Vacuum Circuit Breaker Contacts With Cold-Sprayed Weldable Coating
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Solution Overview
Problem
Existing vacuum circuit breakers face limitations in the mechanical and electrical connection of contact pieces to other components, leading to restricted material selection, increased wear, and maintenance issues due to asymmetric current diversion and mechanical faults.
Innovation Solution
A method involving cold gas spraying of aluminum or aluminum alloys onto copper or copper alloy contact pieces, followed by welding these coated sides to current transfer contacts, providing a homogeneous and durable connection that eliminates the need for mechanical fastening and enhances vacuum integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper contact pieces are mechanically connected to current transfer contacts via screwing or clamping, then assembly is simple and disassemblable, but the connection is susceptible to mechanical faults and wear
Solution Approach 1:
The patent replaces the mechanical connection system (screws, clamps) with a welding process. The copper contact piece is directly welded to the current transfer contact, eliminating mechanical fastening components. This substitution removes the susceptibility to mechanical faults and wear associated with screwing or clamping, while simplifying the final assembly process.
Solution Approach 2:
The patent creates a composite structure by joining copper contact pieces to current transfer contacts through welding. This composite connection combines the electrical conductivity of copper with the structural integrity of the current transfer contact, achieving both reliability and simplified assembly in a single integrated joint.
2Reliability
If only copper or copper alloys are used for contact pieces, then thermal and electrical properties are optimal, but material selection is restricted and mechanical connection options are limited
Solution Approach 1:
The patent employs composite material construction by welding copper contact pieces to current transfer contacts. This allows the contact piece to maintain optimal electrical and thermal properties through copper, while the welded joint provides enhanced mechanical strength and connection versatility, effectively combining the advantages of different materials.
Solution Approach 2:
By replacing mechanical connection methods with welding, the patent expands the effective material selection. The welding process enables joining of copper with various current transfer contact materials (such as aluminum, copper alloys, or other conductive materials), thereby increasing adaptability while maintaining electrical performance.
3Ease of manufacture
If asymmetric current diversion occurs in mechanical connections, then connection simplicity is maintained, but wear increases and fault-free operation time decreases
Solution Approach 1:
The patent replaces mechanical connections that cause asymmetric current diversion with a welded joint. The welding process creates a homogeneous, integrated connection that ensures symmetric current distribution across the contact interface, eliminating the asymmetric stress and wear patterns that limit fault-free operation time in mechanical connections.
Solution Approach 2:
The welded connection creates a homogeneous joint between the copper contact piece and current transfer contact. This homogeneity ensures uniform current density distribution across the contact surface, preventing localized overheating and asymmetric wear, thereby extending the duration of fault-free operation while maintaining connection simplicity.
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 solution results in a long-lasting, low-maintenance vacuum switching chamber with improved electrical and magnetic field diversion, extended fault-free operation, and reduced wear by ensuring a homogeneous connection and thick, mechanically robust aluminum layers that maintain vacuum integrity.
Implementation Method 1
coating the electrical contact pieces with aluminum or an aluminum alloy, the coating of the contact pieces taking place by means of a cold gas spraying method
Implementation Method 2
welding each of the sides coated in method step b) to a current transfer contact
Data Source
AI summary
A method for producing an electrical switch contact arrangement for a vacuum circuit breaker includes the following steps: a) providing two electrical contact pieces made of copper or a copper alloy; b) coating the electrical contact pieces with aluminum or an aluminum alloy, the coating of the contact pieces taking place by means of a cold gas spraying method; c) welding each of the sides coated in method step b) to a current transfer contact; and d) arranging the units obtained in method step b) inside the vacuum circuit breaker. There is also described an electrical switch contact arrangement for a vacuum circuit breaker with the contact pieces produced by the method according to the invention.