Tripping Unit Bimetal Adaptability AC DC Circuit Breakers

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Solution Overview

Problem

Multipolar circuit breakers are not cost-efficient in DC environments due to unnecessary tripping means being installed, as they are designed for AC conditions where all poles are under voltage, whereas in DC environments, only one pole has current, leading to inefficiency.

Innovation Solution

A tripping unit with bimetal strips connected in series to detect over-currents, allowing for mechanical actuation of the latching mechanism to switch off main contacts, which can be easily replaced to adapt to AC or DC environments, with optional bimetal strips for each pole in AC environments and bridge circuits to connect unused poles in series in DC environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multipolar circuit breakers are designed for AC conditions with all poles under voltage, then the circuit breaker can protect all main circuits in AC environments, but it becomes cost-inefficient in DC environments where only one pole has current

Engineering Contradiction:
Improveadaptability to different environments (AC/DC)VSAvoidcost efficiency
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The tripping unit is divided into separate, replaceable modules including bimetal strips for each pole. This segmentation allows users to install only the necessary components for their specific application (AC or DC environment), reducing manufacturing costs while maintaining versatility across different environments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circuit breaker system transitions from a static, fixed configuration to a dynamic, reconfigurable system where tripping units can be easily replaced or modified. This dynamic adaptability enables the same circuit breaker body to be optimized for different environments by changing only the tripping unit components.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple tripping means are installed in multipolar circuit breakers for AC environments, then all main circuits can be protected, but unnecessary components increase cost and complexity in DC environments

Engineering Contradiction:
Improveprotection coverageVSAvoidnumber of tripping means
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The unnecessary tripping means are extracted or removed from the system. In DC applications, only the required single bimetal strip is installed while the other tripping components are omitted, reducing device complexity and cost while maintaining adequate protection coverage for the specific application.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The circuit breaker body is designed as a universal platform that can accommodate different tripping unit configurations. The same circuit breaker housing and main structure serve both AC and DC applications, with only the tripping unit components varying based on the application requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If fixed tripping units are built into the circuit breaker, then the circuit breaker provides consistent protection, but it cannot be easily adapted to different AC or DC environments

Engineering Contradiction:
Improveenvironmental adaptabilityVSAvoidreplacement ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The tripping unit is segmented into separate, independently replaceable components including bimetal strips and associated mechanisms. This modular design enables easy removal and replacement of tripping units to adapt between AC and DC environments without affecting the main circuit breaker structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design allows for the discarding of obsolete or unnecessary tripping unit components and their replacement with appropriate components for the new application. The modular architecture facilitates straightforward recovery and reuse of the main circuit breaker body while replacing only the tripping unit portion.

Inventive Principle:
Principle #34Discarding and recovering

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

Enables efficient tripping of main contacts in both AC and DC environments by using bimetal strips to detect over-currents, reducing unnecessary components and allowing for easy adaptation and replacement, ensuring safety and efficiency.

Implementation Method 1

a bimetal strip which is connected in series to a main circuit of the circuit breaker and wherein the bimetal strip is operative connected with the latching mechanism

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the bimetal strip is operative connected with the latching mechanism... mechanically actuating a latching mechanism

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2395535B1Tripping unit for a circuit breaker
Publication Date: 2013.10.30 EATON ELECTRICAL IP
  • EP2395535B1 patent drawingFigure 1
  • EP2395535B1 patent drawingFigure 2
  • EP2395535B1 patent drawingFigure 3

AI summary

Tripping unit (2) for tripping the main contacts of main circuits of a multipolar circuit breaker (1) by mechanically actuating a latching mechanism (14) in the circuit breaker (1) when an over-current in at least one of the main circuits is detected, wherein the tripping unit (2) is pluggable connected to the circuit breaker (1) and comprising at least one bimetal strip (33a, 33b, 33c) which is connected in series to a main circuit of the circuit breaker (1) and wherein the bimetal strip (33a, 33b, 33c) is operative connected with the latching mechanism (14).