Bus Bar Bolted Joint With Carbon Nanotube Constant Torque Layer
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Solution Overview
Problem
Bolted connections in high-power copper busbars require frequent retorquing due to temperature changes and current fluctuations, leading to maintenance costs, complexity, and system downtime, with potential loss of conductivity causing heat buildup.
Innovation Solution
Utilizing a constant pressure material, such as carbon nanotubes, to maintain torque within specified ranges, eliminating the need for periodic retorquing by compensating for physical movement and maintaining electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bolted connections are used to connect busbars, then mechanical strength and current handling capability are improved, but frequent retorquing is required due to temperature changes and current fluctuations
Solution Approach 1:
The patent changes the material parameter from traditional rigid washers to elastic constant pressure washers that maintain constant force despite temperature and current-induced dimensional changes. This elastic property allows the washer to compensate for expansion and contraction, maintaining connection stability without requiring frequent retorquing.
Solution Approach 2:
The patent uses composite construction combining rigid busbar materials with elastic constant pressure washer materials. This composite approach allows each component to perform its optimal function - the rigid busbars provide structural strength while the elastic washers provide compensation for thermal and electromagnetic expansion, together solving the reliability issue.
2Reliability
If periodic retorquing is performed to maintain connection stability, then connection reliability is improved, but maintenance costs and system downtime increase
Solution Approach 1:
The elastic constant pressure washers perform self-adjustment by automatically compensating for dimensional changes in the busbars due to temperature and current fluctuations. This self-service mechanism eliminates the need for external intervention through periodic retorquing, thereby reducing maintenance costs and system downtime while maintaining connection reliability.
3Device complexity
If bolted connections are used without frequent retorquing, then maintenance complexity is reduced, but conductivity loss and heat buildup occur
Solution Approach 1:
The patent changes the mechanical property of the connection system by introducing elastic constant pressure washers that maintain optimal contact pressure despite dimensional changes. This parameter change ensures consistent electrical conductivity without requiring complex maintenance procedures, preventing heat buildup while keeping maintenance simple.
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
Reduces maintenance costs and downtime while ensuring consistent conductivity by using carbon nanotubes to resist movement and compensate for thermal and current-induced stress in bolted connections.
Implementation Method 1
The constant pressure material can be permanently (or semi-permanently) elastic and can consistently spring back as a bolt expands and contracts
Implementation Method 2
the constant pressure material can be conductive and can advantageously be arranged for supporting electrical communication between or among two or more conductors
Implementation Method 3
as a bolt expands and contracts, such as due to changes in heat which may be caused by changes in current flow
Data Source
AI summary
An electrical connector system can include a first conductor comprised of a first electrically conductive material, a second conductor comprised of the first electrically conductive material, a fastener configured to couple the first conductor to the second conductor, and a constant torque material comprised of a second electrically conductive material. The constant torque material can be disposed in electrical communication with the first conductor and the second conductor. The constant torque material can include carbon nanotubes disposed on a substrate.