Electric Motor Cooling Circuit Segmentation

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Solution Overview

Problem

Existing electric motors with cooling circuits are not entirely satisfactory in terms of cooling efficiency for motor elements such as the stator and rotor, particularly in preventing dust contamination and achieving effective heat exchange.

Innovation Solution

The electric motor incorporates a primary and secondary cooling circuit with a heat exchanger, where the primary circuit uses external air for cooling the stator and the secondary circuit uses internal air, with a ventilation device for forced circulation and a tubular heat exchanger design that includes primary and secondary pipes for enhanced heat exchange, and the use of external fins for increased surface area heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a secondary cooling circuit is used to cool internal components, then cooling efficiency is improved, but dust contamination of internal motor components occurs

Engineering Contradiction:
Improvecooling efficiencyVSAvoiddust contamination
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The cooling system is segmented into a primary cooling circuit for the stator and a secondary cooling circuit for the rotor and other internal components. This segmentation allows the secondary circuit to remain closed and isolated from external dust while the primary circuit handles external air cooling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A heat exchanger acts as an intermediary between the primary and secondary cooling circuits. The heat exchanger enables thermal energy transfer from the secondary circuit's internal fluid to the primary circuit's external air without allowing direct fluid communication, thus preventing dust entry while maintaining cooling efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If external air is used for cooling, then heat dissipation is improved, but dust and contaminants enter the motor interior

Engineering Contradiction:
Improveheat dissipationVSAvoiddust and contaminants
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The cooling system is divided into external (primary) and internal (secondary) circuits. The primary circuit uses external air for heat dissipation while the secondary circuit remains sealed, preventing contaminant entry while maintaining effective cooling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heat exchanger serves as an intermediary that allows thermal energy to pass from the internal secondary circuit to the external primary circuit without allowing physical mixing of fluids or entry of contaminants into the motor interior.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If a closed secondary cooling circuit is used, then internal cleanliness is maintained, but cooling efficiency for rotor and stator is insufficient

Engineering Contradiction:
Improveinternal cleanlinessVSAvoidcooling efficiency
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The primary and secondary cooling circuits are merged through the heat exchanger to work together as an integrated cooling system. The secondary circuit maintains cleanliness while the primary circuit provides enhanced heat dissipation capacity, and their combination through thermal contact achieves both goals simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat exchanger mediates between the clean internal secondary circuit and the external primary circuit, allowing thermal energy transfer that enhances overall cooling efficiency while preserving the cleanliness benefits of the closed secondary circuit.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If separate primary and secondary cooling circuits are used, then component protection is improved, but heat exchange efficiency is reduced

Engineering Contradiction:
Improvecomponent protectionVSAvoidheat exchange efficiency
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The heat exchanger acts as an intermediary that enables efficient thermal energy transfer between the separate primary and secondary circuits. This intermediary structure allows the circuits to remain separate for component protection while achieving effective heat exchange through thermal contact between the circuits.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration improves the cooling efficiency of the motor elements by effectively transferring heat from the internal fluid to external air, maintaining internal cleanliness and enhancing thermal energy exchange, leading to improved performance and reduced dust contamination.

Implementation Method 1

The primary and secondary circuits pass, separated from each other, through the exchanger to allow heat exchange between the outside air and a fluid circulating in the secondary circuit

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the heat exchanger comprising at least one primary pipe and at least one secondary pipe in thermal contact with the primary pipe or pipes

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a ventilation device connected to the primary pipe or pipes to force the circulation of an external cooling fluid through the primary pipe or pipes between a suction inlet and at least one discharge outlet

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP3484026B1Electric motor comprising an exchanger and a plurality of cooling circuits
Publication Date: 2023.03.01 ALSTOM HOLDINGS SA
  • EP3484026B1 patent drawingFigure 1
  • EP3484026B1 patent drawingFigure 2
  • EP3484026B1 patent drawingFigure 3~5

AI summary

An electric motor (10) comprising: - a frame (12) defining an enclosed internal volume (13); - a rotor (14) and a stator (16) forming part of a magnetic circuit, the rotor (14) and the stator (16) being housed within the enclosed internal volume (13); - at least one heat exchanger (18) external to the frame (12), the heat exchanger (18) comprising at least one primary pipe (30) and at least one secondary pipe (32) in thermal contact with the primary pipe(s) (30); - a ventilation device (60) connected to the primary pipe(s) (30). The stator (16) includes at least one through-cooling pipe (52), and the motor (10) includes a diverter device between the suction inlet (50) and the discharge outlet (54, 56).