Locomotive Power Contactor Nonmetallic Core Overheating

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Solution Overview

Problem

Conventional power contactors with ferromagnetic cores and magnetic amplifiers overheat when subjected to discontinuous current, leading to potential catastrophic failure due to induction and extreme temperatures in high-power locomotive applications.

Innovation Solution

A power contactor design featuring a blowout coil with helical turns of conductive material surrounding a nonmetallic core, eliminating metallic components that can induce overheating, and removing the magnetic amplifier and ferromagnetic core from existing contactors to prevent overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ferromagnetic core and magnetic amplifier are used in the power contactor, then the contactor can effectively manage continuous DC current, but the ferromagnetic core and metallic components overheat when subjected to discontinuous current due to magnetic flux induction

Engineering Contradiction:

Improvecontactor operation reliabilityVSAvoidferromagnetic core temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent removes the ferromagnetic core from the magnetic amplifier assembly, extracting the problematic metallic component that causes overheating under discontinuous current conditions. This leaves only the nonmetallic core structure, which does not experience magnetic flux induction and associated heating effects.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the material parameter of the core from ferromagnetic to nonmetallic. This fundamental material substitution eliminates the magnetic properties that cause induction heating when exposed to discontinuous or pulsed current, while maintaining the structural framework needed for the magnetic amplifier assembly.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a blowout coil with ferromagnetic core is used to extinguish arcs under load, then arc extinction is effective, but the ferromagnetic core and surrounding metallic components experience extreme temperatures that can lead to catastrophic failure

Engineering Contradiction:

Improvearc extinction effectivenessVSAvoidinduction heating effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of magnetic flux induction into a beneficial configuration by removing the ferromagnetic core. The nonmetallic core structure maintains the geometric framework needed for magnetic field generation while eliminating the harmful induction heating effect that occurs in ferromagnetic materials under discontinuous current.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Power

If conventional power contactors are used in pulse-width modulation switching systems, then the contactor can handle high current loads, but the discontinuous current causes induction heating in the ferromagnetic core and bolt assembly

Engineering Contradiction:

Improvecurrent handling capacityVSAvoidmetallic component temperature

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The patent extracts the ferromagnetic core from the contactor assembly, removing the component that experiences harmful induction heating. This modification allows the contactor to maintain its high current handling capability while operating in pulse-width modulation systems without the temperature problems associated with ferromagnetic materials.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a composite structure where the magnetic amplifier assembly uses a nonmetallic core instead of ferromagnetic material. This composite approach maintains the functional integrity of the magnetic amplifier while using materials that are immune to induction heating effects.

Inventive Principle:

Principle #40Composite materials

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 solution effectively mitigates overheating in power contactors, ensuring reliable operation under discontinuous current conditions by using a nonmetallic core that prevents magnetic flux induction, thus reducing the risk of component failure and maintaining power transmission circuit reliability.

Implementation Method 1

a blowout coil, one end of which may be connected to the stationary bus bar. The blowout coil may include a plurality of helical turns of conductive material surrounding a substantially nonmetallic core

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an arc chute for extinguishing an arc generated by opening the existing contactor under a current load

Methodology Applied

Scientific EffectElectric arc: Electric Arc

Data Source

PatentUS8933359B2Locomotive positive power bus contactor method of assembly

Publication Date: 2015.01.13 PROGRESS RAIL SERVICES CORP

AI summary

A method of manufacturing a power contactor from an existing contactor having a magnetic amplifier that comprises a blowout coil and a ferromagnetic core, and an arc chute for extinguishing an arc generated by opening the existing contactor under a current load is disclosed. The method includes removing a bolt assembly from the existing contactor and at least one side plate from the existing contactor. The method also includes removing the ferromagnetic core from the existing contactor.