Short Circuit Rotor Electron Beam Welding Heat Management
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Solution Overview
Problem
Existing methods for producing squirrel-cage rotors face challenges such as heat input damage to the laminated core during welding, reduced strength and conductivity due to soldering, and inefficiencies in the welding process, particularly when using alloyed copper or aluminum discs.
Innovation Solution
A method involving a laminated rotor core with through openings for short-circuit bars, where the bars are inserted and axially overhanging main and continuous peripheral disks form a short-circuit ring, welded radially using electron beam welding, reducing heat input and allowing a single weld seam to join all components, thereby enhancing strength and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is performed directly on the laminated rotor core and short-circuit disk, then the electrical and mechanical properties are improved, but the heat input damages the insulation of the laminated core
Solution Approach 1:
The patent introduces a connecting disk as an intermediary component between the laminated rotor core and the short-circuit disk. The connecting disk serves as a mediator that receives the weld pool from the short-circuit disk without transmitting excessive heat to the laminated core, thus protecting the insulation while maintaining the electrical and mechanical properties of the assembly.
Solution Approach 2:
The patent divides the short-circuit ring assembly into multiple separate components: a connecting disk with recesses for cage bars, a short-circuit disk with through-openings, and the laminated rotor core. This segmentation allows the welding process to be performed on the connecting disk and short-circuit disk separately, controlling heat input and preventing damage to the laminated core insulation.
2Temperature
If alloyed copper or aluminum discs are used to increase speed capability and temperature resistance, then the temperature stability is improved, but the welding process reduces the strength and temperature stability properties
Solution Approach 1:
The patent applies different materials to different parts of the assembly: alloyed copper or aluminum discs are used specifically for the connecting disk and short-circuit disk where high temperature resistance is needed, while the laminated rotor core uses appropriate insulation materials. This local application of material properties allows the alloyed discs to provide temperature stability without requiring the entire assembly to withstand welding temperatures.
Solution Approach 2:
The connecting disk and short-circuit disk are prepared with precise recesses and through-openings before assembly, allowing the cage bars to be properly positioned and secured. This preliminary preparation ensures that the alloyed discs maintain their strength properties by avoiding excessive welding heat exposure during the assembly process.
3Ease of manufacture
If soldered connection is used between connecting disk and short-circuit disk, then the manufacturing complexity is reduced, but the strength and electrical conductivity are lowered
Solution Approach 1:
The patent replaces the soldered connection (chemical/joint process) with a welded connection (thermal/metallurgical process) between the connecting disk and short-circuit disk. This substitution eliminates the need for additional joining materials and produces a stronger, more electrically conductive bond while maintaining manufacturing efficiency through a single welding step.
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 approach reduces heat input into the rotor core, increases the strength and electrical conductivity of the connections, and simplifies the manufacturing process by using a single welding step without additional joining materials, resulting in a squirrel-cage rotor with improved torsional strength and conductivity.
Implementation Method 1
welding at least the main disk and the peripheral disk by means of radially circumferential electron beam welding
Implementation Method 2
welding at least the main disk and the peripheral disk by means of radially circumferential electron beam welding
Data Source
Figure 1~2
Figure 3
AI summary
Method for manufacturing a short-circuit rotor (1), comprising the following steps: - providing a rotor lamination stack (2) with through-holes for short-circuit bars (3) of a short-circuit cage and the short-circuit bars (3), - inserting the short-circuit bars (3) into the through-holes such that an axial projection remains on both sides, - placing a main disk (5) with through-holes (4) for the short-circuit bars (3), the axial length of which corresponds to the projection, and a continuous edge disk (6) directly adjoining the main disk (5) and the ends of the short-circuit bars (3), wherein the main disk (5) and the edge disk (6) form a short-circuit ring (7) of the short-circuit cage, - welding the main disk (5) and the edge disk (6) together by means of radially rotating electron beam welding.