Stator Thermal Insulation Channel for Motor Cooling

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Solution Overview

Problem

The existing electric motor design suffers from reduced efficiency in the secondary cooling circuit due to thermal interference from the primary cooling circuit, leading to overheating during high-power operation.

Innovation Solution

Incorporating a thermal insulation channel between the primary and secondary cooling circuits to act as a thermal barrier, reducing heat exchange and enhancing the cooling efficiency of the secondary circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the primary cooling channel is placed adjacent to the secondary cooling channel to cool the stator, then the stator cooling efficiency is improved, but heat exchanges between the primary and secondary cooling circuits increase, reducing the secondary cooling circuit efficiency

Engineering Contradiction:
Improvestator cooling efficiencyVSAvoidsecondary cooling circuit efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

A thermal insulation channel is introduced as an intermediary element between the primary cooling channel and the secondary cooling channel. This intermediary structure acts as a thermal barrier that prevents harmful heat transfer from the hot primary cooling channel to the cold secondary cooling channel, while allowing both cooling circuits to function in close proximity for effective stator cooling.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The wall structure of the stator is segmented into multiple functional zones: an outer wall portion for structural support, a primary cooling channel for stator cooling, a thermal insulation channel for heat isolation, and an inner wall portion adjacent to the secondary cooling channel. This segmentation allows each zone to perform its specific function without interfering with others.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the secondary cooling circuit is isolated from the exterior to prevent dust contamination, then the rotor protection is improved, but the cooling efficiency is reduced due to thermal interference from the primary cooling circuit

Engineering Contradiction:
Improve rotor protection from dustVSAvoidsecondary cooling circuit efficiency
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The thermal insulation channel serves as a mediator that enables the secondary cooling circuit to remain isolated from the exterior (maintaining dust protection) while still achieving effective cooling. By blocking heat transfer from the primary cooling channel, it allows the secondary cooling channel to maintain low temperatures without direct external communication.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Different parts of the stator wall structure are given different thermal properties: the thermal insulation channel portion has low thermal conductivity to block heat transfer, while the primary and secondary cooling channels have high thermal conductivity to facilitate heat exchange with the coolant. This local differentiation of thermal properties resolves the contradiction between isolation and cooling efficiency.

Inventive Principle:
Principle #3Local quality

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 increases the motor's lifespan and allows for higher power operation by minimizing heat transfer between the primary and secondary cooling circuits, thereby improving the cooling efficiency of the secondary circuit.

Implementation Method 1

a channel (40) of thermal insulation belonging to the secondary cooling circuit (30), said channel (40) being arranged between said primary cooling channel (26) and said second cooling channel (34) to form a thermal barrier between said primary cooling channel (26) and said second cooling channel (34)

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

a primary cooling circuit (20) for cooling said stator (16) by circulating ambient air in said primary cooling circuit (20)

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

a first cooling channel (32) extending parallel to the axis of rotation in said rotor (14) in which circulates a cold gaseous fluid to cool said rotor (14) by heat exchange

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3098949B1Stator comprising an integrated radiator
Publication Date: 2019.05.15 ALSTOM TRANSPORT TECH SAS
  • EP3098949B1 patent drawingFigure 1~2
  • EP3098949B1 patent drawingFigure 3~4
  • EP3098949B1 patent drawingFigure 5

AI summary

This electric motor (10) comprises a frame (12) defining an internal volume and including a rotor (14) and a stator (16), a primary cooling circuit (20) comprising at least one primary conduit (26) and in fluidic communication with the outside of the frame (12) to circulate a gas from outside the frame (12) into the internal volume of the frame (12), a secondary cooling circuit (30) extending into the internal volume of the frame (12) and insulated from the outside of the frame, said secondary cooling circuit comprising at least one first cooling channel (32) passing through the rotor (14) and at least one second cooling channel (34) passing through the stator (16), characterized in that it comprises at least one thermal insulation channel (40) interposed between the primary conduit (26) of the primary cooling circuit (20) and the second cooling channel (34) of the secondary cooling circuit (30).