Circuit Breaker Neutral Pole Transmission Mechanism

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Solution Overview

Problem

Existing four poles circuit breakers face challenges in securing electrical insulation of the neutral pole due to a shorter opening distance between the stationary and movable contactors, which compromises the fast closing and late opening characteristic.

Innovation Solution

The power transmission mechanism adjusts the length ratio of arms and links in the neutral pole to match or exceed those of other poles, ensuring an equal or greater opening distance and rotation angle, thereby maintaining sufficient insulation during both closing and opening operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the movable contactor of the neutral pole is disposed closer to the stationary contactor to achieve fast closing and late opening characteristic, then the closing speed is improved, but the electrical insulation is compromised due to shorter opening distance

Engineering Contradiction:
Improveclosing speedVSAvoidelectrical insulation
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the power transmission mechanism by setting the sum of arm length and link length in the neutral pole greater than that in other poles. This parameter adjustment allows the neutral pole movable contactor to have both faster closing speed and sufficient opening distance for electrical insulation, resolving the contradiction between closing speed and insulation reliability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the sum of arm length and link length in the neutral pole is made greater than in other poles, then the fast closing and late opening characteristic is achieved, but the structural complexity increases

Engineering Contradiction:
Improveswitching operation efficiencyVSAvoidmechanism structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by making only the neutral pole's power transmission mechanism different from other poles. Specifically, the sum of arm length and link length is increased only in the neutral pole, while other poles maintain identical structures. This localized modification achieves the desired switching characteristic without significantly increasing overall system complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2346063B1Power transmission mechanism for four poles circuit breaker
Publication Date: 2017.12.13 LG INDUSTRIAL SYSTEMS CO LTD
  • EP2346063B1 patent drawingFigure 1~2
  • EP2346063B1 patent drawingFigure 3~4

AI summary

Provided herein is a power transmission mechanism for a four poles circuit breaker in which the contacts of a neutral pole thereof are brought into contact earlier at the time of closing and separated later at the time of opening than those of the other poles thereof, and according to the present invention, there is disclosed a power transmission mechanism for a four poles circuit breaker comprising: a switching shaft (12) configured to provide a driving force for switching to the movable contactors of the poles; an arm (13a, 13b, 13c, 13d) provided to correspond to the four poles to transfer the rotational torque of the switching shaft; and a link (14b, 14d) configured to transfer the rotational torque of the arm to the movable contactor as a switching force, and provided to correspond to the four poles, wherein the sum of the length of the arm and the link in a neutral pole is longer than the sum of the length of the arm and the link in the poles excluding the neutral pole.