Generator Rotor Sealing for High-Pressure Air Cooling

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Solution Overview

Problem

Existing generator rotors face challenges in achieving high current densities due to limitations in cooling methods, particularly with traditional air cooling, which restricts power density improvements.

Innovation Solution

The implementation of a high-pressure coolant system within the generator rotor, utilizing a rotor shaft with a rotor slot, wedge, and seal member to create an enclosed space for containing high-pressure coolant, along with multiple seals and retaining rings to maintain pressure and inhibit leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If traditional air cooling is used for rotor windings, then the structure is simple, but the current density and power density are limited

Engineering Contradiction:

Improvepower densityVSAvoidcooling system complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent applies hydraulic cooling by introducing a liquid coolant system with channels formed in the rotor core and windings. The coolant flows through these channels to directly remove heat from the windings, enabling higher current densities and power output compared to traditional air cooling methods

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the cooling medium from gas (air) to liquid (coolant), which fundamentally alters the heat transfer parameters. The liquid coolant provides superior thermal conductivity and heat capacity, allowing the system to operate at higher power densities while maintaining acceptable temperature levels

Inventive Principle:

Principle #35Parameter changes

2Temperature

If high-pressure coolant is introduced into the rotor, then cooling efficiency improves, but leakage risk increases

Engineering Contradiction:

Improvecooling efficiencyVSAvoidleakage prevention

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent segments the rotor cooling system into multiple independent channels and compartments. The rotor core is divided into sections with separate coolant passages, and sealing elements are placed at multiple locations to create isolated zones. This segmentation ensures that if one seal fails, the high-pressure coolant is contained within a limited section rather than causing complete system failure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent incorporates redundant sealing elements and pressure relief features as preventive measures. Multiple seals are installed in series along the coolant path, and the system design includes provisions for pressure equalization and fail-safe mechanisms that activate before catastrophic leakage can occur, cushioning against potential failure modes

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If rotor windings are directly cooled with high-pressure coolant, then current density increases, but manufacturing complexity increases

Engineering Contradiction:

Improvecurrent densityVSAvoidmanufacturing complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent integrates coolant channels directly within the rotor core structure and winding assembly. The cooling channels are formed as hollow passages within the rotor core laminations, and the windings are positioned around these channels. This nested arrangement eliminates the need for separate external cooling components and reduces the overall number of manufacturing steps

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent merges the structural rotor core, the cooling system, and the electrical winding support into a single integrated assembly. The rotor core serves dual functions as both the magnetic structure and the coolant conduit carrier, while the winding arrangement simultaneously provides electrical function and thermal management pathways, simplifying manufacturing compared to separate component assembly

Inventive Principle:

Principle #5Merging (Combining)

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 allows for direct cooling of the rotor windings with high-pressure coolant, enhancing power density and efficiency while reducing leakage, enabling higher field currents and improved machine operation.

Implementation Method 1

direct cooling of the rotor windings with high-pressure coolant

Methodology Applied

Scientific EffectDirect cooling: Cooling

Implementation Method 2

The seal member cooperates with the wedge and the rotor shaft to define a seal therebetween

Methodology Applied

Scientific EffectPressure containment: Pressure Increase

Data Source

PatentUS12537402B2Generator with high-pressure air cooling

Publication Date: 2026.01.27 SIEMENS ENERGY INC

AI summary

A generator rotor including a rotor shaft having a rotor slot includes a rotor winding at least partially disposed within the rotor slot and a wedge coupled to the rotor shaft and extending axially along the rotor shaft, the wedge positioned to inhibit radial movement of the rotor winding from the rotor slot. A seal member is coupled to the wedge and extends axially along the wedge. The seal member cooperates with the wedge and the rotor shaft to define a seal therebetween. The wedge, the seal member, and the rotor shaft cooperate to at least partially define an enclosed space operable to contain a high-pressure coolant.