Isolated Generator Stator Coil Connector Assembly
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Solution Overview
Problem
Existing connector systems for stator coils in electrical generators face challenges with positional misalignment, require complex and costly brazing, and suffer from mechanical creep and increased stress due to stringent alignment requirements and the use of conductive bolting hardware.
Innovation Solution
A connector assembly with isolated conductive connecting bars and couplers that allow relative movement, eliminating the need for through-stud connections and using fasteners and receivers to maintain electrical and mechanical isolation via an air gap, along with a low-profile fastener receiving device providing pre-load biasing to compensate for mechanical creep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional through-stud bolting connections are used to connect coil sections, then mechanical strength and electrical conductivity are improved, but positional misalignment tolerance deteriorates and mechanical creep increases
Solution Approach 1:
The connection system is segmented into separate mechanical connection elements (bolts, washers) and electrical connection elements (conductive plates, contact surfaces). The mechanical fasteners provide structural strength while the dedicated conductive contact surfaces ensure electrical continuity, allowing each element to be optimized independently for its specific function without compromising the other.
Solution Approach 2:
Flat conductive plates or contact surfaces are introduced as intermediary elements between the coil sections and fasteners. These intermediaries distribute the mechanical load over a larger area, reducing stress concentration and allowing for greater positional misalignment while maintaining both mechanical strength and electrical conductivity.
2Manufacturing precision
If stringent alignment requirements are imposed on connector assembly, then manufacturing precision is improved, but assembly complexity and cost increase
Solution Approach 1:
The design changes the geometric parameters of the connection interface, specifically using flat contact surfaces with sufficient area to accommodate misalignment. By increasing the contact area and adjusting the distribution of fasteners, the system tolerates greater positional variations without requiring high-precision alignment during assembly.
3Reliability
If conductive bolting hardware is used for connection, then electrical conductivity is improved, but eddy current losses increase
Solution Approach 1:
The electrical conduction function is extracted from the mechanical fasteners and assigned to separate dedicated conductive contact surfaces or plates. This separation allows the mechanical fasteners to be non-conductive or have minimal conductive path, thereby eliminating eddy current losses in the fasteners while maintaining excellent electrical conductivity through the optimized contact surfaces.
4Device complexity
If mechanical creep is not compensated for in the connection design, then device complexity is reduced, but connection reliability deteriorates over time
Solution Approach 1:
The connection design incorporates pre-compression or pre-load through the fastener system that compensates for anticipated mechanical creep. By applying a controlled initial compressive force to the contact surfaces, the design anticipates and counteracts the gradual relaxation that occurs over time, maintaining consistent electrical and mechanical connection reliability without requiring complex active compensation mechanisms.
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 solution simplifies assembly, reduces mechanical creep, and decreases stress on coils, while allowing for easier serviceability and reduced eddy current losses by providing isolated, parallel conductive paths for current flow.
Implementation Method 1
the shank portion configured for providing an interference fit within the member sufficient for locking the device against rotation therein
Implementation Method 2
the flange portion configured to act as a disc spring for establishing, in conjunction with the fastener, urging the device against the surface of the header (18), a pre-load biasing force in a force plane against the header, sufficient to compensate for mechanical creep in a connection between the header and the connecting bar
Data Source
AI summary
A connector assembly (12) for electrically and mechanically connecting via bolting, the top and bottom stator coil sections (14, 16) of an electrical generator comprising at least one pair of stator coil sections (14, 16) having spaced apart upper coil headers (18, 20) and lower coil headers (22, 24), each comprising a conductive material to provide at least two parallel paths for passing respective flows of electric current; first and second connectors (26, 28) including respective couplers (36, 38, 40, 42) for connecting the headers (18, 20, 22, 24), wherein the first and second connectors (26, 28) are electrically and mechanically isolated from one another via an air gap (34) therebetween so that none of the couplers (36, 38, 40, 42) bridge the air gap (34) and thereby allow relative movement between the first and second connectors (26, 28).