Welded Squirrel-Cage Rotor Bars for High-Speed Mechanical Stability
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Solution Overview
Problem
Squirrel cage rotor bars in asynchronous machines face deformation due to low mechanical strength and centrifugal forces at high speeds, requiring external support which increases costs and complexity.
Innovation Solution
The rotor bars are secured to the rotor body using a welded connection, specifically electron beam or laser beam welding, ensuring stable mechanical fixation against displacement and centrifugal forces, allowing for various material combinations and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rotor bars are made of materials with high electrical conductivity (copper, aluminum, steel), then resistance losses are kept low, but mechanical strength is reduced leading to deformation under centrifugal forces
Solution Approach 1:
The rotor bar uses a composite structure combining copper (high electrical conductivity) and steel (high mechanical strength). The copper core provides low resistance losses while the steel outer layer provides mechanical strength to resist centrifugal forces during high-speed rotation.
2Strength
If externally enclosing bandages are used to support rotor bars, then deformation is avoided, but cost and complexity of the asynchronous machine increase
Solution Approach 1:
The rotor bar combines multiple functions into a single integrated component: electrical conductivity for current flow, mechanical strength to resist centrifugal forces, and direct welding capability to the rotor body. This eliminates the need for separate external bandages and reduces structural complexity.
Solution Approach 2:
The mechanical support system is replaced by directly welding the rotor bar to the rotor body. The welded connection provides the necessary mechanical fixation and strength, eliminating the need for separate mechanical support structures like external bandages.
3Reliability
If rotor bars are traditionally supported by externally enclosing bandages, then deformation is prevented, but manufacturing cost and complexity increase
Solution Approach 1:
The mechanical support system is replaced by directly welding the rotor bar to the rotor body. The welded connection provides the necessary mechanical fixation and strength, eliminating the need for separate mechanical support structures like external bandages.
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 solution provides a stable mechanical fixation, preventing mechanical imbalance and ensuring safe operation, while enabling adaptable material usage and efficient production processes.
Implementation Method 1
connecting the rotor bars to the rotor body by a welded connection, in particular by an electron beam or laser beam weld
Implementation Method 2
connecting the rotor bars to the rotor body by a welded connection, in particular by an electron beam or laser beam weld
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to a rotor (1) of a squirrel-cage motor with a short-circuit cage, wherein rotor bars (2) of the short-circuit cage extend axially through a cylindrical rotor body (3), characterized in that the rotor bars (2) are connected to the rotor body (3) by a welded connection (4), in particular by an electron beam or laser beam welded connection.