Welding Copper Damper Bars in Permanent Magnet Synchronous Machines
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Solution Overview
Problem
In permanent magnet synchronous machines, direct welding of copper short-circuiting rings and bars for damper windings poses a risk of overheating and damaging the permanent magnets due to heat conduction, as traditional welding methods require significant heat input.
Innovation Solution
A blocking structure, such as a sleeve-type framing or ring-type groove, is used to limit heat flux during welding, concentrating heat precisely at the weld area and minimizing heat transfer to the magnets, while a massive iron short-circuiting and cooling system reduces magnetic flux and absorbs heat, allowing for faster and lower-heat welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If welding is used to join the copper short-circuiting ring and copper bar, then the jointing speed increases and heat input time decreases, but the concentrated heat may still damage the permanent magnets
Solution Approach 1:
The short-circuiting ring is segmented by introducing a blocking structure (such as a blocking groove or blocking protrusion) that divides the ring into separate thermal zones. This segmentation prevents heat from freely conducting to the permanent magnets while allowing the welding process to proceed quickly at the joint location.
Solution Approach 2:
The blocking structure acts as an intermediary element between the welding heat source and the permanent magnets. It intercepts and blocks the heat flux, preventing direct thermal coupling between the weld zone and the temperature-sensitive permanent magnets, thereby enabling fast welding without magnet damage.
2Object-affected harmful factors
If soldering is used to join the copper short-circuiting ring and copper bar, then the permanent magnets are protected from heat damage, but the jointing process becomes time-consuming and less efficient
Solution Approach 1:
By segmenting the short-circuiting ring with a blocking structure, the patent creates a thermal barrier that allows welding (a fast process) to be used instead of soldering (a slow process), while still protecting the permanent magnets from excessive heat.
Solution Approach 2:
The blocking structure changes the thermal parameters of the system by introducing a heat flux barrier. This allows the welding process parameters (higher heat input, shorter time) to be used without causing the same thermal damage that would occur in the traditional configuration, thereby improving productivity while maintaining magnet protection.
3Strength
If high heat input is applied to weld the copper parts, then the welding quality improves, but the permanent magnets are overheated and destroyed
Solution Approach 1:
The blocking structure serves as a thermal intermediary that allows high heat input to be applied at the weld zone to achieve high-quality welding, while simultaneously blocking the heat flux from reaching the permanent magnets, thus preventing their overheating and destruction.
Solution Approach 2:
The blocking structure segments the thermal field, creating a high-temperature zone at the weld joint for quality welding and a low-temperature zone at the permanent magnets for their protection, allowing high heat input without magnet damage.
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
Enables secure welding of copper short-circuiting rings and bars without damaging permanent magnets, facilitating faster and more efficient welding with reduced heat exposure, maintaining the integrity and temperature stability of the magnets.
Implementation Method 1
the blocking structure for limiting the heat flux during the manufacturing process from being conducted further to the short-circuiting ring from the weld between the short-circuiting ring and the bar
Implementation Method 2
the end of the bar is jointed to a hole disposed in the short-circuiting ring by welding them together at the mating surfaces
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a joint between a copper short-circuiting ring (1) and a copper bar (2) of the damper winding in a permanent magnet synchronous machine, wherein the end of the bar is jointed to a hole (9) disposed in the short-circuiting ring by welding them together at the mating surfaces. Further, the invention relates to a corresponding method. According to the invention the short-circuiting ring (1) includes a blocking structure for limiting the heat flux from being conducted further into the short-circuiting ring from the weld between the short-circuiting ring and the bar.