Stator Slot Cooling With Spacer-Formed Coolant Gaps
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Solution Overview
Problem
Existing cooling methods for electric machine stators are inefficient due to long heat conduction paths, high thermal resistance from insulating materials, and assembly tolerances creating air gaps, leading to high conductor temperatures and reduced efficiency.
Innovation Solution
A stator design with spacers maintaining a defined distance between electrical conductors and the laminated core, allowing coolant flow and improved heat transfer, combined with caps surrounding winding heads and a non-conductive fluid to enhance cooling, and a mechanically insulated stator-housing connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a water jacket surrounds the stator support, then the stator can be cooled, but the heat conduction path becomes relatively long and thermal resistance increases
Solution Approach 1:
The invention transitions from external cooling (water jacket surrounding stator support) to internal cooling (coolant flowing directly through slots in the laminated core). This dimensional change allows coolant to contact conductors directly, dramatically shortening the heat conduction path from conductors to coolant without requiring external jackets.
2Reliability
If electrical insulating material surrounds the conductors, then electrical insulation is provided, but thermal conductivity decreases significantly
Solution Approach 1:
The invention extracts and removes the electrical insulating material from between the conductors and the cooling path. By eliminating this thermal barrier, coolant can flow directly around conductors in the slots, providing both electrical insulation (through the laminated core structure) and efficient thermal conduction simultaneously.
3Ease of manufacture
If air gaps are created due to assembly tolerances, then clearance adjustments are achieved, but thermal insulation increases and cooling efficiency decreases
Solution Approach 1:
The invention utilizes the air gaps created by assembly tolerances as intentional coolant flow channels. The slots in the laminated core, which would normally be filled with insulating material or left as air gaps, are designed to accommodate coolant flow, transforming thermal insulation defects into functional cooling pathways.
4Temperature
If conductor temperature increases, then heat dissipation is reduced, but cooling system complexity increases
Solution Approach 1:
The invention merges the structural laminated core with the cooling function by integrating slots directly into the core structure. This combination allows coolant to flow through the core itself, providing direct cooling of conductors without requiring separate cooling components, thereby controlling temperature while minimizing system 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
Enhances cooling efficiency by reducing temperature gradients and maintaining efficient heat dissipation, improving conductor and core cooling, and extending material service life.
Implementation Method 1
a coolant flow path is provided in the slot between the electrical conductor and the laminated core
Implementation Method 2
heat from the electrical conductor can transfer across the entire conductor area in the slot into the coolant. Conversely, heat from the laminated core can also transfer across the entire slot area into the coolant
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
In a stator (1) of an electrical machine (200) a defined distance (22) between the electric conductor (2) of the windings and the laminated core (11) is ensured in grooves (12) of the stator (1) by means of a spacer (3, 4). The resulting spacing serves as a flow path for a coolant.