Vacuum Chamber Cable Insulation Testing for Breakdown Detection
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Solution Overview
Problem
Existing test devices for electrical cable insulation are inadequate in testing breakdown strength and are not suitable for vacuum conditions, leading to unreliable detection of error points and high operational complexity.
Innovation Solution
A test device with a tightly closable and evacuable chamber that completely encloses the electrical line, allowing for vacuum conditions and using electrical feedthroughs to ensure tightness, with a housing electrode for applying test voltage and measuring breakdown strength, optionally using optical detection for arc visualization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a tong-like test vessel is used to surround a portion of the cable, then the device can be simpler in structure, but the testing reliability is reduced because only a portion of the cable can be tested and the chamber cannot be completely tight
Solution Approach 1:
The test device is divided into a chamber for enclosing the cable and a separate gas supply system. The chamber can be completely closed to achieve tight sealing, while the gas supply system is only activated when needed for specific test conditions, rather than requiring continuous gas flow to maintain sealing.
Solution Approach 2:
A seal ring is introduced as an intermediary element between the cable and the chamber wall to achieve complete sealing. This allows the chamber to be fully closed and tight, eliminating the need for continuous test gas flow to prevent air penetration, thereby improving both reliability and reducing device complexity.
2Reliability
If test gas is continuously supplied to prevent air penetration, then the chamber can remain sealed, but the effort and operational complexity increase significantly
Solution Approach 1:
The chamber is designed to be pre-sealed with a seal ring before the test begins. This preliminary sealing action eliminates the need for continuous test gas supply to maintain sealing, reducing operational complexity while maintaining reliability.
Solution Approach 2:
The continuous test gas supply function is extracted and replaced by a one-time sealing action using a seal ring. The gas supply system is retained only for optional use during testing, not for maintaining sealing, thereby significantly reducing operational complexity.
3Reliability
If test gas is used to maintain chamber sealing, then air penetration is prevented, but the detection of error points becomes unreliable due to the test gas atmosphere
Solution Approach 1:
The chamber is sealed in advance using a seal ring before introducing any test gas. This ensures that the sealing is established in a normal atmosphere, allowing for reliable error point detection. Test gas is only introduced later for specific test requirements, not for sealing purposes.
Solution Approach 2:
A seal ring is used as an intermediary to achieve complete sealing without requiring test gas. This eliminates the conflict between sealing reliability and measurement precision, as the sealing is achieved mechanically rather than through gas pressure.
4Device complexity
If only one section of the cable is surrounded by the housing, then the device structure is simpler, but the testing coverage is limited and cannot test the entire cable
Solution Approach 1:
The chamber is designed as a universal enclosure that can accommodate the entire cable or any portion of it, depending on the test requirements. The same chamber structure serves multiple functions: complete cable enclosure, partial section testing, and different cable configurations, thereby improving versatility without significantly increasing structural complexity.
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
Enables reliable, reproducible, and destruction-free testing of cable insulation under consistent conditions, reducing the need for test gas and simplifying the testing process for various cable configurations.
Implementation Method 1
The chamber is tightly closable and evacuable, so that a vacuum, but at least a negative pressure, can be created inside the chamber.
Implementation Method 2
an electrical feedthrough leads from the connection point out of the chamber
Implementation Method 3
The breakdown strength of the cable insulation is tested by applying a test voltage (or a—time-variable—test voltage curve) between the electrical line and an electrode
Data Source
AI summary
The invention relates to a test device (1) for testing the insulation of an electrical line (2), in particular a cable or a cable harness, for detecting error points in the insulation of the electrical line (2). The test device (1) comprises a scalable, evacuable chamber (3) for completely accommodating the electrical line (2) to be tested, wherein at least one electrical connection point (6), preferably in the form of a plug device part, for connecting the electrical line (2) to be tested is arranged inside the chamber (3) and an electrical feedthrough (7) leads from the connection point (6) out of the chamber (3).