Stator Cooling Layout With Parallel Passages for Lower Pressure Drop

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electrical machines face challenges in balancing pressure and thermal requirements for efficient stator cooling, particularly in large machines where uneven coolant distribution leads to high energy consumption and reduced thermal performance.

Innovation Solution

A stator design with parallel sets of passages for coolant flow, adjustable by inserts to balance pressure and thermal demands, using inserts to seal off specific circumferential locations for optimized coolant distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If liquid cooling is used to improve motor power density, then cooling performance is improved, but pressure drop increases and thermal performance remains insufficient

Engineering Contradiction:
Improvecooling performanceVSAvoidpressure drop
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The stator windings are divided into multiple circumferentially spaced sets, with each set having dedicated cooling passages. The flow channels are segmented into first and second circumferential channels that are axially spaced, creating multiple parallel cooling paths rather than a single flow path, thereby reducing pressure drop while maintaining cooling effectiveness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling system transitions from a single-plane cooling approach to a multi-dimensional approach by creating passages that extend axially through the stator windings and connecting first and second circumferential flow channels at different axial positions. This three-dimensional cooling network improves thermal performance while distributing pressure drop across multiple dimensions

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

2Power

If machine size increases to improve power output, then power density improves, but heat generation increases leading to overheating

Engineering Contradiction:
Improvepower densityVSAvoidheat generation
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The stator windings are segmented into multiple circumferentially spaced sets with dedicated cooling passages for each set. This segmentation allows heat from different regions to be removed independently through multiple parallel cooling paths, preventing heat accumulation and maintaining effective cooling as machine size and power output increase

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling system uses axial flow channels (first and second circumferential channels at different axial positions) connected by radial passages, creating a three-dimensional cooling network. This multi-dimensional approach increases the effective cooling surface area and heat transfer pathways, enabling better heat dissipation from larger, higher-power machines

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

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 reduces coolant pressure drop and enhances thermal performance by ensuring even coolant distribution across the stator, minimizing energy consumption while maintaining effective cooling.

Implementation Method 1

coolant flows through the first set of passages from the first circumferential flow channel to the second circumferential flow channel and then flows from the second circumferential flow channel through the second set of passages to the first circumferential flow channel

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

The stator being configured such that coolant flows through the first set of passages from the first circumferential flow channel to the second circumferential flow channel

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP4187758B1Stator for electrical machines
Publication Date: 2026.04.29 HAMILTON SUNDSTRAND CORP
  • EP4187758B1 patent drawingFigure 1
  • EP4187758B1 patent drawingFigure 2
  • EP4187758B1 patent drawingFigure 3

AI summary

A stator (2) for an electrical machine is provided. The stator comprises: an annular housing (22) extending around a central axis (X-X); a first circumferential flow channel (46) extending around the housing; a second circumferential flow channel (48) axially spaced from the first circumferential flow channel and extending around the housing; and a plurality of windings (8). The plurality of windings are circumferentially spaced about the housing to form a passage (50) between each two adjacent windings. Each passage is in fluid communication with both the first circumferential flow channel and the second circumferential flow channel. The first circumferential flow channel is closed to flow at a first circumferential location and the second circumferential flow channel is closed to flow at a second circumferential location, removed from the first circumferential location so as to form a first set of passages (S1) connected in parallel and a second, separate set of passages (S2) connected in parallel. The stator is configured such that coolant flows through the first set of passages from the first circumferential flow channel to the second circumferential flow channel and then flows from the second circumferential flow channel through the second set of passages to the first circumferential flow channel.