Circuit Interrupter Actuator Control for Back Fed Configurations

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Solution Overview

Problem

Circuit interrupters in back fed configurations continue to energize the actuator even when disconnected due to persistent voltage on the load side, leading to unnecessary operation and potential failure.

Innovation Solution

A method and circuit interrupter design that detects fault conditions and determines current flow between the load side and separable contacts to control the actuator's operation, ensuring proper tripping by differentiating between open and closed states based on current flow rather than voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If voltage sensing is used to determine breaker state, then the method works for forward fed configurations, but it fails in back fed configurations where voltage remains on the load side after tripping

Engineering Contradiction:

Improvecompatibility with back fed configurationVSAvoidaccurate state detection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the detection parameter from voltage to current. By sensing current flow between the load side and separable contacts, the system can reliably determine breaker state in both forward fed and back fed configurations, eliminating the voltage sensing limitation in back fed applications

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the actuator continues to fire in back fed configuration after tripping, then the voltage sensing method is simple, but it causes unnecessary operation and potential actuator failure

Engineering Contradiction:

Improvesimplicity of control methodVSAvoidactuator operational reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements current sensing feedback to monitor whether current is flowing between the load side and separable contacts. This feedback mechanism provides accurate information about the actual breaker state, allowing the control system to stop actuator firing when the breaker is tripped, even in back fed configurations where voltage sensing would fail

Inventive Principle:

Principle #23Feedback

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

Effectively prevents continuous actuator firing when the circuit interrupter is tripped, ensuring safe and reliable operation in back fed configurations by accurately determining the state of separable contacts through current sensing.

Implementation Method 1

an actuator, such as a solenoid, operatively coupled to the separable contacts

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9036318B2Method of tripping a circuit interrupter in a back fed configuration

Publication Date: 2015.05.19 EATON INTELLIGENT POWER LTD

AI summary

A method of tripping a circuit interrupter in a back fed configuration is provided, wherein the circuit interrupter has separable contacts and an actuator, such as a solenoid, operatively coupled to the separable contacts. The method includes detecting within the circuit interrupter that a fault condition exists, and subsequent to detecting that the fault condition exists, determining whether a current is flowing within the circuit interrupter between a load side of the circuit interrupter and the separable contacts, and controlling operation of the actuator based on whether the current is flowing within the circuit interrupter.