Stator Coolant Passage Sealing During Vacuum Pressure Impregnation

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Solution Overview

Problem

The buildup of heat in rotor and stator components of electric machines due to disrupted or damaged internal coolant passages during the application of insulating varnish/resin, and the risk of foreign object debris in the cooling system, limits the power output of electric machines.

Innovation Solution

The implementation of a coolant passage seal, such as an extended core end ring, sealing plug, or threaded sealing plug, to protect coolant passages during the vacuum pressure impregnation process, ensuring the passages remain intact and debris-free.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If coolant passages are opened during the VPI process to allow resin penetration, then the insulating varnish/resin can penetrate and encapsulate the stator effectively, but the coolant passages may be disrupted or damaged and blocked by foreign object debris

Engineering Contradiction:

Improvecoolant passage integrityVSAvoidVPI process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Coolant passage seals are installed in the coolant passages before the VPI process begins. These seals pre-protect the passages from resin penetration and debris contamination during manufacturing, allowing the VPI process to proceed without special complexity while maintaining passage integrity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The coolant passage seals act as intermediary elements between the coolant passages and the insulating varnish/resin. They temporarily block the passages during VPI to prevent resin intrusion and debris contamination, then are removed afterward to restore full coolant flow capability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the stator is sealed during VPI to prevent resin penetration, then coolant passages remain protected, but the vacuum and pressure cannot effectively force resin to penetrate within the stator

Engineering Contradiction:

Improvecoolant passage protectionVSAvoidresin penetration effectiveness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The stator is segmented into multiple zones during VPI: sealed zones (coolant passages with seals) that remain protected, and unsealed zones (winding spaces) that allow effective resin penetration. This segmentation enables both protection and impregnation to occur simultaneously during the same process cycle

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If coolant passages are left open during manufacturing, then the VPI process can proceed without additional components, but foreign object debris may contaminate the cooling system

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddebris contamination

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

Disposable coolant passage seals are used that are installed before VPI and removed afterward. These temporary, low-cost components effectively prevent debris contamination during manufacturing, then are discarded after serving their protective purpose, leaving no permanent complexity in the final product

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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

The coolant passage seals effectively maintain the integrity and functionality of internal coolant passages, enhancing heat transfer and preventing debris, thereby improving the power output and efficiency of electric machines.

Implementation Method 1

a vacuum pressure impregnation (VPI) process applies an insulating varnish and/or resin to the stator. During the VPI process, the varnish/resin is applied in a liquid form and a vacuum is applied to force the varnish/resin to penetrate and encapsulate the stator

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

A pressurization process and a thermal curing process then may be used to cure the insulating varnish/resin. Both vacuum and pressure help the resin to penetrate within the stator

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 3

A pressurization process and a thermal curing process then may be used to cure the insulating varnish/resin

Methodology Applied

Scientific EffectThermal curing: Heating

Data Source

PatentUS20250279681A1Integrated sealing for internal cooling passages of electric machine laminated cores

Publication Date: 2025.09.04 GE INFRASTRUCTURE TECH LLC

AI summary

The present application provides a stator suitable for an application of an insulating varnish or resin in a vacuum pressure impregnation process. The stator includes a number of conductive windings and a coolant passage extending through the stator. The coolant passage is sealed via a coolant passage seal.