Multi-turn Coil Insulation Segmentation for Stator Stress Reduction
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Solution Overview
Problem
Multi-turn coils in dynamoelectric machines face insulation damage due to excessive stress during installation, leading to electrical, thermal, and mechanical failures, as existing solutions have not adequately addressed the deformation and stress issues.
Innovation Solution
The method involves initially applying insulation to slot regions of the coil before insertion into the stator core, leaving loop regions without ground insulation, completing the insulation post-installation, and using a vacuum pressure impregnation system or resin-containing tapes to ensure effective insulation without initial turn insulation in some cases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulation is applied to the entire coil before insertion, then electrical insulation is ensured, but excessive stress during installation causes cracks or damage in the insulation system
Solution Approach 1:
The insulation system is segmented into two distinct parts: ground insulation applied to slot regions before insertion, and turn insulation applied to loop regions after insertion. This segmentation allows each insulation type to be applied at the optimal time, preventing stress damage while ensuring complete electrical insulation.
Solution Approach 2:
Ground insulation is applied to the slot regions of the coil before insertion into the stator core. This preliminary action ensures that the portion of the coil subject to insertion stress does not have insulation that could crack, while still providing necessary electrical insulation at the insertion points.
2Reliability
If turn insulation is applied before insertion, then electrical insulation is complete, but the insulation system becomes more vulnerable to stress-induced damage
Solution Approach 1:
Turn insulation application is segmented into two stages: slot regions receive turn insulation before insertion, while loop regions receive turn insulation after insertion. This eliminates the vulnerability of having complete turn insulation applied beforehand, while still ensuring electrical insulation completeness.
Solution Approach 2:
Only the necessary preliminary insulation (ground insulation in slot regions) is applied before insertion. The complete turn insulation is deferred until after insertion, when stress concerns are eliminated, ensuring both electrical completeness and stress resistance.
3Strength
If insulation is applied in multiple stages, then stress damage is minimized, but the manufacturing process becomes more complex
Solution Approach 1:
The insulation process is segmented by both location (slot vs. loop regions) and timing (before vs. after insertion). While this creates multiple steps, each step uses standard insulation application techniques, and the segmentation aligns with natural manufacturing stages, making the complexity manageable and organized.
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 approach reduces insulation damage and enhances the reliability of multi-turn coils by allowing for controlled application of insulation post-installation, minimizing stress and ensuring robust electrical and thermal performance.
Implementation Method 1
using a vacuum pressure impregnation system or resin-containing tapes to ensure effective insulation without initial turn insulation in some cases
Data Source
AI summary
A method of fabricating a dynamoelectric machine utilizing multi-turn coils includes manufacturing a multi-turn coil having turn and ground insulation and installation of the coil into the stator core of the machine. The loop regions of the coil have no ground insulation during installation and the ground insulation at the loop regions is completed after installation of the coil.