Squirrel Cage Split Short-Circuit Disk Design
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Solution Overview
Problem
Existing squirrel-cage rotors face challenges in achieving low electrical contact resistance between cage bars and short-circuit rings, and the production of these components is complex, requiring efficient mechanical and electrical connections.
Innovation Solution
A squirrel-cage design featuring a split structure with a thin connecting disk and a thicker short-circuit disk, where the cage bars are mechanically and electrically connected through recesses in the connecting disk and a planar contact with the short-circuit disk, utilizing materials like aluminum or copper for enhanced conductivity, and employing welding and soldering techniques for integral connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional short-circuit ring structure is used, then the mechanical connection is achieved, but the electrical contact resistance between cage bars and short-circuit ring remains high
Solution Approach 1:
The short-circuit ring is segmented into two distinct parts: a thin connecting disk for mechanical connection and a thick short-circuit disk for electrical conduction. This segmentation allows each part to be optimized for its specific function, reducing overall electrical contact resistance while maintaining manufacturability
Solution Approach 2:
The connecting disk and short-circuit disk are merged into a single integrated short-circuit ring structure through material connection (welding or bonding). This merging ensures low electrical contact resistance between cage bars and the short-circuit ring while maintaining structural integrity
2Reliability
If the short-circuit ring has sufficient material thickness for good electrical contact, then electrical conductivity is improved, but the production complexity and processing effort increase
Solution Approach 1:
The short-circuit ring is divided into two parts with different thicknesses: a thin connecting disk (1-5 mm) for easy mechanical processing and connection, and a thick short-circuit disk (10-30 mm) for optimal electrical conductivity. This segmentation resolves the contradiction by assigning different thickness requirements to different functional zones
Solution Approach 2:
Different regions of the short-circuit ring have different material thicknesses optimized for their specific functions. The connecting disk region has thin material for ease of manufacturing recesses and mechanical connection, while the short-circuit disk region has thick material for low electrical resistance, achieving local optimization
3Strength
If the connecting disk has large material thickness for mechanical strength, then structural integrity is improved, but the production complexity and processing effort increase
Solution Approach 1:
The connecting disk is separated as a distinct thin component (1-5 mm thickness) from the thick short-circuit disk. This segmentation allows the connecting disk to be easily manufactured with recesses for cage bars while providing sufficient mechanical strength for its specific connection function
Solution Approach 2:
The connecting disk region is locally optimized with thin material thickness sufficient for mechanical connection strength, while the short-circuit disk region has thick material for electrical conductivity. Each region has the minimum necessary thickness for its function, reducing overall production complexity
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 design reduces electrical contact resistance and simplifies the production process, allowing for efficient current flow and mechanical strength while optimizing space usage and weight reduction.
Implementation Method 1
the short-circuit disk and the connecting disk being in direct contact with one another in the axial direction, in particular in planar contact along a base area
Implementation Method 2
The integral connection between the cage bars and the connecting disk can be produced by means of a welded joint
Implementation Method 3
The integral connection between the connecting disk and the short-circuit disk is produced by means of a soldered joint
Data Source
Figure 1~2
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Figure 5~7
AI summary
The invention relates to a squirrel cage (100) for a squirrel-cage rotor. The squirrel cage comprises a plurality of cage bars (150), which extend in the axial direction (105) of the squirrel cage, a first cage ring (110A), and a second cage ring (110B), wherein the first cage ring (110A) and the second cage ring (110B) are arranged at ends (152A, 152B) of the plurality of cage bars (150) that are opposite each other in the axial direction. The squirrel cage is characterised in that at least one of the first cage ring (110A) and of the second cage ring (110B) comprises a connecting disc (120A, 120B) and a short-circuiting disc (130A, 130B). The connecting disc (120A, 120B) comprises a plurality of holes (122), in each of which a cage bar (150) is arranged, so that the plurality of cage bars is mechanically fixed in relation to the connecting disc (120A, 120B). The short-circuiting disc (130A, 130B) is in direct contact with the connecting disc (120A, 120B) in the axial direction (105).