Generator Stator Core Fastening for Sag Prevention
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Solution Overview
Problem
Asynchronous generators in wind turbines face challenges in maintaining a constant air gap and reliable cooling as the depth increases, particularly above 1200mm, due to the laminated cores being attached at only two points, which can lead to sagging and potential mechanical contact between the stator and rotor.
Innovation Solution
The laminated cores are securely fastened to the stator ring at three points: two outer points and one in the middle, using screw bolts and a support ring welded to the stator ring, ensuring direct contact over the entire width and preventing sagging, thus maintaining a consistent air gap and facilitating effective cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the generator depth is increased to improve power output, then the power output is improved, but the laminated cores may sag and cause mechanical contact between stator and rotor
Solution Approach 1:
The single laminated core is divided into multiple segments (first laminated core, second laminated core, third laminated core) arranged axially. Each segment is independently fastened to the stator ring at multiple points, preventing sagging while allowing the overall generator depth to be increased for higher power output.
Solution Approach 2:
The laminated core segments are pre-fastened to the stator ring using screw bolts at multiple attachment points before the generator operates. This preliminary fastening prevents gravitational sagging from occurring during operation, maintaining the air gap stability even in deeper generators.
2Power
If the generator depth is increased to improve power output, then the power output is improved, but the cooling efficiency deteriorates due to reduced heat transfer
Solution Approach 1:
Dividing the laminated core into multiple axial segments increases the total surface area in contact with the stator ring and cooling channels. This segmentation improves heat transfer efficiency by providing more contact points for thermal conduction, even as the overall generator depth increases for higher power output.
Solution Approach 2:
The segmentation approach transforms the heat transfer problem from a single-point contact scenario to a multi-point contact scenario along the axial dimension. This dimensional expansion of contact points enhances cooling efficiency without requiring changes to the radial or tangential dimensions.
3Ease of manufacture
If the laminated cores are fastened at only two points to simplify manufacturing, then the ease of manufacture is improved, but the structural stability deteriorates in deep generators
Solution Approach 1:
The laminated core is segmented into multiple sections, each fastened at multiple points. While this increases the total number of fastening points, it maintains manufacturing simplicity by using standardized fastening procedures repeated across segments, rather than requiring complex single-point fastening mechanisms.
Solution Approach 2:
Multiple fastening points are strategically positioned at specific locations (attachment points) on each laminated core segment. This local concentration of fastening points provides maximum structural stability with minimal fastening complexity, ensuring each segment is securely held without unnecessary fastening throughout the entire core structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures a consistent air gap and reliable heat transfer, preventing mechanical contact and ensuring safe operation and efficient cooling in deeper generators, even up to 1200mm depth, by maintaining direct contact between the laminated cores and the stator ring.
Implementation Method 1
The sheets of the laminated core are classic dynamo sheets. These are laid manually or mechanically according to a specific pattern and are also held by screw bolts that are tightened after completion of the laminated core in order to press the individual sheets together.
Implementation Method 2
a support ring 7 in the example shown. This support ring is - as in the 1 to recognize - also penetrated by the bolts 6 and fixed by means of a weld 8 on the stator ring 1 at point 13.
Data Source
AI summary
The invention relates to an electrical generator (3) comprising a stator (2) which has windings lying in grooves (5) formed by metal sheets and which has a predetermined diameter and a predetermined depth. The metal sheets form a laminated core (4, 9, 10) which is penetrated by threaded bolts (6), the front and rear end of the laminated core (4, 9, 10) being mounted on a ring (1) of the stator (2). According to the invention, an additional mounting point (13) for the laminated core is formed on the stator ring (1), said mounting point (13) being located approximately in the center of the stator ring (1).