Bar-Wound Stator Surge Testing via Mid-Layer Hair Pin Access
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Solution Overview
Problem
Conventional surge testing methods are inadequate for bar-wound stators as they insufficiently stress the insulating material at the mid-layer points of the windings, leading to potential undetected insulation flaws and electrical failures.
Innovation Solution
A method and system for surge testing a bar-wound stator that involves electrically connecting conductive leads to welded hair pins at the mid-point of each layer, applying a calibrated voltage surge, and measuring the voltage drop between layers to ensure thorough stress testing and detection of insulation issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional surge testing is used on bar-wound stators, then the testing process is simple, but the detection rate of insulation flaws at mid-layer points is insufficient
Solution Approach 1:
The testing process is segmented into multiple stages: conventional surge testing at phase leads, followed by targeted surge testing at mid-layer points. This segmentation allows the system to first perform a basic test and then conduct more detailed tests at critical locations, improving detection rate without requiring the complex system to be used for all tests.
Solution Approach 2:
The invention applies different testing approaches to different locations in the stator. Conventional surge testing is applied to phase leads, while a specialized test with conductive leads connected to mid-layer hair pins is applied to critical mid-layer points. This local differentiation ensures that insulation flaws at any location are detected with appropriate testing methods.
2Reliability
If surge testing is performed only at phase leads, then the testing process is straightforward, but insulation issues at mid-layer points may go undetected
Solution Approach 1:
The testing procedure performs preliminary conventional surge testing at phase leads before conducting the more detailed mid-layer testing. This preliminary action identifies obvious issues quickly, and only then does the system proceed to test mid-layer points, ensuring comprehensive coverage while maintaining operational efficiency.
Solution Approach 2:
The invention introduces conductive leads as intermediaries to connect the surge testing device to mid-layer hair pins. These intermediaries enable the testing system to access and stress the insulating material at mid-layer points that would otherwise be difficult to reach, improving reliability without significantly complicating the overall procedure.
3Quantity of substance
If the inductive load of coils changes when phases change layers, then the bar-wound design achieves high copper fill, but conventional surge testing becomes less optimal
Solution Approach 1:
The invention adds a new dimension to the surge testing approach by introducing mid-layer testing points between the conventional phase lead tests. This dimensional addition allows the testing system to probe the insulating material at critical locations within the layered structure, effectively addressing the changed inductive load characteristics of bar-wound stators while maintaining high copper fill.
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 enhances the detection rate of insulation flaws and electrical failures by directly stressing the insulating material at critical mid-layer points, providing a more comprehensive evaluation of the stator's integrity during surge testing.
Implementation Method 1
a capacitor is rapidly discharged to inject a voltage surge into the phase leads of the stator
Implementation Method 2
measuring a voltage drop between the layers at turns of the windings
Data Source
AI summary
A method for surge testing a bar-wound stator includes electrically connecting a conductive lead of a test system to a corresponding welded hair pin in each of the layers mid-way through the stator windings. A calibrated voltage surge is applied via the conductive leads into the windings of the stator at the welded hair pins. The method includes measuring a voltage drop between turns of the windings after applying the calibrated voltage surge, recording the measured voltage drop in memory of the test system, and executing a control event with respect to the stator when the measured voltage drop is more than a calibrated threshold voltage drop. A system for surge testing the bar-wound stator includes a test device having a capacitor for storing the calibrated surge voltage and a pin set that is electrically connected to the test device. The pin set includes the conductive wires and leads.