Coil Extraction Tool for Stator Iron Protection
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Solution Overview
Problem
The existing method for removing globally vacuum impregnated coils from dynamoelectric machine core slots is time-consuming, complex, and prone to stator iron damage due to the high extraction force required and difficulties in handling copper materials.
Innovation Solution
A method using three specialized tools: a cleaver for cutting the coil, an upender tool for partially removing the coil, and an extraction tool for serially pulling segments of the coil out of the slot, employing hydraulic forces to minimize damage and facilitate efficient removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the prior art method of drilling and tapping dozens of holes into each stator half coil with hydraulic cylinders is used, then the coil can be extracted from the slot, but the process is extremely time-consuming and complex requiring special tooling jigs
Solution Approach 1:
The extraction process is divided into discrete segments corresponding to individual slots. The extraction tool is designed to work on one slot at a time, extracting one coil segment at a time, rather than requiring simultaneous extraction from multiple slots. This segmentation allows for simpler, more manageable tooling that can be quickly repositioned between slots, dramatically reducing overall extraction time and complexity.
2Productivity
If high extraction force is applied to remove globally vacuum impregnated coils, then the coil can be removed from the slot, but stator iron damage occurs
Solution Approach 1:
The invention introduces a specialized extraction tool that acts as an intermediary between the hydraulic cylinder and the coil. This tool distributes the extraction force across multiple contact points along the coil's length and width, preventing concentrated loads that would damage the stator iron. The tool's design includes force-distributing elements that gently lift and separate the coil from the slot without transmitting damaging forces to the stator core.
Solution Approach 2:
The extraction process utilizes controlled parameter changes, specifically applying extraction force gradually and incrementally rather than as a single high-magnitude load. The hydraulic system provides controlled, progressive force application that allows the coil to be slowly separated from the slot, reducing peak forces that would cause stator iron damage while still achieving complete coil removal.
3Ease of manufacture
If drilling and tapping operations are performed on copper coils, then extraction points can be created, but copper chips are generated and tools may become stuck
Solution Approach 1:
The invention extracts or removes the need for drilling and tapping operations entirely. Instead of creating extraction points through subtractive manufacturing that generates copper chips, the design uses the coil's existing structure and applies extraction force through contact with the coil's outer surface. This eliminates the harmful chip generation problem while still achieving effective coil extraction.
4Manufacturing precision
If special tooling jigs are used for drilling and tapping to avoid stator iron damage, then precision can be maintained, but the process becomes more complex and time-consuming
Solution Approach 1:
The extraction tool is designed to be self-positioning and self-aligning, eliminating the need for complex pre-positioned tooling jigs. The tool automatically locates and aligns with the slot and coil geometry, providing the necessary precision without requiring elaborate fixture systems. This self-service capability simplifies the overall process while maintaining protection of the stator iron through precise, controlled force application.
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
The method allows for quick and efficient removal of coils with reduced risk of stator iron damage, creating interlaminar shear forces that separate individual strands for easy recycling and handling, while avoiding the creation of copper chips and minimizing operational time.
Implementation Method 1
A piston is extended to lower the blade to the reaction plate to cut through the coil
Implementation Method 2
When the piston rod is extended it forces the coil to be raised within the slot
Implementation Method 3
the hydraulic cylinders that press the gripping plates towards each other to firmly grip the coil
Implementation Method 4
the extraction tool exerts such large forces in bending each successive segment radially inward and up and out of the slot that this action creates tremendous interlaminar shear forces
Data Source
AI summary
A set of tools for removing a half turn of a coil from a slot of a dynamoelectric machine. The set of tools includes a coil cutting tool for cutting the coil, an upending tool that grips the coil at an end of the coil where the coil was cut and hydraulically or pneumatically lifts the end of the coil at least partially out of the slot, and an extraction tool that hydraulically or pneumatically grips the upended portion of the coil and pulls the coil from the slot hydraulically or pneumatically a segment at a time.