JP3106840B2 - Insertion method of iron core groove of all impregnated insulation coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inserting an unimpregnated coil into an iron core groove in an all-impregnated insulated rotary electric machine in which a non-impregnated coil is inserted into a core groove and then entirely impregnated with resin.

[0002]

2. Description of the Related Art In a high-impedance rotating electric machine of an all-impregnated insulation system, first, a mycate or a composite mycate is arranged on the outer periphery of a coil conductor.
A non-impregnated coil obtained by winding a main insulating tape such as a tape to a predetermined thickness and covering the outside with a semiconductive layer for preventing external corona is inserted into the core groove of the rotating electric machine, and then inserting the coil between the coils. After performing the connection work and taping work of the coil end part, etc., the whole is housed in a resin impregnation device, the thermosetting resin is vacuum impregnated, the liquid level is returned to atmospheric pressure, and pressure impregnation is performed. Finally, the insulation treatment is performed in a procedure of transferring the whole to a heat curing device and subjecting the impregnated resin to heat curing treatment. Also, the main insulating tape has a bending elastic force. When taped outside the coil conductor having a rectangular cross section, for example, a tension is applied within a range where the main insulating tape does not break. Even when the tape is taped, the main insulating tape layer has an uneven bulge which is thin at the corners of the coil conductor and thick at the plane portion due to the bending elasticity of the tape. For this reason,
It is difficult to accurately measure the thickness of the main insulating tape layer, and the finished dimensions in the width direction of the coil are measured in advance with the bulging of the main insulating tape layer suppressed, and the measured value is the width of the iron core groove. Find the number of taping times that are equivalent to the dimensions, and manufacture an unimpregnated coil based on the number of taping times.
The core groove insertion operation is performed by a method of pushing the obtained unimpregnated coil into the core groove.

[0003]

In the conventional method of inserting the iron core groove while the main insulating tape layer is in the expanded state, there is a variation in the finished dimension in the longitudinal direction of the coil, so that a portion having a large finished dimension is required. At the corners of the core groove, the outermost outer corona-preventing semiconductive layer is damaged and its function is locally lost, and in the small finished dimensions, the portion between the iron core groove and the outer corona-preventing semiconductive layer is small. The conductive contact between the external corona-preventing semiconductive layer and the iron core is incomplete, and the conductive contact is further imperfect due to resin impregnation and heat curing. For this reason,
During operation of the rotating electric machine, a partial discharge (also called corona discharge) occurs in the gap of the part where the conductive contact state is incomplete due to the principle of capacitance partial pressure, and the main insulation layer of the coil deteriorates by discharge. Occurs.

An object of the present invention is to provide a method of inserting a core groove of an all-impregnated insulated coil which can maintain a conductive contact state between an external corona preventing semiconductive layer and an iron core and prevent partial discharge.

[0005]

According to the present invention, a main insulating tape is provided on the outer periphery of a coil conductor.
A non-impregnated coil obtained by winding the coil to a predetermined thickness and covering the outside with a semiconductive layer for preventing external corona, and inserting the unimpregnated coil into the core groove of the rotating electric machine. The width of the main insulating tape layer is corrected by squeezing in the width direction of the main insulating tape layer. An unimpregnated coil shall be inserted into the core groove.

The apparent thickness of the main insulating tape layer is reduced to 65% or less of the thickness by a molding press to correct the thickness. The time range until the swelling of the main insulating layer returns to 80% of the apparent thickness of the main insulating tape layer is defined as the grooving period.

[0007]

In the present invention, first, the unimpregnated coil is clamped in the width direction of the iron core groove by a forming press to correct the bulge of the main insulating tape layer. The air inside is expelled to the outside and the thickness of the main insulating tape layer shrinks, and the tightening load applied to the main insulating tape layer is strong at the part where the apparent thickness is large.
By adding a weakly distributed portion in a portion having a small apparent thickness, an effect of equalizing the thickness of the main insulating tape layer can be obtained. Then, the unimpregnated coil is inserted into the core groove with a grooving period of time in which the bulge of the main insulating tape layer of the unimpregnated coil removed from the forming press does not exceed the width of the core groove. By the time the air expelled to the outside by the correction is sucked into the main insulating tape layer again by the bending elastic force (recovery of bending) of the main insulating tape and the bulge of the main insulating tape returns. Since a time margin of about 10 to 20 minutes can be provided, by inserting a non-impregnated coil into the core groove as a grooving period in which the bulge of the main insulating layer does not exceed the width of the core groove, external corona prevention The unimpregnated coil can be inserted into the core groove without damaging the layer, and the outer corona prevention layer contacts the inner wall surface of the core groove evenly by using the return of the bulge of the main insulating tape layer. Function .

Further, when the apparent thickness of the main insulating tape layer is reduced to 65% or less thereof by a molding press to correct the swelling, the swelling of the main insulating tape layer is almost eliminated. In addition, a function of maximizing the grooving period can be obtained. Further, the return of the bulge of the main insulating layer is caused by the main insulating layer.
If the grooving period is set to the time range until the apparent thickness of the tape layer reaches 80%, the grooving period is secured from several minutes to 10 minutes, and the grooving operation is performed on the main insulating tape layer. It can be done smoothly without damage, and after inserting the coil into the iron core groove, the outer corona preventing semiconductive layer is pressed against the inner wall surface of the iron core groove by using the return of the bulge of the main insulating tape layer. The function of maintaining the conductive contact state is obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 is a cross-sectional view schematically illustrating a procedure of a method of inserting a core groove of a fully impregnated insulated coil according to an embodiment of the present invention.
(a) is a cross-sectional view of an unimpregnated coil, (b) is a cross-sectional view showing a corrected state, and (C) is a cross-sectional view showing a core groove inserted state. FIG.
1A, a non-impregnated coil 1 has a coil conductor 2 having a rectangular cross section and a main insulation tape of a predetermined thickness wound around the outer periphery of the coil conductor 2 such as a mycate or an assembled mycate. It is composed of a tape layer 3 and a semiconductive layer 4 for external corona prevention covering the outside thereof. Due to the bending elastic force of the tape, the main insulating tape layer 3 has a nonuniform bulge which is thin at the corners of the coil conductor and thick at the flat part, and its apparent thickness t.
Is largest at the center of the long side surface of the coil conductor 2 shaped into a rectangle.

In the embodiment of the present invention, as shown in FIG. 1B, the long side of the coil conductor 2 is placed between parallel pressing plates of a shaping press 5 driven by hydraulic pressure, pneumatic pressure, spring pressure or the like. Unimpregnated coil 1 so that tightening load is applied to the side surface
And a tightening load is applied to correct the bulge of the main insulating tape layer 3. The unimpregnated coil 1 in which the bulge of the main insulating tape layer 3 was corrected was removed from the forming press 5, and the time range in which the bulge of the main insulating layer did not exceed the width of the iron core groove was defined as the grooving period. As shown in FIG. 3), for example, it is inserted into a core groove 7 formed in the stator core 6 of the rotating electric machine.

FIG. 2 is a characteristic diagram showing a change with time of the thickness of the main insulating tape layer 3 in the method of inserting the iron core groove of the all-impregnated insulated coil according to the embodiment of the present invention. The change in the thickness represented by the ratio with the apparent thickness t of the insulating tape layer 3 as 1 is shown on the horizontal axis, and the elapsed time of the operation is shown on the horizontal axis. In the figure, the unimpregnated coil 1 has its apparent thickness t compressed to 60% by straightening by a shaping press 5. When the hydraulic pressure of the shaping press 5 is released, for example, the main insulating tape layer 3 gradually recovers its swelling, but its recovery speed is slow, and it recovers to nearly 90% of the apparent thickness t and reaches 10% until it saturates. A recovery time of about 20 minutes is required. Also,
Since a time margin of about 5 to 10 minutes can be obtained for recovering the apparent thickness t to 80%, the unimpregnated coil 1 is used for the core groove 7 by using this time margin as the optimum core groove insertion period T. Can be inserted. That is, assuming that the width of the iron core groove 7 is W _S and the width of the unimpregnated coil 1 at the time of bulging correction is W _P , the number of times of taping of the main insulating tape layer 3 is such that the condition of W _P <W _{S is} satisfied. By setting in advance,
An advantage that the unimpregnated coil 1 can be inserted into the core groove 7 without damaging the outer corona prevention layer 4 of the main insulating tape layer 3 during the optimum core groove insertion period T is obtained. Also, after inserting the iron core groove,
By utilizing the return of the bulge of the main insulating tape layer, the outer corona prevention layer 4 can be uniformly pressed into contact with the inner wall surface of the iron core groove. There is an advantage that the electric contact state is not hindered, so that the occurrence of external corona can be prevented, the main insulation layer can be prevented from being deteriorated by discharge, and a rotating electric machine having a fully impregnated insulation coil having high insulation reliability can be provided. Can be

FIG. 3 shows the dielectric loss angle (tan δ) of the fully impregnated insulated coil obtained by applying the iron core groove inserting method according to the embodiment.
FIG. 4 is a voltage characteristic diagram, and FIG. 4 is a discharge characteristic-voltage characteristic diagram of the total impregnated insulated coil obtained by applying the iron core groove inserting method according to the embodiment. Is shown as a comparative example. As is clear from the figure,
The voltage dependence becomes stronger due to the occurrence of corona discharge tan δ
The values are clearly lower in the level of the example curve than in the comparative example curve. In addition, the discharge charge amount (maximum value) indicating the discharge intensity reaches a level exceeding the measurement range in the high voltage region in the comparative example curve, but stays at a much lower level in the example curve. . From these results, the method of inserting the iron core groove of the fully impregnated insulated coil according to the embodiment of the present invention keeps the conductive contact state between the iron core and the semiconductive layer for preventing external corona in good condition, and suppresses the occurrence of external corona discharge. It turns out that it is excellent in function.

[0013]

As described above, according to the present invention, the unimpregnated coil is sandwiched by the forming press in the width direction of the iron core groove to correct the bulge of the main insulating tape layer, and after removing from the forming press the main insulating layer. The method of inserting the core groove of the fully impregnated insulated coil was configured such that the unimpregnated coil was inserted into the core groove, with the time range in which the bulge return did not exceed the width of the core groove as the grooving period. As a result, the core groove insertion work can be performed without damaging the outer corona prevention layer, which is the outermost layer of the main insulating tape layer, by correcting the bulge, and the outer corona prevention layer is formed by utilizing the recovery of the bulge after insertion. Can maintain a good conductive contact state by pressing against the inner wall surface, greatly reducing the occurrence of external corona discharge caused by damage to the external corona prevention layer and instability of the contact state with the iron core, which were problems in the past. Thus, it is possible to provide a rotating electric machine including a fully impregnated insulating coil having high insulation reliability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating a procedure of a method of inserting a core groove of an all-impregnated insulated coil according to an embodiment of the present invention;
(a) is a cross-sectional view of an unimpregnated coil, (b) is a cross-sectional view showing a straightened state, and (C) is a cross-sectional view showing a core groove inserted state.

FIG. 2 is a characteristic diagram showing a change with time of the thickness of a main insulating tape layer in the method of inserting an iron core groove into a fully impregnated insulating coil according to an embodiment of the present invention.

FIG. 3 is a graph showing a dielectric loss angle (tan δ) -voltage characteristic diagram of a fully impregnated insulated coil obtained by applying the core groove insertion method according to the embodiment.

FIG. 4 is a discharge charge-voltage characteristic diagram of a fully impregnated insulating coil obtained by applying the core groove insertion method according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unimpregnated coil 2 Coil conductor 3 Main insulation tape layer 4 Semi-conductive layer for external corona prevention 5 Shaping press 6 Iron core 7 Iron core groove t Apparent thickness T Optimum iron core groove insertion period

Claims (3)

(57) [Claims] A non-impregnated coil obtained by winding a main insulating tape to a predetermined thickness around the outer periphery of a coil conductor and covering the outside thereof with a semiconductive layer for preventing external corona, is inserted into a core groove of a rotating electric machine. A method of inserting, wherein the unimpregnated coil is sandwiched by a forming press in the width direction of the iron core groove to correct the swelling of the main insulating tape layer, and after removing from the forming press, the swelling of the main insulating layer is returned. A method of inserting a core groove of an all-impregnated insulated coil, wherein the non-impregnated coil is inserted into the core groove with a time range not exceeding the width of the core groove as a grooving period. 2. The method of claim 1, wherein the apparent thickness of the main insulating tape layer is reduced to 65% or less by a forming press to correct the core thickness. 3. The grooving period according to claim 1, wherein the time period until the bulge of the main insulating layer returns to 80% of the apparent thickness of the main insulating tape layer is set as the grooving period. Insertion method of core groove of insulation coil.