Rotating Electrical Machine Dual Fan Cooling System

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Solution Overview

Problem

Existing rotating electrical machines, particularly 'open' machines, face limitations in cooling efficiency due to restricted air circulation, which hampers convective exchanges between the rotor and stator.

Innovation Solution

The arrangement of two fans in series, with the first fan generating an axial airflow component that enhances convective exchanges by directing air towards the windings and the second fan creating a depression for improved air flow and heat exchange, while the air flows in channels between the stator and casing, increasing overall air flow and turbulence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a single fan or central air inlet is used, then the device complexity is reduced, but the cooling efficiency and convective exchanges are insufficient

Engineering Contradiction:
Improvecooling efficiencyVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The air inlet system is segmented into a central air inlet and multiple radial air inlets distributed around the circumference. This segmentation allows air to enter through multiple paths simultaneously, increasing overall air flow and cooling efficiency without requiring multiple fans, thus maintaining relatively simple device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-dimensional (central) air inlet to a multi-dimensional air inlet system by adding radial air inlets at different angular positions. This dimensional expansion enables air to enter from multiple directions, creating more comprehensive convective exchanges around the rotor and stator.

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

2Productivity

If air flow is increased through multiple fans, then convective exchanges improve, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveconvective exchangesVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The rotor's rotation itself generates centrifugal force that drives air circulation through the machine. The rotating rotor acts as its own fan, creating natural convection currents that cool both the rotor and stator without requiring external fan mechanisms, thereby maintaining device simplicity while achieving effective cooling.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention utilizes pneumatic principles by leveraging the centrifugal force generated by rotor rotation to move air through the machine. The rotating rotor creates pressure differentials that drive air flow through the stator and rotor channels, achieving cooling through fluid dynamics rather than mechanical fans.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Quantity of substance

If radial air inlets are added around the circumference, then air flow distribution improves, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveair flowVSAvoidmanufacturing precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The radial air inlets are distributed uniformly around the circumference of the machine, creating homogeneous air flow distribution. This uniform spacing ensures that air enters evenly from all radial directions, maximizing cooling efficiency while using standard manufacturing tolerances rather than requiring high-precision custom positioning.

Inventive Principle:
Principle #33Homogeneity

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 significantly enhances cooling efficiency by increasing air flow and convective exchanges, improving the performance of both the rotor and stator, and optimizing ventilation within the machine.

Implementation Method 1

The first fan is configured to generate a flow of air entering the machine and accelerate the speed of the air entering the machine

Methodology Applied
Scientific EffectAxial airflow generation:

Implementation Method 2

improve the convective exchanges at the level of the rotor or the stator, or even both

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The second fan, also called the main fan, can be configured to create a depression in the machine and generate an outgoing air flow

Methodology Applied
Scientific EffectDepression generation: Pressure Gradient

Implementation Method 4

the increase in the speed of the incoming air and the effects of centrifugation due to the rotation of the rotor can combine to make it possible to improve the flow of the air around the windings of the stator, and in particular to increase their turbulence

Methodology Applied
Scientific EffectCentrifugation: Centrifugal Force

Data Source

PatentEP2311172B1Rotating electrical machine
Publication Date: 2016.12.07 MOTEURS LEROY SOMER
  • EP2311172B1 patent drawingFigure 1~2
  • EP2311172B1 patent drawingFigure 3~4
  • EP2311172B1 patent drawingFigure 5~6

AI summary

The present invention relates to a rotating electrical machine comprising a rotor (10) rotating relative to a stator, the rotor rotatingly driving a first fan (40) placed at a first end of the stator and a second fan (50) placed at a second end of the stator opposite the first end, the first and second fans being configured to generate an air flow from the first fan to the second fan through the rotor and the stator, the first fan comprising an outer collar (42) connecting radial blade ends (43) therebetween.