Segmented Electric Motor Assembly With Stable Air Gap Alignment
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Solution Overview
Problem
The transportation and assembly of large-diameter electric machines are hindered by the magnetic attraction force between stator and rotor segments, which increases transportation difficulty and complexity, especially for megawatt-class wind turbines, where the magnetic attraction can reach several tons, posing challenges in maintaining original performance and minimizing deformation during segmentation.
Innovation Solution
The electric machine is segmented into stator and rotor segments, which are then assembled using a fixing device with a base, arc-shaped first fixtures, and adjustable second fixtures to maintain a predetermined radial gap, allowing for easy assembly and disassembly, and facilitating transportation by ensuring a stable air gap is maintained during the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the electric machine is segmented into stator and rotor segments for transportation, then the transportation difficulty is reduced, but the magnetic attraction force between segments increases the assembly complexity
Solution Approach 1:
The patent applies preliminary action by pre-assembling stator and rotor segments into complete units on a fixing device before transportation. The fixing device maintains the air gap between segments during assembly, and the segments are pre-positioned and fixed together as complete stator and rotor assemblies. This preliminary assembly eliminates the need to handle individual segments during final assembly, reducing assembly complexity despite the segmented transportation approach.
2Device complexity
If stator and rotor segments are assembled without a fixing device, then the device complexity is reduced, but the air gap maintenance and assembly precision deteriorate
Solution Approach 1:
The fixing device serves as an intermediary tool during the assembly process. It provides a structured platform with positioning features that maintain the predetermined air gap between stator and rotor segments. The fixing device includes positioning elements and support structures that ensure precise alignment and consistent spacing, acting as a mediator that enables precise assembly without requiring complex permanent fixtures in the final product.
3Ease of operation
If segments are assembled without maintaining a predetermined air gap, then the assembly process is simplified, but the magnetic attraction force increases causing deformation and performance degradation
Solution Approach 1:
The fixing device applies preliminary anti-action by providing mechanical support and spacing structures that counteract the magnetic attraction force between stator and rotor segments during assembly. The device maintains the predetermined air gap through positioning elements and support structures that resist the magnetic pull, preventing deformation of segments. This preliminary counter-action ensures segments are properly positioned before the magnetic force can cause deformation, maintaining both structural integrity and assembly simplicity.
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 method enables quick and easy assembly of large-diameter electric machines, reduces transportation difficulties, and minimizes the risk of performance degradation and reassembly errors by maintaining a consistent air gap, thus improving assembly quality and reducing the complexity of reassembling the segmented components.
Implementation Method 1
there is a large magnetic attraction force at a predetermined air gap in a radial direction between stator segments and rotor segments
Data Source
AI summary
An assembly method and a fixing device for an electric motor are provided. The assembly method includes: carrying out preparation, wherein a stator of the electric motor is segmented, in the circumferential direction, into at least two stator segments, and a rotor of the electric motor is segmented, in the circumferential direction, into at least two rotor segments; carrying out pre-assembly, wherein the stator segments and the rotor segments are coaxially fixed to fixing devices to form segment modules, and predetermined gaps are maintained radially between the stator segments and the rotor segments; carrying out adjustment, wherein at least two fixing devices are moved and adjusted such that the stator segment and the rotor segment of the adjacent segment modules are mutually attached and aligned with each other along segmental end faces in the circumferential direction; carrying out assembly; and carrying out dismounting, and dismounting the fixing devices.