Unified Undervoltage Release for Multi-Size Circuit Breakers

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Solution Overview

Problem

The existing design of undervoltage (U/A) releases for circuit breakers requires multiple types due to varying nominal current capacities, leading to increased manufacturing effort and logistical complexity, as well as inefficient use of space in circuit breakers with lower current capacities where energy storage devices are not necessary.

Innovation Solution

A unified U/A release design for all sizes, where at least one size with higher current capacity includes an energy storage device consisting of a release lever, pawl lever, and tension spring, allowing the U/A release to provide sufficient tripping energy for all circuit breakers, with an additional release element for sizes without energy storage, ensuring consistent operation across the series.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different types of U/A releases are used for circuit breakers with different nominal current capacities, then the required tripping energy is met, but the manufacturing effort and logistical complexity increase

Engineering Contradiction:
Improvetripping energy sufficiencyVSAvoidnumber of U/A release types
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a single type of U/A release that can be used across all circuit breaker sizes in the series. The energy storage device is configured to provide sufficient tripping energy for both smaller circuit breakers (without energy storage) and larger circuit breakers (with energy storage), eliminating the need for multiple specialized U/A release types.

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

2Reliability

If an energy storage device is integrated into the U/A release, then the tripping energy is sufficient for high current capacity circuit breakers, but the installation space requirement increases

Engineering Contradiction:
Improvetripping energy sufficiencyVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent applies local quality by making the energy storage device selectively present only in larger circuit breaker sizes where higher tripping energy is required. Smaller circuit breaker sizes omit the energy storage device, optimizing their installation space while larger sizes include it to provide sufficient tripping energy.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the U/A release is de-energized before main contacts are closed, then remote tripping is enabled, but the release position timing must be precisely controlled

Engineering Contradiction:
Improveremote tripping capabilityVSAvoidrelease position timing
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by de-energizing the U/A release before the main contacts are closed during circuit breaker operation. This timing ensures that the release mechanism is prepared in advance for potential tripping events, enabling remote tripping capability while maintaining precise control over the release position sequence.

Inventive Principle:
Principle #10Preliminary action

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

This solution reduces the effort in producing and assembling individual parts, as the same U/A release can be used across all sizes, with the energy storage device providing sufficient tripping energy for both equipped and unequipped circuit breakers, optimizing manufacturing and space usage.

Implementation Method 1

an energy storage device, which consists of a release lever, a pawl lever and a tension spring tensioned between the two

Methodology Applied
Scientific EffectEnergy storage device: Mechanical Accumulator

Implementation Method 2

a tension spring tensioned between the two

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

An undervoltage release is an electromagnet that activates the tripping mechanism of the circuit breaker in the event of a voltage interruption

Methodology Applied
Scientific EffectElectromagnet: Electromagnet

Data Source

PatentEP2769399B1Range of multi-pole circuit breakers
Publication Date: 2015.08.19 EATON ELECTRICAL IP
  • EP2769399B1 patent drawingFigure 1~2
  • EP2769399B1 patent drawingFigure 3
  • EP2769399B1 patent drawingFigure 4~7

AI summary

The invention relates to a range of multi-pole circuit breakers of different sizes and different nominal current capacity. In order to reduce the cost in terms of deployable U/A tripping devices, a U/A tripping device (10) of the same type is provided for all sizes (1, 2, 3) of the range. For this purpose, at least one model size (3) of a higher rated current capacity is equipped with a power storage device (52), which is arranged in the functional chain between the trip plunger (16) of the U/A tripping device (10) and the lock pawl (43) of the latching mechanism (25). Furthermore, in the at least one model size (3) equipped with the energy storage device (52), a second release element (35) is connected to the latching mechanism (25) thereof, said second release element effecting the release of the U/A tripping device (10) during activation of the circuit breaker at an earlier stage than is the case in the other model groups (1, 2) using a first release element (34) connected to the latching mechanism (24) thereof.