Electric Machine End Ring with Rotor Core Tab
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Solution Overview
Problem
Induction motors and generators often experience failure of the electrically conductive end ring due to high centripetal forces at high rotational speeds, which compromises the robustness of the rotor's electrical communication system.
Innovation Solution
The integration of reinforcing tabs with the end ring, formed from conductive material, which are coupled with the rotor core's laminations to resist centrifugal forces generated during rotation, enhancing the structural integrity and electrical communication between axially extending conductive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional end ring is used in the rotor, then the electrical communication between conductor bars is provided, but the end ring fails due to high centripetal forces at high rotational speeds
Solution Approach 1:
The end ring is segmented into multiple sections by introducing reinforcing ribs that divide the continuous end ring structure. This segmentation allows each segment to independently withstand centrifugal forces, preventing the failure that occurs in conventional continuous end rings at high rotational speeds.
Solution Approach 2:
Reinforcing ribs are strategically positioned at specific locations within the end ring where centrifugal forces are most intense. This local reinforcement provides enhanced structural integrity precisely where needed, rather than uniformly strengthening the entire end ring, thus maintaining electrical communication while resisting high centripetal forces.
2Strength
If the end ring is made robust to resist centrifugal forces, then the structural integrity is improved, but the device complexity increases
Solution Approach 1:
The reinforcing ribs are integrated directly into the end ring structure, merging the reinforcement function with the electrical conduction function. This combination approach strengthens the end ring to resist centrifugal forces while maintaining electrical communication between conductor bars, without requiring separate additional components.
Solution Approach 2:
The end ring is constructed using composite material properties by combining conductive material with reinforcing structural elements. This composite approach provides both the electrical conductivity needed for motor operation and the mechanical strength to withstand high-speed rotation, achieving dual functionality in a single integrated structure.
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 provides a robust end ring construction that effectively resists centrifugal forces, thereby enhancing the durability and reliability of the electric machine's operation as both an induction motor and generator.
Implementation Method 1
rotation of the rotor about the axis generates centrifugal forces acting on the end ring and the tab resists a portion of the centrifugal forces
Data Source
AI summary
An electric machine with a stator and a rotor. The rotor core is formed by a stack of laminations with the laminations being generally planar and oriented substantially perpendicular to the rotational axis. One of the laminations includes an axially projecting tab. An electically conductive end ring is located at an axial end of the rotor core and is in communication with a plurality of axially extending conductor bars on the rotor core. The tab is coupled with the end ring and resists a portion of the centrifugal forces acting on the end ring during rotation of the rotor. A plurality of such tabs may be used to provide support to the end ring. A method of manufacture is also disclosed.