JPH0819200A - Stator coil for rotating electric machine and its replacement method - Google Patents

Abstract

PURPOSE:To obtain a stator coil, for a rotating electric machine, whose dismantling and restoring operation can be performed in the accident or the periodic inspection of the rotating electric machine without damaging an insulating coating by applying a mechanical stress to the stator coil and whose operability is excellent. CONSTITUTION:A stator coil 11, which is formed so as to invert and bundle a conductor to which an insulating coating 16 has been executed, for a rotating electric machine, is provided with the conductor used for the stator coil, with the insulating coating 16 which is executed to the surface of the conductor and with a cutoff part 15, for the stator coil 11, which is formed in a coil-end part 11B exposed from a stator core 12 when the stator coil 11 is housed in a slot 13. Consequently, a connection means by which a conductor 17 on the side of a coil slot part 11A housed in the slot which is cut off by the cutoff part 15 is connected again to a conductor on the side of the coil-end part 11B and an insulation means which insulates the conductors connected by the connection means are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator coil used in a rotary electric machine, and more particularly to a stator coil for a rotary electric machine having a two-layer winding multi-turn coil structure.

[0002]

2. Description of the Related Art In the case of a rotating electric machine used for a power plant, a coil used here is a coil structure in which a plurality of conductors each having an insulating coating are bundled to form a wire, and the wires are rearranged. take. This is to prevent the current from flowing unevenly with respect to the rotating shaft of the rotating electric machine due to the increase in the cross section of the coil conductor portion.

Further, even in the case of a coil, particularly when the stator coil is housed in the stator core, it is divided into a one-turn coil and a multi-turn coil depending on the way of connecting the ends of the stator core. For small and medium-capacity machines of rotating electrical machines, there are many design degrees of freedom and easy to manufacture, and a multi-turn coil structure with a hexagonal shape is often adopted. This is because it is possible to effectively perform electromagnetic induction and obtain the necessary electromotive force by orbiting the strands of the coil that make up the coil in the stator core in multiple (multiple) turns, so the size of the device can be reduced. Is. Also, from the viewpoint of insulation, the medium- and small-capacity machine has a relatively small breakdown voltage of the wire portion as compared with the large-capacity machine, so that stable power can be obtained. Here, the structure of a rotating electric machine stator coil that has been conventionally used is shown in FIG.
It will be described with reference to FIGS.

FIG. 10 is a front view of the stator core and the stator coil as seen from the inner peripheral surface side of the stator core of the rotating electric machine, and FIG. 11 is a view showing the stator coil housed in a stator slot provided in the stator core. It is a side view of a stator core and a stator coil seen from the iron core inner peripheral surface side showing a state. Stator coil 11 stator core
A coil slot portion 11A that is accommodated in the slot 13 when it is accommodated in the slot 13 provided in the 12, a coil end portion 11B that is exposed from the iron core end, and a coil loop that displaces the upper coil and the lower coil in the case of two-layer winding It can be divided into part 11C.
Also, on the surface of the coil 11, there is a slot part depending on the terminal voltage.
11A is provided with a low resistance corona-preventing insulating coating portion 16A, and a part of the end portion 11B is provided with a high resistance corona-preventing insulating coating portion 16B. Further, the coil 11 has a coil pitch, which is an opening of a predetermined coil, such as slot # 1 and slot # 6.
After the lower coil piece 11D is stored as a lower layer coil on the bottom side of one of the two slots 13, the wedge 14 side which holds the coil stored in the slot by fitting the lower coil piece 11D into the groove provided in the slot, that is, An upper coil piece 11E is arranged as an upper layer coil on the lower coil piece 11D. Here, the coil pitch is a coil interval used with respect to the magnetic pole interval of the stator, and by selecting this coil pitch, harmonics can be removed and the voltage waveform can be improved,
Further, shortening the coil end portion results in shortening the axial length of the rotating electric machine. Then, the coil end portion 11B is transposed from the upper layer to the lower layer at the turn portion 11C and has a hexagonal shape, and the upper and lower coil pieces 11D and 11E are fixed to the slots by the wedge 14, and then the coil pieces 11D and 11E are fixed. The conductors 17 are electromechanically connected and subjected to insulation treatment according to the terminal voltage to form a stator coil.

As described above, the upper coil piece 11E and the lower coil piece 11D of two different coils are housed in the same slot, and each slot is not arranged in parallel with the inner peripheral surface of the iron core, but rather in the rotary electric machine. Since the coil pieces are radially arranged around the rotation axis, it is physically impossible to extract only the coil piece 11F alone from the slot when extracting the arbitrary coil piece 11F. Therefore, as a means for extracting the coil piece 11F, the coil 11 is artificially deformed and the disassembling work is performed.

This situation will be described with reference to FIG. FIG. 12 is a plan view showing a state of disassembling and replacing work of the stator coil by so-called fried coil work, and after removing the wedge, remove the bind wire for fixing the adjacent coil end parts to each other,
The coil 11 is disassembled by forcibly applying a load. This is to prevent mechanical stress from being concentrated on the insulating coating applied to the coil piece 11F by attempting to extract only the specific coil piece 11F to be disassembled and replaced. If the coil piece to be removed is 11FF, first
A coil adjacent to the coil piece 11FF, for example, a coil group 11G for 3 to 4 times the number of coil pitches is preheated to enhance the flexibility of the insulating coating, and then the coil is extracted to the inner peripheral surface of the iron core. A leverage lever 23 is applied, and the lever 24 and the end portion of each coil of the coil group 11G to be moved are tied with a thread 24. Then, by gradually applying a load to the lever shaft 23 and pulling it toward the center of the rotating shaft, the upper coil of another adjacent coil overlapped with the lower coil piece 11D of the coil piece 11FF to be extracted at the coil end portion. Disassemble or float the piece 11E from the slot and pull out the coil piece 11FF from the slot.

Further, the insulating coating 16 of the coil 11 is an important part for transmitting and receiving high voltage, and the reliability of the insulating coating 16 directly influences the function of the rotating electric machine itself. In working, great care must be taken not to subject the insulating coating 16 to excessive and intensive mechanical stress.

[0008]

However, in such a frying coil work, the deeper the slots are, the closer the adjacent coils are to each other, and the larger the coil pitch is, the higher the difficulty of the frying coil work is. Become. Further, since it is a work that relies heavily on the skill and intuition of skilled workers, it is difficult to maintain stable work quality.

Further, since the work is performed by applying mechanical stress to the coil and deforming it, it is unavoidable that the coil has some influence on the coil, and it is established at the expense of reducing the insulation life of the coil 16. However, it is basically not preferable for the insulation coating. In particular, when the remaining life of the insulation coating is small and the mechanical stress applied by the frying coil work is unacceptable, there is a problem that the remaining life cannot be utilized because there is no means for extracting.

Therefore, an object of the present invention is to enable the rotor coil to be disassembled and restored by an accident or periodic inspection without applying mechanical stress to the stator coil, and which has excellent workability. To get the stator coil of.

[0011]

In a stator coil of a rotating electric machine according to the present invention, a conductor used for the stator coil, an insulating coating applied to the surface of the conductor, and a conductor provided with the insulating coating are transposed. A stator coil that is bundled together with the stator coil, a stator coil disconnection portion selected at the coil end portion exposed from the stator core when the stator coil is stored in the stator core slot of the rotating electric machine, and the separation portion. A connecting means for reconnecting the conductor on the side of the coil slot and the conductor on the side of the coil end, which are accommodated in the slot separated by, and an insulating means for insulating the conductor connected by this connecting means. And

Further, according to the method of exchanging the stator coil of the rotating electric machine of the present invention, the surface of the conductor is provided with an insulating coating and is transposed, and the stator coil formed by bundling the conductor is placed in the slot of the stator core of the rotating electric machine. When cutting, cut off the detached part of the coil end exposed from the stator core, replace the stator coil cut at this detached part with a new stator coil, and put it in the slot separated by the detached part It is characterized in that the conductor on the coil slot side of the new stator coil and the conductor on the cut coil end side are reconnected by the connecting means, and the conductor connected by this connecting means is insulated by the insulating means. Method for replacing stator coil of rotating electric machine.

[0013]

With the configuration of the present invention, when the rotating electric machine is damaged or the stator coil is disassembled and repaired by periodical inspection, the stator coil is disconnected at the disconnecting portion selected as the coil end portion of the stator coil. By doing so, it is possible to extract coil pieces that need to be repaired and to relocate a new stator coil.Electrically and mechanically reconnect the conductor of the coil that has been relocated by the connecting means, and insulate between the conductor layers by the insulating means. It is possible to restore the conductor by covering and insulating the conductor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a stator coil showing a state of one stator coil that fits in a stator core. A stator coil 11 having a two-layer winding multi-turn coil structure is housed in a slot 13 provided in a stator core 12 of a rotary electric machine, and is a coil against electromagnetic external force generated by the operation of the rotary electric machine. A wedge 14 is provided for fixing the. And
A portion of the stator coil which is accommodated in the slot 13 provided in the stator core 12 is a coil slot portion 11A, and a portion which is exposed outside the stator core 12 is a coil end portion 11B.

Now, after the wedge 14 is pulled out from the slot, the binding wire fixing the coil end portion is removed, and the coil end is placed against the lower coil piece 11D of the coil piece 11FF which is to be taken out and replaced, which is stored in the upper side of the slot. In the portion 11B, the disconnecting portion 15 is selected at a position where the influence of corona discharge due to the operating electric field due to the operation of the rotating electric machine is small. For example, the insulating coating 16 applied to the coil slot portion 11A is connected to the insulating coating portion 16A subjected to the low resistance corona prevention treatment, and a position separated from the insulating coating portion 16B applied to the coil end portion 11B subjected to the high resistance corona discharge prevention treatment. Then, with the coil piece housed in the slot, the upper layer side of this coil piece 11FF is cut and separated with a cutter. Then, when viewed from the inner peripheral surface of the iron core, the coil piece
Since you can see the whole form of 11FF, this coil piece 11FF
It can be easily disassembled by pulling it toward you while looking at the balance.

Next, a method of restoring the disassembled stator coil will be described. The stator coil used in this embodiment has three turns, and each conductor 17 which is a current-carrying portion is composed of six flat copper wires which are insulated in two rows and three stages. As shown in Fig. 2, after removing the coil to be replaced, a new coil 11F 'with the same shape and both ends exposed from the iron core and having longer connection allowances is repositioned in the original slot and the wedge removed during disassembly. Fix at 14.

Next, as shown in FIG. 3, the connection margin is cut and arranged around the disconnecting portion, and the conductor 17 of the coil piece 11D, which is a coil to be continuously used, and a new coil 11F 'which is separated and replaced so as to face the conductor 17. The respective conductors are electrically and mechanically connected to each other. Since this coil has 3 turns, conductors in 2 rows and 3 stages
Details of the connection "A" for one row of conductors 17 are shown in FIG.

4 to 6 are partially enlarged views showing the procedure of the connecting means and the insulating means according to the embodiment of the present invention. In FIG. 4, a method of silver brazing, soldering or the like is applied to the superimposing section 17X for superposing the conductors 17 of the rectangular copper wire 19 in the first row on which the insulation coating 16B of the high-resistance corona discharge prevention processing section is removed to each other. To connect. Next, in FIG. 5, for example, an aramid paper matching the connection size of the rectangular conductor 17 is applied as the layer insulation 18 so as to overlap the adjacent insulating coating around the conductor 17 which is the current-carrying portion. By performing this layer insulation, the discharge resistance between the conductors is further improved. Further, in FIG. 6, the flat copper wires 19 in the second row do not overlap with the overlapping portion 17X in the first row on the layer insulation 18 in the first row, and they are close to each other, for example, the overlapping portion 17X. A superposition portion 18XX for superposing the conductors 17 on each other is provided at a position where a distance of about long strength is maintained, and the conductors are connected to each other to provide the layer insulation 18 in the second row.

Then, the flat conductors 17 in the third row do not overlap with the overlapping portions 18XX in the second row on the layer insulation 18 in the second row, and they are close to each other as in the first and second rows. conductor
The overlapping portion 18XXX for overlapping 17 is provided to perform connection, and the connection as one conductor 17 is completed. Similarly, the conductor 17 on the second and third turns is connected.

Next, as shown in FIG. 7, for each conductor 17,
Turn insulation 19 is applied by winding mica tape. Further, as shown in FIG. 8, by winding a mica tape having the same insulation performance as that applied before disassembling and replacing the coil on the outer circumference, the insulation between the conductors and the ground insulation are achieved. The insulation cover 16 is restored and the insulation process is completed.

Next, processing for preventing vibration of the coil end portion during operation of the rotating electric machine will be described with reference to FIGS. 8 and 9. A spacer 20 that is closely attached to the gap between the coil end portion 11B of the disassembled and exchanged coil piece 11FF and the end portion 11B 'of the adjacent coil that has not been disassembled and exchanged is inserted, and entangled with the support member 21 arranged on the outer periphery thereof. And bind it with the binding wire 22. The upper coil side is treated in the same manner. The spacer 20 has a rectangular polyester resin laminated plate 20A having a thickness thinner than the gap between coil ends as a core, and a cushioning polyester felt 22B impregnated with a room temperature curable epoxy resin is wrapped in a U shape. In this case, a solid support structure is obtained by integrating the coil end portions after the resin is cured.

It is possible to completely restore the work by performing the above-mentioned work on the other end of the disconnecting portion in the same manner. By adopting the above configuration, it becomes possible to disassemble and restore the stator coil without applying unnecessary mechanical stress to the insulating coating of the coil without performing the conventional frying coil work. . Further, since the range of the stator coil to be disassembled is only one coil pitch, the disassembly recovery workability is greatly improved and the construction period can be shortened.

[0023]

As described above, according to the stator coil of the rotating electric machine of the present invention, it is a coil end portion, and
A separation part is provided at a position relatively distant from the iron core, that is, the ground, where the surface electric field during operation is low and is not easily affected by corona discharge or the like, and only the coil that needs to be repaired and replaced is taken out from the separation part for restoration. Therefore, without impairing the remaining life of the insulation coating applied to the coil and the insulation coating,
Also, in order to remove one coil that needs repair and replacement, the number of moving coils or the range of disassembly of 20 coils, which was previously unavoidable and does not require adjacent disassembly and replacement, is 1/3.
It is possible to reduce it to 1/4, and the workability can be greatly improved and the construction period can be shortened.

[Brief description of drawings]

FIG. 1 is a side view of a stator coil of a rotary electric machine according to an embodiment of the present invention.

FIG. 2 is a side view of a stator coil of a rotating electric machine showing a detaching portion according to an embodiment of the present invention.

FIG. 3 is a side view of the stator coil of the rotating electric machine showing the connecting means according to the embodiment of the present invention.

FIG. 4 is a partially enlarged view showing the procedure of the connecting means according to the embodiment of the present invention.

FIG. 5 is a partially enlarged view showing the procedure of the connecting means according to the embodiment of the present invention.

FIG. 6 is a partially enlarged view showing the procedure of the connecting means according to the embodiment of the present invention.

FIG. 7 is an enlarged view of a stator coil end portion showing a connecting means according to an embodiment of the present invention.

FIG. 8 is an enlarged view of a stator coil end portion showing a connecting means according to an embodiment of the present invention.

FIG. 9 is an enlarged view of a stator coil end portion showing a connecting means according to an embodiment of the present invention.

FIG. 10 is a conceptual diagram showing a connection state of a stator coil of a rotating electric machine.

FIG. 11 is a front view of the stator coil turn portion of the rotating electric machine as viewed from the rotation axis direction.

FIG. 12 is a conceptual diagram showing a conventional frying coil work.

[Explanation of symbols]

11 ... Stator coil, 11A ... Coil slot part, 11B ... Coil end part, 12 ... Stator core, 13 ... Slot, 14 ...
Wedge, 15 ... Separation part, 16 ... Insulation coating, 17 ... Conductor, 18 ... Layer insulation, 19 ... Turn insulation, 20 ... Spacer, 21 ... Support member, 22 ... Bind wire, 23 ... Lever, 24 ... Thread.

Claims (2)

[Claims] 1. A conductor used for a stator coil, an insulating coating applied to the surface of the conductor, a stator coil formed by transposing and bundling the conductor coated with the insulating coating, and the stator coil. Detachment portion of the stator coil selected in the coil end portion exposed from the stator core when placed in the slot of the stator core of the rotating electric machine, and coil slot portion that fits in the slot separated by this detachment portion Of the rotating electric machine, further comprising: connecting means for reconnecting the conductor on the side of the coil and the conductor on the side of the coil end portion; and insulating means for insulating the conductor connected by the connecting means. coil. 2. When a stator coil formed by applying an insulating coating on the surface of a conductor and transposing the bundle and housing the stator coil in a slot of a stator core of a rotating electric machine, a coil end portion exposed from the stator core is provided. The detached portion is cut, the stator coil cut by this detached portion is replaced with a new stator coil, and the coil slot portion of the new stator coil that fits in the slot separated by the detached portion Of the rotating electric machine, wherein the conductor on the side of the coil and the conductor on the side of the cut coil end are reconnected by connecting means, and the conductor connected by this connecting means is insulated by insulating means. How to replace the coil.