Circuit Interrupter Contact Spring Mass for Welded Contact Opening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing circuit interrupters face challenges in efficiently opening welded or partially welded vacuum interrupters due to increased force requirements, which can lead to arcing and contact welding, necessitating improved mechanisms for quick and reliable fault clearance in power distribution systems.
Innovation Solution
A circuit interrupter device with a contact spring assembly featuring an annular mass and dielectric drive rod configuration, where the mass is positioned proximate to the vacuum interrupter to enhance the hammer-blow effect and reduce contact bounce, thereby minimizing weld formation and energy needed for opening, utilizing a spring and plunger mechanism within a solid insulation housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the mass of the insulating actuator rod or spring constant of the contact spring is increased to assist with opening welded contacts, then the force required to open welded contacts is reduced, but the device complexity and energy consumption increase
Solution Approach 1:
The patent applies local quality by positioning a mass specifically at the distal end of the actuator rod near the vacuum interrupter contacts, rather than uniformly increasing mass throughout the entire rod. This localized mass concentration provides the necessary hammer-blow effect exactly where needed to break welded contacts, while minimizing the overall mass increase and associated complexity of the actuator mechanism.
Solution Approach 2:
The patent changes the physical parameters of the contact spring assembly by introducing a dedicated mass component and optimizing the spring constant to work in conjunction with this mass. The spring is configured to accelerate the mass to generate sufficient impact force, representing a parameter change from static force application to dynamic impact force generation.
2Force
If the spring constant of the contact spring is increased to assist with opening welded contacts, then the force required to open welded contacts is reduced, but the energy consumption and device complexity increase
Solution Approach 1:
The patent employs periodic action through the oscillatory motion of the contact spring. The spring is compressed during contact closure and then releases this energy periodically during opening operations, using the stored elastic potential energy to drive the mass against the welded contacts. This periodic energy release is more efficient than continuous energy application.
Solution Approach 2:
The patent optimizes the spring constant parameter to achieve the right balance between stored energy and release characteristics. By carefully selecting the spring constant, the system maximizes the impact force generated during opening while minimizing the overall energy consumption of the actuation mechanism.
3Reliability
If a mass is positioned proximate to the vacuum interrupter to enhance the hammer-blow effect, then contact bounce is reduced and weld formation is minimized, but the device complexity increases
Solution Approach 1:
The patent merges the mass component with the actuator rod, integrating it as part of the existing actuation mechanism rather than adding a separate, independent component. The mass is attached to the distal end of the actuator rod, combining the functions of actuation and impact delivery into a single integrated assembly, thereby minimizing the increase in overall device complexity.
Solution Approach 2:
The mass serves multiple functions: it acts as both the actuator for opening the vacuum interrupter and the hammer-blow element for breaking welded contacts. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity while achieving the desired reliability improvement.
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 effectively reduces the force required to open welded contacts, enhances reliability, and minimizes arc duration and contact separation, leading to improved performance in fault interruption and restoration in power distribution systems.
Implementation Method 1
A circuit interrupter assembly includes a solid insulation housing, a vacuum interrupter, a mass, a plunger, a spring, and a dielectric drive rod. The mass is disposed within the first cavity... The plunger... is attached to the moving contact of the vacuum interrupter
Implementation Method 2
The spring is disposed within the inner bore between the plunger and the ferrule
Implementation Method 3
The dielectric drive rod is fastened to the ferrule... The plunger... engages with the mass in response to actuation of the dielectric drive rod
Data Source
AI summary
Devices and assemblies are provided for operating circuit interrupters. A circuit interrupter assembly includes a circuit interrupter and a contact spring assembly. The circuit interrupter is located within the housing and includes a moving contact and a stationary contact. Contact spring assembly includes a mass, a plunger, a ferrule, a spring, and a dielectric drive rod. The mass defines an inner bore with a first diameter at a first portion of the mass and a second diameter that is larger than the first diameter at a second portion of the mass. The plunger has a flange portion and a body portion. The flange portion is located within the inner bore at the second portion and has a flange diameter that is larger than the first diameter. The spring is disposed within the inner bore between the plunger and the ferrule.