JPH01321836A - Cooling method for stator winding of turbine generator - Google Patents

Abstract

PURPOSE:To form the temperature distribution of a rotor winding uniformly in the axial direction by setting the sectional area of cooling holes, penetrating through in a radial direction of slots housing the rotor winding, smaller in the central part of the rotor and larger in its shaft end part. CONSTITUTION:A sectional area of cooling holes 4 of a rotor in its radial direction is varied. That is, the sectional area of the cooling holes 4 is formed larger in the shaft end part of a shaft and smaller in the central part. Thus, because resistance of ventilating air is balanced over the total unit in a shaft direction, the air passing through the cooling holes 4 of the rotor is almost in a uniform amount in the total unit in the shaft direction. Consequently, uniform temperature distribution in a rotor winding 3 is obtained over the total unit in the shaft direction, and a turbine generator provided with the rotor winding of high utilization factor can be obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for cooling rotor windings of a turbine generator by providing ventilation passages at the bottom of slots in the axial direction of the rotor and cooling holes in the radial direction of the rotor. [Conventional technology]

Figure 1 is a partial cross-sectional view showing the cooling air passage of the rotor of a turbine generator. Due to the ventilation effect accompanying the rotation of the rotor, the cooling air passes through the slot bottom ventilation passage 6 and passes through a plurality of cooling holes in the radial direction. The rotor winding 3 is cooled. FIG. 2 is a partial cross-sectional view taken in a direction perpendicular to the axis of the turbine generator rotor. The rotor winding 3 is accommodated in a slot provided in the iron core 5, insulated with a mock insulation 2, and a draft 1 is provided on the outer diameter side. The rotor winding 3 is driven in to prevent it from coming off. Cooling air passing through the slot bottom ventilation passage 6 on the inner diameter side running in the axial direction passes through the cooling hole 4 passing through the slot in the radial direction and exits to the outer diameter side to cool the rotor winding 3. Conventionally, as a rotor winding cooling method for this type of turbine generator, the pitch of the cooling holes 4 bored in the rotor was machined to the same pitch of 6 or the same throughout the entire axial direction.

[Problem to be solved by the invention]

However, with this method, the distribution of cooling air in the rotor is not uniform due to the fact that the ventilation resistance is large at the shaft end and small at the center of the shaft, and due to the influence of dynamic pressure. As shown by the solid line in Figure 3, there was a drawback in that the amount of air was large in the center of the shaft, and the amount of air decreased toward the ends of the shaft. Furthermore, due to this air volume distribution, the temperature distribution of the rotor windings also had the disadvantage that the temperature was low at the center of the shaft and high toward the ends of the shaft. The purpose of this invention is to provide a cooling method that takes into consideration the distribution of ventilation resistance and dynamic pressure, distributes a uniform air volume over the combined shaft, and uniformizes the temperature distribution of the rotor winding, in order to eliminate the conventional drawbacks. shall be.

[Means to solve the problem]

According to the present invention, the above object is achieved by making the cross-sectional area of the cooling holes that radially pass through the slots containing the windings of the rotor smaller in the center of the rotor and larger in the shaft end, or This is achieved by keeping the cross-sectional area the same and making the pitch of the cooling holes wider in the axial direction at the center and narrower in the axial direction at the ends of the shaft.

[Function] According to this invention, the cross-sectional area of the cooling holes that radially penetrate through the slots housing the rotor windings is made smaller at the center of the rotor and larger at the shaft ends, so that Therefore, the temperature distribution of the rotor winding can be made uniform in the axial direction. Furthermore, the temperature distribution of the rotor winding can be made uniform in the axial direction by making the pitch of the cooling holes wider in the axial direction at the center and narrower in the axial direction at the ends of the shaft.

【Example】

As an embodiment of the present invention, there is a method of changing the radial cross-sectional area of the cooling holes 4 of the rotor. That is, the cross-sectional area of the cooling holes is made large at the ends of the shaft, and the cross-sectional area of the cooling holes is made small at the center of the shaft. Alternatively, there is a method in which the cross-sectional area of the slot bottom ventilation passage 6 is made larger at the ends of the shaft and smaller at the center of the shaft. In another embodiment of the present invention, the cross-sectional area of the cooling holes 4 and the cross-sectional area of the ventilation passage 6 are the same, and the pitch of the cooling holes 4 is a narrow pitch in the axial direction at the end of the shaft, and a pitch in the axial direction at the center of the shaft. There is a way to make the pitch wide. By any of the above methods, a substantially uniform air volume can be obtained over the entire length of the shaft, as shown in the air volume distribution indicated by the dotted line in FIG.

【Effect of the invention】

According to this invention, since the ventilation resistance is balanced over the entire axial direction, the amount of air passing through the cooling holes of the rotor becomes substantially uniform over the entire axial direction. Therefore, the temperature distribution of the rotor winding is uniform throughout the entire axial direction, making it possible to provide a turbine generator having a rotor winding with a high utilization rate. Although the above description has been made regarding a cylindrical massive rotor, the same can be applied to a laminated rotor.

[Brief explanation of the drawing]

Figure 1 is a partial cross-sectional view showing the cooling air passage of the rotor winding of a turbine generator, Figure 2 is a partial cross-sectional view in a direction perpendicular to the axis of the turbine generator rotor, and Figure 3 is a partial cross-sectional view of the rotor. FIG. 3 is an explanatory diagram showing the relationship between the axial position and the amount of cooling air of the rotor winding. 1: Wedge, 3: Rotor winding, 4: Cooling hole, 5: Iron core, 6:
Slotted bottom ventilation channel. Figure 1

Claims (1)

[Claims] 1) In a turbine generator in which the rotor windings are cooled by ventilation through cooling holes that radially penetrate through the slots housing the windings via the slot bottom ventilation passage in the axial direction of the rotor, the cooling holes Either the cross-sectional area of the cooling holes is made smaller in the center of the rotor and larger at the shaft end, or the cross-sectional area of the cooling holes is the same and the pitch of the cooling holes is made wider in the axial direction in the center of the rotor and larger in the shaft end. A method for cooling a rotor winding of a turbine generator, characterized by narrowing the rotor winding in a direction.