Stator Coil Removal Using Rotor Alignment in Wind Generators
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Solution Overview
Problem
In large electrical machines, such as direct drive wind turbine generators, it is difficult to access and replace damaged coils in the stator, especially when they are located in hard-to-reach areas, leading to time-consuming and labor-intensive processes.
Innovation Solution
A method and tool system that allows for the removal and installation of stator coils by rotating the rotor to align a replacement tool with the damaged coil, enabling efficient extraction and reinstallation from a more accessible position, utilizing a tool with a holding and anchoring mechanism to securely manage the coils during the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If coils are removed directly from hard-to-reach areas of the stator, then the replacement process can be completed, but the operation becomes time-consuming and labor-intensive
Solution Approach 1:
A rotor assembly is used as an intermediary tool to transfer coils from hard-to-reach stator positions to easily accessible positions. The rotor assembly with its holding portion grasps the coil and transports it axially out of the stator, mediating between the difficult extraction position and the easy removal position.
Solution Approach 2:
Instead of removing coils directly from hard-to-reach areas, the method inverts the approach by first inserting the rotor assembly at an easily accessible position, then using it to extract coils from difficult positions and bring them out at easy positions. The process works backwards from the problem area to the solution area.
2Ease of repair
If multiple coils are removed to access a damaged coil in hard-to-reach areas, then the damaged coil can be replaced, but the process becomes more complex and time-consuming
Solution Approach 1:
The rotor assembly serves as a mediator that can reach into the stator from an accessible position and directly grasp the damaged coil regardless of its location. This eliminates the need to remove multiple other coils to access the damaged one, simplifying the repair process.
Solution Approach 2:
The rotor assembly is preliminarily positioned at an easily accessible location before the actual coil extraction. This preliminary positioning allows the tool to then reach back and grasp the damaged coil directly, avoiding the need to sequentially remove multiple coils.
3Reliability
If coils are extracted from positions close to the wind turbine tower or nacelle, then all coils can be replaced, but the operation becomes dangerous and difficult due to limited access space
Solution Approach 1:
The rotor assembly acts as a safe intermediary that performs the dangerous extraction work in hard-to-reach areas. Operators can safely insert and operate the rotor assembly from accessible positions, allowing it to grasp and extract coils from dangerous locations without exposing personnel to hazardous spaces.
Solution Approach 2:
Instead of having operators work directly in dangerous hard-to-reach areas to extract coils, the method inverts the approach by using the rotor assembly to reach into dangerous areas from safe accessible positions, bringing the coils out to safe locations for removal.
Data Source
AI summary
The present disclosure relates to methods and tools for mounting and/or removing active parts of a stator of an electrical machine, e.g. a generator. The present disclosure also relates to rotors, stators and generators. A method comprises removing one or more active rotor parts of a rotor of an electrical machine when the rotor is in a removal starting position, arranging a replacement tool in a gap left by the removed active rotor parts, rotating the rotor to an alignment position such that the replacement tool is radially aligned with an active stator part to be removed, picking the active stator part to be removed with the replacement tool, rotating the rotor to an extraction position, and removing the active stator part from the rotor.