and 2b have the same number of turns, the magnetic flux generated by the probe magnetic core xb will also be
The amount of magnetic flux generated is the same as that of m, and only the direction of the magnetic flux is opposite.

In this way, the magnetic fluxes of the probe magnetic cores Ja and Jb surrounding the same rotor bar 22v have opposite directions and become the same magnetic flux, so the currents generated in the rotor bar due to these magnetic fluxes cancel each other out and do not exceed each other.

However, the rotor core is 2o and the probe core is 1m.

(bar current) may flow through the turbator 22.

This bar current has a probe magnetic core of 1m.

This causes a change in the magnetic flux of ib.

Therefore, in the device of the present invention, 1 cf of blue-tooth cores are provided to detect this.

That is, when this par current flows, magnetic flux flows through the magnetic circuit constituted by the probe magnetic core IG, so the detection coil 2
et: is that a magnetic flux voltage based on this current 6 is generated. This magnetic flux voltage is given to the power source 3b as the detection output of the detection coil 2C, and the voltage #3b controls the output voltage 151ft so as to make this detection output zero. Therefore, this′
The magnetic flux of the probe magnetic core 1b excited by the output 42 of the trace source Jb is m! 1, the magnetic fluxes in the magnetic circuits of the probe magnetic cores 1 m and Ib are balanced, and no bar current is generated. At this time, since the rotor core 20 is a laminated core, the lamination direction (the second direction is high magnetic resistance, so the probe core is 1 m long)
, Ib has almost no effect on the probe magnetic core 1c4, so this balance is classified as high precision - second grade.

On the other hand, slot $2 of the rotor core 20 which is the core to be measured
If a short circuit occurs between the probe core Jm and the tar bar 22 due to poor insulation, etc., the two probe magnetic cores Jm,
The same phenomenon occurs when a tertiary winding with stone wire is applied to Jb, and a probe magnetic core i is placed in this tertiary winding.
a.

Jb (2 magnetic flux 62 causes 4 eddy currents.

The separately mentioned tertiary winding also functions as a tertiary union for the probe Icl2, but the probe magnetic core 1a.

(Since the excitation coils 2m and 2b of b are wound in opposite directions, they cancel each other out except for the 6-curved bridge part of the tertiary winding, and the probe magnetic core
Ct two shadows lkt no moon.

[7 Ka・shi, this swirl 11! Due to the loss due to fil=, the magnetic flux 62 of the probe magnetic cores Ja and Jb has a phase shift compared to the phase I when this loss does not occur.

On the other hand, the phase difference detector 6C has a rule written therein, for example 4'ii, which synchronizes the phase of the AC output of the source 3.
A reference waveform source of the main wave with the same frequency as 3 m is provided, and this reference waveform has the same phase as the magnetic flux of the probe magnetic cores Ja and Jb when no eddy flow loss occurs. .

Therefore, the output of the magnetic flux detection coil 4 for detecting the magnetic flux at 1 mg of the probe magnetic core is applied to the phase difference detector 6 and compared with the reference waveform to detect the phase difference. can be known.

FIG. 4 shows the relationship between the short circuit resistance, that is, the contact resistance between the rotor bar 22 and the rotor core 10, and the magnetic flux phase difference of the probe.

As can be seen from this figure, as the degree of short circuit between the rotor bar 22 and the rotor core 20 (the degree of decrease in slot insulation) increases, the magnetic flux phase difference increases, and there is a significant difference in the phase difference depending on the presence or absence of a short circuit. Since there is a good correlation between the short circuit resistance and the magnetic flux phase difference, the slot part σ
- It is possible to determine the presence or absence of a vertical bridge and its degree based on the magnitude of the magnetic flux phase difference.

Therefore, in order to compare and detect this phase difference, this device inputs the outputs of the two magnetic flux detection coils 4 to a phase difference detector 65, and compares it with the reference waveform output from the reference waveform generator in the phase difference detector 6. A) Obtain a 7-phase Hinoki output that supports phase difference. This phase difference detection output is input from the phase difference detector 6 to the phase difference determiner 1, and in the phase difference determiner 7, the phase difference detection output (two corresponding phase call display v?' It is permissible depending on the relationship between the degree of bridging and the rotor's durability.
Based on the phase difference to be x, the power for detecting the phase difference is compared, and a pass/fail judgment for the test is made and this is notified.

This makes it possible to know whether or not there is an interlayer bridge in the slot portion to which the probe 4 is applied.

Moreover, in this device, the electric voltage VLV of the rotor par is detected by the probe magnetic core 1c, and when the mutual magnetic fluxes are not balanced due to an unbalanced contact state of the probe magnetic core 14Jb with the rotor core 20 or other delayed output, the detection output Since the output of the rod 3bv is adjusted and the magnetic flux generated by the probe magnetic core 1b is automatically adjusted and balanced, only the phase difference due to eddy current loss can be accurately measured, and the inspection accuracy is extremely high.

In this way, the interlayer bridge of the core can be inspected with high accuracy and ease by simply applying the probe 5 to the other slot portions and performing the excitation.

It should be noted that the present invention is not limited to the embodiments described above and shown in Drawing C2, but can be implemented with appropriate modifications within the scope of the gist.1 For example, the probe may be a pair of probe magnetic cores for excitation. Although the configuration used has been shown, it is also possible to use multiple pairs.Also, although this fiill describes a squirrel cage rotor in which conductors, that is, rotor pars, are formed in the slots from Guicast C2, it is possible to form a conductor in each slot. In the case of a rotor ζ that is fitted into the rotor and short-circuited by providing short-circuit rings at both ends of the rotor ζ, the interlayer bridges in the slots can be inspected in the same manner.

In addition, although we have explained the case where the reference waveform is completely synchronized with the power supply, the source of the phase shift is known, so even if the reference waveform is out of synchronization, it is the same as long as the relationship of the phase shift is maintained (: Inspection It can be modified and implemented as many times as possible.

In addition, the probe magnetic core JC mentioned above has a structure in which the ends of the pair of excitation probe magnetic cores 1a and 1b are arranged in two, but the average rotor current generated due to the imbalance of the magnetic flux of the pair of probe magnetic cores Hm and 1b is It is possible to arrange the probe magnetic cores Ja and jb (1 cf of nib loop magnetic cores) between these probe magnetic cores Ja and jb, and to adjust the position of this probe magnetic core IC (
You can also do it in two steps.

〔Effect of the invention〕

As described above, the present invention provides a rotor core surface of a rotor in which a conductor is disposed in each slot of the rotor core through an insulating layer, and a portion of these conductors are short-circuited with a short-circuit ring. Direction E
The rIyE body is connected with a conductor, and each has an exciting coil V*', while C2 is a magnetic flux detection coil V that detects one flux.
*The A-magnetic excitation coil consists of at least a pair of magnetic cores wound round in opposite directions, and a magnetic core wound with a detection coil arranged in parallel with this magnetic core and detecting the current flowing through the conductor straddled. A predetermined alternating current output was applied to one of the excitation coils of the probe, and the detection output was adjusted according to the detection output so that the detection output was eliminated. a power source that supplies an AC output to the other excitation coil of the probe for excitation, and a reference generator that generates a reference signal that serves as a phase comparison reference for the detection output of the magnetic flux detection coil, the detection output of the magnetic flux detection coil This reference signal is compared with the reference signal t: phase M'.A magnetic core having a detection coil is placed in contact with the surface of the portion of the rotor core to be inspected, across two conductors, and the excitation coil is 7 to form a magnetic path of magnetic flux directed in opposite directions between the pair of magnetic cores and the rotor core so as to cancel the current in the conductor caused by these magnetic fluxes. If an unbalance occurs in the magnetic flux of the pair of magnetic cores and two currents flow in the straddled conductor, the detection output of the detection coil for tortoise detection causes the excitation current for the other excitation coil to be In addition to automatically adjusting the oil to ensure a perfect balance,
Rotor core Il! If an insulation defect occurs due to an interlayer bridge with the conductor in the part to be inspected (i+), the conductor and rotor core 11M pass through this defective insulation part.
Q) Magnetic flux C passing through the magnetic path in the current carrying path; eddy electric oil is generated and flows, resulting in loss - 2. Therefore, a phase difference occurs in the magnetic flux of the probe. 1. The output of the magnetic flux detection coil of the probe is the reference signal V &
The phase difference was detected in comparison with Hayabusa, and the presence and degree of interlayer bridges in the 62 slots (Q), which was the target of the 1st generation inspection of the 1st generation rotor core, was measured from this phase difference 1. Therefore, the interlayer bridge can be measured without being influenced by the current flowing through the conductor V* in the testing area, and the phase difference is relatively close to the resistance value of the six-layer bridge. Because of the correlation, it is possible to know the presence or absence and degree of interlayer bridges with high accuracy.1. Inspection is easy because all you have to do is bring the probe into contact with the surface of the rotor core to be inspected, and even if the rotor shape is different for mass-produced models or made-to-order models, the shape of the contact part of the magnetic core can be changed. In addition, since the device of the present invention has a simple configuration, it is not only economically superior, but also prevents the occurrence of a pair of magnetic cores being oriented in opposite directions due to the contact situation of the probe to the rotor core. Even if an unbalance occurs in the magnetic flux, this is automatically adjusted and the phase difference V due to the eddy current loss due to the interlayer bridge of the iron core can be detected without causing any current V to flow through the conductor. Therefore, the inspection can be performed with high accuracy. It is possible to provide a rotor inspection device having excellent features such as:

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. Figure 2 shows how the probe is brought into contact with the rotor core.
Fig. 88 is a perspective view of the surface of the rotor core with the vicinity of the probe contact point in Fig. 2 opened by 1:1 in order to explain the present invention in detail, and Fig. 4 shows the approximate resistance obtained by experiment. The relationship between the magnetic flux phase difference and the magnetic flux phase difference is shown in a small T diagram. 1a, Ib, 1c = Probe magnetic core, js. 2b...! fiJ magnetic coil, 2C...detection coil,
3a. 3b... Power supply, 4... Magnetic flux detection coil, 6... Probe, 6... Phase difference detector, 7... Phase difference discriminator, 20... Rotor core, 11... slot, z2・
・Rotor par

Claims (1)

[Claims] A rotor core of a rotor is formed by disposing a conductor in each slot of the rotor core through an insulating layer, and short-circuiting each end of these conductors with a short-circuit ring. C is used by being in contact with adjacent parts of the C, each having an excitation coil, and one of which is equipped with a magnetic flux detection coil for detecting magnetic flux, and the excitation coil consists of at least a pair of coils wound in opposite directions. The magnetic core and the conductor which is arranged in parallel with these magnetic cores and straddles these pair of magnetic cores are connected to the surface of the rotor core (= when the magnetic core is in contact with the magnetic core and the magnetic core has one winding of 42 detection coils, and one of the probes The wJ magnetic coil 12 provides a predetermined excitation output, and the other excitation coil 12 provides an excitation output corresponding to the repercussion of the detection output so as to suppress the detection output of the detection coil; The detection output of the magnetic flux detection coil has a single generator which generates a reference signal that is a phase comparison standard for the detection output of the flux detection coil, and the detection output of the magnetic flux detection coil is compared with the reference signal to detect a phase difference. A rotor inspection device comprising: a phase difference detecting means; and a means for giving a corresponding instruction to the detected phase difference 4.