JPS635982B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stator of a rotating electrical machine such as a turbine generator, and particularly to a magnetic shielding device at the end of the core thereof.

In the stator of a large-capacity rotating electrical machine with a small number of poles, such as a turbine generator, eddy current flows at the end of the stator due to stray magnetic flux that enters in the axial direction from the end of the armature winding, causing the end of the iron core to There is a risk of local overheating or increased loss.

Therefore, in the past, an end plate shield was provided to prevent the stray magnetic flux from entering. This conventional structure is the first
It is shown in Figs.

In these figures, a stator 1 mainly includes a laminated stator core 2 having a ventilation duct 3, an armature winding wound within a slot of this stator core 2,
In other words, it is composed of a stator winding 4, an end plate 5 having fingers 6 arranged on both end faces of the stator core 2, and an end plate 7 for tightening these. An end plate shield 8 is provided to prevent the intrusion of stray magnetic flux from the ends of the coils 4. Further, as shown in FIG.
Of the fingers 6, the end duct finger 6a extends in the radial direction from the core back portion 5c to the teeth portion 5b, and the core back finger 6b extends in the radial direction in the core back portion 5c.

However, in such a conventional structure, stray magnetic flux entering the core end from the axial direction can be prevented by the end plate shield 8 at the core back section, but cannot be blocked at the teeth section. , the invading stray magnetic flux causes eddy currents to flow, causing local overheating. Various methods have been proposed to counter this problem, such as creating slits in the teeth section at the end of the core to make it difficult for eddy current to flow, but all of these methods involve shielding the stray magnetic flux itself that enters the teeth section. Therefore, sufficient effects could not be expected.

The present invention has been made in view of this point, and its purpose is to effectively shield the stray magnetic flux itself that invades the teeth portion of the iron core end, and to reduce local overheating and loss in a rotating electrical machine. Our goal is to provide a stator for this purpose.

To achieve this objective, the present invention utilizes existing end duct fingers by connecting the ends of a plurality of fingers extending radially from the core back part to the teeth part with a connecting conductor. A current path is formed in this portion, and an eddy current is passed through the current path to shield invading stray magnetic flux.

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

This embodiment differs from the conventional example shown in FIGS. 1 to 3 in the end abutment plate portion having fingers. Since the other parts are exactly the same as those of the above conventional example, illustration and explanation thereof will be omitted. That is, in this embodiment, each end duct finger 6a and core back finger 6b provided on the end abutting plate 5 are electrically connected to adjacent ones at both ends thereof by the connecting conductor 9, As a result, a current path is formed over a large area over the entire circumference of the core end. It is desirable that the connecting conductor 9 has a high bending and compressive strength, and a resistivity as low as possible, such as a cylindrical conductor. This connecting conductor 9 is connected to each finger 6a,
It is connected to the circumferential side surface of 6b by welding, brazing, etc., but at this time, it is connected at a position as far away from the end contact plate 5 as possible, that is, at a position offset to the outside in the axial direction,
Further, the connecting conductor 9 connecting the inner ends of the two end duct fingers 6a is connected at a position as close to the inside as possible.

According to this embodiment, a large eddy current equivalent to the number of poles can flow through the current path formed in a large area over the entire circumference of the core end including the teeth portion, so that eddy currents as large as the number of poles can flow. Stray magnetic flux can be effectively shielded by this eddy current. Moreover, since the current path through which this eddy current flows is exposed to the cooling gas flow path, it is well cooled, and since it is formed at a position as far away from the end abutment plate 5 as possible, the current flow is shunted to the end abutment plate 5. It is possible to reduce the eddy current caused by the current path and avoid the thermal influence from the current path.

In the above embodiment, all the fingers located around the entire circumference of the iron core end are connected by the connecting conductor, but it is not necessary to do so, and at least two end duct fingers located at the same tooth part are connected. Connect both ends of with a connecting conductor,
A current path through which eddy current flows may be formed in the teeth portion.

As explained above, according to the present invention, both ends of a plurality of end duct fingers located in the same teeth part are electrically connected by a connecting conductor, thereby causing an eddy current to flow in the teeth part. By forming a passage, it is possible to effectively shield stray magnetic flux that enters the teeth part, and since this current passage is exposed to the cooling gas flow path, even if eddy current flows and heats up, it can be effectively shielded. Cools extremely well. As a result, local overheating and loss at the ends of the stator core can be reduced. Furthermore, since the eddy current path is formed by connecting both ends of the end duct fingers with a connecting conductor using existing end duct fingers, the structure thereof is extremely simple.

[Brief explanation of the drawing]

1 and 2 are a schematic sectional view and a detailed perspective view showing the stator end of a conventional turbine generator;
FIG. 3 is a perspective view showing an end abutment plate portion having fingers, and FIG. 4 is a perspective view showing an end abutment plate portion having fingers of a stator according to an embodiment of the present invention. 2... Stator core, 4... Stator winding, 5...
End contact plate, 5a...Slot part, 5b...Teeth part, 5c...Core back part, 6a...End duct finger, 6b...Core back finger, 7
...End plate, 9...Connection conductor.

Claims (1)

[Scope of Claims] 1. A stator core, end plates disposed on both end faces thereof, end plates for tightening these stator cores and end plates, and a stator core wrapped around the stator core. The end abutment plate includes a slot portion, a teeth portion, and a core back portion, and a plurality of end duct fingers extending in the radial direction from the core back portion to the teeth portion for each teeth portion. in which both ends of a plurality of end duct fingers located on the same teeth are electrically connected to each other by a connecting conductor, and a current path is formed by these end duct fingers and the connecting conductor. A stator for a rotating electric machine characterized by: 2. A stator for a rotating electrical machine according to claim 1, characterized in that end duct fingers located in adjacent teeth portions are electrically connected by a connecting conductor to form a current path between them. . 3. A rotating electric machine according to claim 1 or 2, characterized in that the connecting conductor is electrically connected to the end duct finger at an axially outer portion of the circumferential side surface thereof. stator.