Composite Bus Bar for Generator Rotor Rectifier Assembly
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Solution Overview
Problem
Copper bus bars in generator rotor rectifier assemblies are prone to breakage due to centrifugal forces, vibration, and thermal cycling, leading to fatigue and failure.
Innovation Solution
A bus bar configuration with a first layer of beryllium copper providing structural reinforcement and a second layer of copper for enhanced electrical conductivity, where the second layer has a lower yield strength and similar thermal expansion coefficient, is used to increase rigidity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper bus bars are used for electrical conductivity, then electrical performance is improved, but mechanical strength and durability deteriorate due to breakage from centrifugal forces, vibration, and thermal cycling
Solution Approach 1:
The bus bar is constructed as a composite structure with a first layer of beryllium copper providing high strength and rigidity, and a second layer of copper providing excellent electrical conductivity. This composite design allows the bus bar to simultaneously achieve the mechanical durability needed to resist centrifugal forces and vibration, while maintaining the electrical performance required for generator operation.
Solution Approach 2:
The bus bar is divided into multiple layers with different material properties - a first layer for structural reinforcement and a second layer for electrical conductivity. This segmentation allows each layer to perform its specialized function, with the beryllium copper layer resisting mechanical stresses and the copper layer conducting electricity efficiently.
2Strength
If a single-layer copper bus bar is used, then manufacturing simplicity is maintained, but mechanical strength is insufficient to resist centrifugal forces and vibration
Solution Approach 1:
The bus bar employs a composite structure with a first layer of beryllium copper and a second layer of copper, where each layer contributes specific properties. The beryllium copper layer provides the necessary mechanical strength to resist centrifugal forces and vibration, while the copper layer ensures electrical conductivity. This composite approach achieves enhanced strength without excessive complexity.
3Strength
If beryllium copper is used for structural reinforcement, then rigidity and strength are improved, but electrical conductivity compared to pure copper is reduced
Solution Approach 1:
The bus bar is designed as a composite with a first layer of beryllium copper for structural reinforcement and a second layer of copper for electrical conductivity. This configuration allows the beryllium copper layer to provide the necessary rigidity and strength to resist mechanical stresses, while the copper layer ensures excellent electrical performance for current conduction.
Solution Approach 2:
The bus bar is segmented into functional layers: the first layer handles mechanical loading with beryllium copper, while the second layer handles electrical current with copper. This functional segmentation resolves the trade-off between mechanical strength and electrical conductivity by assigning each property to the material best suited for it.
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
The reinforced bus bar design significantly reduces the likelihood of breakage and enhances cooling, thereby improving the reliability and longevity of the generator rotor circuit.
Implementation Method 1
the bus bars are cooled by conduction to the diode packs
Implementation Method 2
a second layer is joined to the first layer and includes a second yield strength less than the first yield strength and a second coefficient of thermal expansion within 5% of the first coefficient of thermal expansion
Data Source
AI summary
A rectifier assembly includes a diode pack. A bus bar includes a first layer electrically connected to the diode pack. The first layer has a first yield strength and a first coefficient of thermal expansion. A second layer of copper is joined to the first layer and includes a second yield strength less than the first yield strength. In one example, the second layer has a second coefficient of thermal expansion within 5% of the first coefficient of thermal expansion.