Electric Motor Cooling Circuits with Conical Channel

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Solution Overview

Problem

The existing electric motor design, with a secondary cooling circuit crossing the primary cooling circuit, hinders the cooling efficiency of the stator due to volume constraints, requiring interruptions to allow the secondary cooling circuit to pass, which limits the primary cooling circuit's volume and effectiveness.

Innovation Solution

The electric motor incorporates a primary cooling circuit with a channel of conical shape crossing the secondary cooling circuit, allowing increased volume for the primary cooling fluid and creating an additional heat exchange zone between external air and the secondary cooling circuit's fluid, while a radial fan enhances fluid flow in both circuits, maintaining efficient cooling without interrupting the primary circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the secondary cooling circuit is allowed to pass through the primary cooling circuit, then the rotor can be cooled, but the total volume of the primary cooling circuit must be limited which hinders cooling efficiency

Engineering Contradiction:
Improvecooling efficiencyVSAvoidvolume of primary cooling circuit
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The secondary cooling circuit is nested within the primary cooling circuit, with the secondary circuit passing through the stator structure. This allows the rotor to be cooled through the secondary circuit while the primary circuit maintains its cooling function through the stator, resolving the volume limitation issue by nesting one cooling system within another rather than requiring separate spatial volumes.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The cooling circuits are arranged in different spatial dimensions and paths. The primary cooling circuit flows through the stator windings, while the secondary cooling circuit passes through the stator structure itself. This dimensional separation allows both circuits to coexist without volume conflict, enabling the primary circuit to maintain adequate volume for efficient stator cooling.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the primary cooling circuit is interrupted to allow the secondary cooling circuit to pass, then the secondary circuit can be implemented, but the continuity and effectiveness of the primary cooling circuit is reduced

Engineering Contradiction:
Improvecooling circuit configurationVSAvoidcontinuity of primary cooling circuit
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The cooling system is segmented into two independent circuits: a primary cooling circuit for the stator and a secondary cooling circuit for the rotor. Each circuit operates independently with its own fluid path, allowing the secondary circuit to pass through the stator structure without interrupting the primary circuit's continuity. This segmentation enables both cooling functions to coexist without compromising reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stator structure serves as an intermediary medium that accommodates both cooling circuits. The secondary cooling circuit passes through the stator structure, which acts as a mediator allowing the secondary circuit to access the rotor while the primary circuit flows through the stator windings independently. This intermediary role of the stator structure enables both circuits to function simultaneously without interruption.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the total volume of the primary cooling circuit is limited, then the secondary cooling circuit can pass through, but the quantity of cooling gas is reduced

Engineering Contradiction:
Improvecooling circuit integrationVSAvoidquantity of cooling gas
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The secondary cooling circuit is nested within the primary cooling circuit's spatial arrangement, passing through the stator structure. This nesting allows the primary cooling circuit to maintain its full volume for adequate cooling gas quantity, while the secondary circuit utilizes the stator structure space to reach the rotor, eliminating the need to reduce primary circuit volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 design enhances the cooling efficiency of both the stator and rotor, allowing for increased power operation and longer motor life by increasing the primary cooling fluid volume and creating a secondary heat exchange zone, ensuring efficient and simple cooling without interrupting the primary circuit.

Implementation Method 1

a primary cooling circuit passing through the stator, comprising a primary inlet and a primary outlet in fluidic communication with the outside of the frame, a gaseous fluid from outside the frame entering through said primary inlet being intended to circulate in said primary cooling circuit and to exit said circuit through said primary outlet

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

at least one secondary cooling circuit, separate from the primary circuit, passing through the rotor and in fluidic communication with the secondary inlet and secondary outlet of the cooling device, a gaseous fluid internal to the secondary cooling circuit being intended to circulate in said secondary cooling circuit and in said external cooling device

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

the secondary circuit is connected to a cooling device extending outside the motor, allowing heat exchange between the gaseous fluid circulating in the closed loop of the secondary circuit and the outside air through the cooling device's wall

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

heat exchange occurs between the outside air circulating in the primary cooling circuit and the gaseous fluid circulating in the secondary cooling circuit at the point where the primary cooling circuit passes through the secondary cooling circuit

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3054568B1Electric motor with external radiator and two separate cooling circuits
Publication Date: 2021.04.21 ALSTOM TRANSPORT TECH SAS
  • EP3054568B1 patent drawingFigure 1~2

AI summary

This motor (10) comprises: - a frame (12) defining an internal volume in which a rotor (14) and a stator (16) are housed, - at least one cooling circuit (30), comprising a primary inlet (32) and a primary outlet (34) in fluidic communication with the exterior of the frame (12), - at least one cooling device (20) external to the frame (12) comprising a secondary air inlet (22) and a secondary air outlet (24), a duct (26), - at least one secondary cooling circuit (40), separate from the primary circuit (30), passing through the rotor (14) and in fluidic communication with the secondary inlet and secondary outlet of the cooling device (20). The secondary cooling circuit (40) is traversed by a channel (36) of the primary cooling circuit (30) supplying the stator (16) with the gaseous fluid from outside the frame (12).