Segmented End-Ring for Induction Motor Heat Reduction
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Solution Overview
Problem
The existing methods for manufacturing induction motors with copper rotor bars are hindered by the difficulty of copper die casting, requiring expensive equipment and limiting mass production due to the high boiling point of copper, and the use of star-like end-rings increases processing time and cost, while traditional end-ring structures face issues with heat generation and efficiency.
Innovation Solution
An end-ring structure for induction motors composed of multiple separate pieces, either copper or aluminum, configured in a ""-shape with insertion grooves that are brazed to copper rotor bars, reducing the number of pieces needed and enhancing area coverage for improved efficiency and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If copper die casting is used to manufacture the induction motor, then the efficiency is improved due to low resistivity of copper, but the manufacturing cost increases and mass production is limited due to high boiling point of copper requiring expensive equipment
Solution Approach 1:
The end-ring is divided into multiple separate pieces (first through fourth pieces) that can be manufactured independently and then assembled. This segmentation allows the use of simpler, less expensive manufacturing processes for each piece while maintaining the overall copper construction for low resistivity, thereby reducing manufacturing cost while preserving efficiency.
2Strength
If a star-like end-ring structure is used, then the coupling with rotor bars is improved, but the processing time and manufacturing cost increase
Solution Approach 1:
The end-ring is segmented into multiple simpler pieces rather than manufacturing a complex star-like shape as a single piece. This reduces processing time and manufacturing complexity while maintaining effective coupling through the brazing process that joins the segmented pieces to the rotor bars.
Solution Approach 2:
Multiple separate end-ring pieces are combined through brazing to form the complete end-ring structure. This merging approach achieves the same coupling function as a star-like design but with simpler individual components that are faster and less costly to manufacture.
3Ease of manufacture
If traditional end-ring structures are used, then the manufacturing process is simple, but heat generation increases and efficiency decreases
Solution Approach 1:
The end-ring is divided into multiple pieces with specific geometries (first and second pieces with first geometry, third and fourth pieces with second geometry). This segmentation optimizes the electrical path and reduces eddy current losses, thereby reducing heat generation while maintaining manufacturing simplicity through standardized piece designs that can be efficiently brazed together.
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 configuration reduces heat generation, enhances efficiency by increasing the end-ring area, simplifies the manufacturing process, and decreases production costs by minimizing the number of pieces required, thus improving overall system performance and mass production capabilities.
Implementation Method 1
upper and lower copper rotor bars and the end-ring portion are coupled with each other by brazing
Data Source
AI summary
A rotor comprises a rotor core comprising a rotational axis and a plurality of slots, a plurality of rotor bars inserted in the plurality of slots, and a plurality of holders arranged around a rotational axis of the rotor. Each holder comprises an insertion groove configured to receive and engage with an end of one of the plurality of rotor bars. An end of another rotor bar among the plurality of rotor bars is interposed between and coupled to two immediately neighboring holders among the plurality of holders.