JPH0767250B2 - Field winding interlayer insulation for rotating electrical machines - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to field winding interlayer insulation of a rotating electric machine such as a rotor winding of a turbine generator, and more particularly to a structure for preventing displacement thereof.

[Conventional technology]

FIG. 4 is a fragmentary sectional view showing a general field winding structure of a turbine generator, and the field coil 1 (also called a rotor coil) includes a plurality of coil conductors 2 made of a flat copper band. One turn of coil conductor 2 and one layer of interlayer insulation are alternately inserted while the inner wall surface of the groove (slot) 5A formed in the flat-wound coil of the turn and formed in the rotor core 5 is covered with the ground insulation 6. Then, finally, the insulation 8 under the wedge is inserted, and the wedge 7 is further pushed in to fix it to the rotor core. Further, a coil holding ring and an end ring (not shown) are fitted on the outer peripheral side of the coil end of the field coil 1 to transmit and support the centrifugal force acting on the coil end to the coil holding tube.

By the way, as described above, the field coil 1 housed in the rotor core 5 is displaced between layers of the coil conductor 2 due to the bending of the rotor shaft during operation, and the temperature change between start and stop is caused between turns. The difference between the coil conductors also causes a displacement between the layers, and further, a swelling due to the centrifugal force at the coil end and a displacement at the time of stop cause a displacement between the layers, resulting in a complicated displacement between the coil conductors. Further, if these movements are restrained, stress is generated in the conductor and the rotor shaft, causing vibration and fatigue. Therefore, in order to prevent the interlayer insulation from being displaced from the coil conductor, only one surface 8 of the interlayer insulation 3 is bonded to the coil conductor as shown in FIG. 5 which is a sectional view of the main part of the coil end portion. The displacement is prevented, and the contact surface between the other surface and the coil conductor is used as the sliding surface 9 to prevent the generation of stress. On the other hand, the interlayer insulation 3 is mainly composed of a glass cloth as a base material, and is composed of a thin epoxy glass plate or a polyester glass plate which is heat-pressed after being coated and impregnated with a synthetic resin such as an epoxy resin or a polyester resin. Since the belt-shaped members or the belt-shaped members which are curved in the width direction are combined to form a loop shape, as shown in FIG. The part 4 is formed.

[Problems to be Solved by the Invention]

In the interlayer insulating structure configured as described above, since the sliding surface 9 is composed of the synthetic resin plate of the glass base material and the coil conductor, both are worn by friction when the coil conductors are displaced from each other. When copper powder is generated due to abrasion, the end surface of the interlayer insulation 3 having no protruding portion 3A is bridged by the copper powder in the slot, and an interlayer short-circuit current flows, and the heat damages the interlayer insulation 3 and the ground insulation 6. Ground fault current flows,
There is a risk of developing into a major accident, such as melting of the exciting coil and iron core. Further, the positional deviation of the coil conductor in the slot 5A in the axial direction of the rotor is converted into the positional deviation in the width W direction of the coil conductor at the coil end portion in the direction orthogonal to this, as shown in FIG. Therefore, in the coil end portion, the protruding portion 3A is formed by making the width of the interlayer insulation 3 larger than the width W of the coil conductor. However, since the creepage distance of the protruding portion 3A becomes short due to the positional deviation, this portion is also formed. There is a risk of short circuit between layers. Furthermore, interlayer insulation 3
There is also the uneconomical effect of increasing the number of man-hours required for connecting diagonally.

An object of the present invention is to obtain an interlayer insulating structure capable of preventing restraint of the coil without generating copper powder even if the coil conductors are displaced from each other.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, according to the present invention, a field coil formed of a plurality of turns and housed in a groove of a rotor core and each turn of a coil end portion of the field coil outside the groove of the rotor core are provided. In the interphase insulation to be interposed, the interphase insulation is made of two layers of interphase insulation material, one surface of each is bonded to the coil conductor, and the two surfaces of interphase insulation material form a sliding surface. In addition, the joints in the longitudinal direction of the two-layer interphase insulating material are butt-shifted with respect to each other in the longitudinal direction, and the width of the two-layer interphase insulating material in the coil end portion is larger than the coil conductor width. It is assumed that the protruding portions protruding from both ends of the conductor are formed.

[Action]

In the above means, two layers of the interlayer insulating material are used, and one surface of each layer is bonded to the coil conductor, so that the layer of the two layers of the interlayer insulating material becomes a sliding surface, so that abrasion powder is generated. Also produces only insulating dust, so short-circuit accidents can be avoided almost completely. In addition, when the coil conductor is displaced in the width direction at the coil end portion, 2
Since the inter-layer insulating material of the sheet shifts in the opposite directions together with the coil conductor and the creepage distance increases, a short circuit accident in this portion can be almost completely avoided. Furthermore, the seams of the two interphase insulating materials are offset from each other and butt-joined, whereby the insulation at this portion is strengthened and the number of processing steps is greatly reduced.

〔Example〕

 The present invention will be described below based on examples.

FIG. 1 is a sectional view of an essential part of a coil end portion showing an embodiment of the present invention. An interlayer insulation 13 interposed between coil conductors 2 is composed of two layers of interlayer insulation materials 13A and 13B. The surface in contact with the coil conductor 2 is fixed to the coil conductor 2 as an adhesive surface 8 with an adhesive. Therefore, the contact surface between the interlayer insulating materials 13A and 13B serves as a sliding surface 19 for the coil conductor 2.
Mutual displacement causes mutual movement and releases the restraining force between the conductors. As the interlayer insulating material, the same material as the conventional one, which is thin, can be used, and it is preferable to select a material having a low friction coefficient with gloss on the sliding surface side or, if necessary, a low friction coefficient for the friction surface. It may be configured to interpose a sliding material such as a fluororesin film.

In the embodiment interlayer insulating structure thus configured,
Since the sliding surface 19 is made of insulating material, even if abrasion powder is generated, it is insulative dust.Therefore, interlayer short-circuiting of coil conductors does not occur due to this, and the binding force between coil conductors is reduced. Can be released.

FIG. 2 is a cross-sectional view showing a positional displacement state of the coil end portion in the embodiment structure, and two interlayer insulating materials 13A and 13B are displaced in opposite directions with the sliding surface 19 as a boundary, so that they are along the interlayer insulating surface. The creepage insulation distance between the coil conductors changes in an increasing direction. Therefore, the insulation performance does not deteriorate due to the positional displacement between the coil conductors, and high insulation reliability can be obtained.

FIG. 3 is a side sectional view showing a joint in the longitudinal direction of the interlayer insulation in the embodiment. Two interphase insulating materials 13A and 13B have butt joints 14A and 14B, and two butt joints are coils. By forming the conductors 2 at positions displaced from each other by a distance 1 in the longitudinal direction, the creepage distance between the coil conductors passing through the sliding surface can be arbitrarily set to be larger than that of the conventional diagonal joint portion 4, and high insulation reliability can be obtained. As well as
Since only a simple operation of abutting the edges of the materials is required, the processing man-hours and processing time are reduced or shortened.

〔The invention's effect〕

As described above, according to the present invention, the interlayer insulation is adhered to the coil conductors as the two interlayer insulation materials, the overlapping surface of the two interlayer insulations is used as the sliding surface, and the interlayer insulation materials are displaced in position and joined by butt joining. Configured to do so. As a result, the conventional problem that copper powder is generated due to the positional displacement between the coil conductors and the risk of interlayer short-circuiting is eliminated, and the mutual restraint of the conductors can be safely released without causing interlayer short-circuiting. The position shift of the end part rather acts on the safety side by extending the creepage insulation distance, and the creepage insulation distance of the joint part can be arbitrarily selected, and the insulation of a rotary electric machine with high insulation reliability against interlayer short circuit A magnetic winding can be provided. In addition, since the joining portion in the longitudinal direction of the interlayer insulating material has a simple structure in which the cut surfaces are butted against each other, there is an advantage that the processing man-hour and the processing time can be significantly reduced as compared with the conventional diagonal lap joining.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a coil end portion showing an embodiment of the present invention, FIG. 2 is a sectional view showing a positional deviation state of a coil end portion in the embodiment, and FIG. 3 is an interlayer insulating material in the embodiment. 4 is a side sectional view of a main portion showing a joint portion of FIG. 4, FIG. 4 is a partially fragmented sectional view showing a general structure of a field winding, and FIG. 5 is a sectional view showing a main portion of a coil end in a conventional structure. FIG. 6 is a cross-sectional view of an essential part showing a position shift of the coil end in the conventional structure, and FIG. 7 is a side view of the essential part showing a joint part of interlayer insulation in the conventional structure. 1 ... field coil, 2 ... coil conductor, 3, 13 ... interlayer insulation, 4
… Joined part, 5… Rotor core, 5A… Groove (slot), 6…
Ground insulation, 8 ... Adhesive surface, 9,19 ... Sliding surface, 13A, 13B ... Layered interlayer insulation, 14A, 14B ... Butt joint, l ...
Misalignment of joints, W ... Width of coil conductor.

Claims (1)

[Claims] 1. Interphase insulation interposed between each turn of a field coil consisting of a plurality of turns and housed in a groove of a rotor core and a coil end portion of the field coil outside the groove of the rotor core, The interphase insulation consists of two layers of interphase insulation material,
One side of each is bonded to the coil conductor,
The laminated surface of the two-phase interphase insulating material forms a sliding surface, and the longitudinal joints of the two-phase interphase insulating material have a butt structure that is displaced from each other in the longitudinal direction. A field winding interphase insulation of a rotary electric machine, characterized in that a width of the two-phase interphase insulating material is larger than a width of the coil conductor, and projecting portions projecting from both ends of the coil conductor are formed.