JPH0524738B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to an AC rotating electrical machine such as a turbine generator, and in particular to an AC rotating electrical machine such as a turbine generator, which is designed to avoid resonance with the vibration frequency caused by the magnetic field of the rotor. Regarding the stator frame.

(Prior Art) The stator core of this type of rotating electric machine is subjected to vibration force generated by the magnetic field of the rotor. especially 2 poles or 4 poles
A rotating electric machine having a rotating field type rotor with rotating poles has a problem with the resonance phenomenon of the stator. Therefore, it is necessary to set the natural frequency of the stator frame that supports the iron core away from the forced frequency to avoid resonance.

For example, in a two-pole 3600rpm turbine generator,
Since it has a forced vibration frequency of 120Hz, the natural frequency of the stator frame is set within the range of 60 to 85% of that frequency, that is, a low natural frequency to avoid resonance and suppress the increase in the diameter of the stator frame. There is.

As a conventional example of a stator frame with a low natural frequency, as seen in Japanese Utility Model Publication No. 52-30483,
There is one in which pads are spaced apart in the circumferential direction on the inner periphery of an annular main plate that supports the iron core, and cutouts are provided on the inner and outer peripheries.

In another conventional example, a plurality of holes are provided in the annular main plate in the axial direction, and a desired natural frequency can be generated by adjusting the opening area of the holes.

(Problems to be Solved by the Invention) These low natural frequency stator frames are effective when the main part of the stator frame is composed of an annular main plate and a side plate welded to the outer periphery of the stator frame. . However, a completely enclosed internally cooled rotating electric machine in which a storage box for a cooler or a terminal box protrudes from a side plate and has an airtight structure has problems that cannot be solved by the above-mentioned conventional techniques. That is, the box portion has a side wall plate extending perpendicularly to the rotational axis of the electric machine, and this side wall plate has a high-order natural frequency with respect to the direction of the vibration force. It is impossible to provide perforations or notches as in the prior art in order to lower the natural frequency in a totally enclosed internally cooled stator, and it is necessary to provide these holes and close them with a material with low rigidity. This should especially be avoided in the case of rotating electric machines that use hydrogen gas as a refrigerant.

Furthermore, regarding the stiffness that affects the natural frequency, it is necessary to consider the stiffness that affects the mode of vibration.
For example, when considering a two-pole machine in which the natural frequency of the entire stator frame is a problem among rotating electric machines, the vibration mode of the rotor's forced vibration with respect to the stator frame has an elliptical shape, and the completely enclosed cooling rotation Even in structures such as electric machines where a cooler, storage box, or terminal box is provided outside the stator frame and protrudes from the side plate of the stator frame, the same elliptical shape is exhibited. The vibration mode of the box-shaped side wall plate based on forced vibration exhibits a bending vibration mode in a plane perpendicular to the rotation axis, and the box-shaped side wall plate protruding outward from the stator side plate is perpendicular to the rotation axis. In a rotating electric machine having a portion parallel to a plane, the bending vibration mode coincides with the surface of the side wall plate in a plane perpendicular to the axis of rotation. In other words, the side wall plate is bent in-plane, and between the in-plane deformation and out-of-plane deformation of the side wall plate, the in-plane deformation inevitably has greater rigidity against the vibration mode, and when the rigidity against this vibration mode increases, the box-shaped Compared to the vibration mode of the stator frame when there is no part attached, the vibration mode on the rotation axis of the stator frame side plate changes in the part with the side wall plate, and this change is the natural vibration of the entire stator frame. It becomes a factor that changes the number.

The present invention has been made in view of the above points, and its purpose is to lower the forced frequency of the eigencore core without increasing the size of the integrally and airtightly protruding box-shaped portion. The purpose of the present invention is to provide a stator frame for a rotating electric machine.

[Structure of the invention]

(Means for Solving the Problems) The present invention supports a stator core via an elastic support device on the inner peripheral side of an annular main plate spaced apart in the axial direction,
This is an improvement to a fully enclosed stator frame which has a side plate fixed to and wrapped around the outer periphery of the main plate, and has a box-shaped portion fixed to the side plate and protruding to the outside of the side plate.

The present invention is characterized in that the side wall plate of the box-shaped portion has a portion that is not parallel to a plane perpendicular to the axis of rotation.

(Function) In the device configured in this way, the side wall plate of the box-shaped portion has a non-parallel portion with respect to the plane orthogonal to the rotational axis of the electric machine, so that it is not parallel to the plane perpendicular to the rotational axis of the electric machine. , the rigidity against the bending vibration mode in the plane perpendicular to the rotation axis is smaller than that of a part having a parallel part to the plane perpendicular to the rotation axis, and the natural vibration frequency is lower than the forced vibration frequency. becomes possible,
It is possible to eliminate the influence of the box-shaped portion on the natural frequency of the entire stator frame.

(Example) The present invention will be described in detail below based on the example shown in the drawings. 1 and 2 show a stator of a turbine generator showing one embodiment of the present invention. FIG. 1 shows the stator as seen from above, and FIG. 2 shows the stator as seen in the axial direction, with the main parts partially cut away. The stator frame 1 is a completely enclosed type that houses a cooler for cooling a refrigerant such as hydrogen gas or air to be sealed. Its structure includes a plurality of annular main plates 3 that support a stator core 2 around which a stator coil (not shown) is wound, and are arranged at appropriate intervals in the axial direction, and side plates 4 are arranged around the outer periphery of the annular main plates 3 to support a stator core 2 around which a stator coil (not shown) is wound. A reinforcing ring 5 is welded to the inner periphery so as to cover it. The annular main plate 3 has a large number of axially penetrating holes 3a through which cooling gas flows, and these holes serve to make the annular main plate 3 have a low natural frequency. The stator core 2 is supported by the reinforcing ring 5 via an elastic support device 6 . This device 6 consists of a number of horizontal spring bars 7 and key bars 8 that are engaged with an iron core and are fastened with bolts.

A cooler 10 is installed in the coolant flow path of the stator frame 1 . Frame 1 for storing this cooler 10
A box-shaped portion 9 that protrudes to the outside is provided in a part of the housing. This box-shaped portion 9 has a side wall plate 9a that closes its axial direction, and this side wall plate 9a forms a predetermined angle (θ) outward in the axial direction with respect to a plane perpendicular to the rotational axis O of the electric machine. It is also sloped. The axial mounting device for the side wall plate 9a is desirably mounted so as to be offset in the axial direction so as not to coincide with or intersect with the radially extending surface of the annular main plate 3.

Another embodiment shown in FIG. 3 shows a terminal box connecting the stator windings and the external busbar. In this terminal box, the base of the side wall plate 9b with the side plate 4 is parallel to facilitate welding work, and as it goes outward, it is inclined at a predetermined angle (θ) in the axial direction with respect to the plane perpendicular to the rotation axis O. I'm letting you do it.

FIG. 4 shows still another embodiment of the present invention. In this embodiment, the side wall plate 9c is bent into a dogleg shape. Also, Fig. 5 shows the side wall plate 9.
d is formed into an arc shape.

〔Effect of the invention〕

As explained above, the present invention supports a stator core on the inner circumferential side of an annular main plate spaced apart in the axial direction via an elastic support device, and fixes and covers the outer circumference of the main plate with a side plate. In the fully enclosed stator frame having a box-shaped part fixed to the side plate and protruding outside the side plate, the side wall plate of the box-shaped part has a non-parallel part with respect to a plane perpendicular to the axis of rotation. , it is possible to obtain a natural vibration frequency lower than the excitation frequency without increasing the size of the box-shaped portion.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a main part of a stator seen from above showing one implementation side of the present invention, FIG. 2 is a partial sectional view of the stator of FIG. 1 seen from the front, and FIG. 2 is a cross-sectional view of the terminal box section taken along the line - in FIG. 2 and viewed in the direction of the arrow, and FIGS. 4 and 5 are cross-sectional views of the stator frame showing other embodiments of the present invention, respectively. . 1 ... Stator frame, 2... Stator core, 3... Annular main plate, 4... Side plate, 9... Box-shaped part, 9a, 9
b, 9c, 9d... side wall plates.

Claims (1)

[Claims] 1. A stator core is supported via an elastic support device on the inner circumferential side of an annular main plate spaced apart in the axial direction, and a side plate is fixed to and wrapped around the outer periphery of the main plate, and the side plate is fixed to the side plate and the outer side of the side plate is fixed to the outer circumference of the main plate. 1. A stator frame for a rotating electric machine, wherein a side wall plate of the box-shaped part has a non-parallel part with respect to a plane perpendicular to the axis of rotation, in the completely enclosed stator frame having a box-shaped part projecting from the side.