Relay Welding Detector Using Current Transformer

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Solution Overview

Problem

Existing relay welding detection methods, such as those using mechanical linkages, are costly and inefficient in disabling power transfer during welding faults, failing to meet safety requirements in regions like the U.S. and Europe.

Innovation Solution

A relay welding detector comprising a signal generator, current transformer, determining unit, and switch, which generates a test signal and determines welding faults by analyzing induced signals through current transformers wound around power lines, allowing for efficient detection of contact welding without mechanical linkages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical linkages are used to detect relay welding fault, then detection reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvewelding fault detection reliabilityVSAvoiddetection device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical linkage detection system with an electrical detection system using a current transformer. Instead of using mechanical components to detect welding faults, the invention uses electrical current measurement through the current transformer to sense contact welding conditions, thereby eliminating complex mechanical structures while maintaining detection reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a current transformer as an intermediary device to detect welding faults. The current transformer acts as a mediator that converts the electrical current information into detectable signals without requiring direct mechanical contact or complex linkages, simplifying the overall detection system

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If mechanical linkages are used to detect relay welding fault, then detection accuracy is improved, but manufacturing cost increases

Engineering Contradiction:
Improvewelding fault detection accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive mechanical linkage systems with a more cost-effective electrical detection system using a current transformer. This substitution maintains detection accuracy while significantly reducing manufacturing costs and improving ease of production

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a current transformer that is relatively simple and cost-effective compared to mechanical linkage systems. The electrical detection components are more economical to manufacture and replace, reducing overall system cost while maintaining functional effectiveness

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If mechanical linkages are used to detect relay welding fault, then safety compliance is improved, but device complexity increases

Engineering Contradiction:
Improvesafety complianceVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent achieves safety compliance through an electrical detection system using a current transformer, eliminating the need for complex mechanical linkages. The electrical-based detection method meets safety requirements while presenting a simpler, more maintainable system architecture

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If electrical detection method is used, then device complexity is reduced, but measurement precision may be affected

Engineering Contradiction:
Improvedetection device complexityVSAvoidwelding fault detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses a current transformer as an intermediary device that accurately captures electrical current characteristics to detect welding faults. This intermediary component ensures that the simplified electrical detection system maintains measurement precision by effectively transforming and measuring the relevant electrical parameters

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides a cost-effective and efficient method to detect welding faults, reducing operational costs and ensuring compliance with safety standards by simplifying the detection process.

Implementation Method 1

a current transformer (722), and a determining unit (723). The current transformer (722) is coupled to the signal generator (721), and is adapted to be wound with a portion of the first power line (91) by one turn or by multiple turns

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2879152B1Relay welding detector, relay equipment incorporating the same, and relay welding detecting method
Publication Date: 2018.06.27 LITE ON TECH CORP
  • EP2879152B1 patent drawingFigure 1
  • EP2879152B1 patent drawingFigure 2
  • EP2879152B1 patent drawingFigure 3

AI summary

A relay welding detector (72) is adapted for detecting welding fault of a relay (71). The relay (71) has a first electrical contact (711) coupled to a neutral terminal (N) of an alternating current (AC) power source (6) through a first power line (91), and a second electrical contact (712) coupled to a load (8) through a second power line (92). The relay welding detector (72) includes a signal generator (721) generating a test signal, a current transformer (722) wound with a portion of one of the power lines (91, 92) and generating an induced signal based on the test signal, and a determining unit (723) determining, based on the induced signal, whether the electrical contacts (711, 712) of the relay (71) are welded to each other.