Generator Stator Frame Keybar Replacement
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Solution Overview
Problem
Existing methods for replacing a stator core in a power generator stator frame, especially after prolonged use, are difficult due to the need to handle and install the core in an upright position, which is challenging and inefficient, particularly when using dove-tail shaped keybars.
Innovation Solution
The method involves replacing dove-tail shaped keybars with rounded keybars and modifying the frame beams to create radial clearance, allowing for easier axial sliding and installation of a new stator core using a horizontal process, facilitated by using a portable milling machine to bevel the inner corner edges of the frame beams and installing new keybars with counter-bored holes for secure support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dove-tail shaped keybars are used to support the stator core, then the stator core is securely held in place, but the replacement process becomes difficult and time-consuming requiring the frame to be upright
Solution Approach 1:
The patent changes the geometric parameters of the keybar engagement surface from a dove-tail shape to a rounded shape. This parameter change allows the stator core to be installed horizontally using gravity assistance, dramatically reducing installation time and complexity while maintaining secure holding through the rounded engagement geometry
2Ease of manufacture
If the stator frame is placed in an upright position for core replacement, then the core can be installed, but the process becomes very difficult and complex
Solution Approach 1:
Instead of installing the stator core in the traditional upright position, the patent inverts the installation approach by using a horizontal frame position. The rounded keybars enable the core to be guided into place horizontally using gravity, simplifying the installation process and eliminating the need for complex upright positioning equipment
3Ease of operation
If rounded keybars are used instead of dove-tail shaped keybars, then the installation process is simplified and can be done horizontally, but the secure fit mechanism changes
Solution Approach 1:
The patent applies spheroidality by using rounded keybars with curved engagement surfaces instead of straight dove-tail shapes. The rounded geometry provides a self-aligning feature that guides the stator core into place during horizontal installation, while the curvature of the engagement surface maintains secure fitting through contact geometry that distributes loads effectively
Data Source
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AI summary
A method of servicing a stator frame of a power generator. The method includes removing a first stator core from a main housing of the stator frame, removing a plurality of first dove-tail shaped keybars that extend axially within and are coupled to a main support structure forming part of the main housing, and installing a plurality of second keybars in the main support structure. The second keybars are adapted to support a second stator core. Each of the second keybars has a generally rounded engagement surface and the second stator core includes recesses with shapes corresponding to the generally rounded engagement surfaces of the second keybars such that the second stator core can be securely supported in the main support structure by the second keybars.