Movable Contactor Assembly for Current Limiting MCCB
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Solution Overview
Problem
The existing movable contactor assembly for large capacity current limiting type MCCBs has issues with electric power transmission efficiency due to high contact resistance, complex assembly processes, and increased fabrication costs, primarily because of the rigid components and numerous parts involved in the spring support mechanism.
Innovation Solution
A simplified movable contactor assembly with a terminal base, holder plates, first springs, extending plate portions, flexible wire plates, and second springs, which reduces the number of components and employs flexible materials to improve assembly productivity and power transmission efficiency, while being fabricated at a lower cost through pressing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid components and numerous parts are used in the spring support mechanism, then structural strength is improved, but device complexity and fabrication cost increase
Solution Approach 1:
The patent combines multiple rigid components (spring support pins, rollers, holder plates) into a single integrated pressing plate structure. The pressing plate incorporates spring mounting positions, support functions, and structural reinforcement elements that were previously separate parts, thereby reducing assembly complexity while maintaining structural strength through the unified design.
Solution Approach 2:
The pressing plate serves multiple functions simultaneously: it provides structural support, mounts springs, maintains contact pressure, and reinforces the terminal base. This multi-functional component replaces several specialized rigid parts, reducing device complexity while achieving the same structural strength through consolidated design.
2Strength
If rigid components are used in the spring support mechanism, then structural strength is improved, but manufacturing cost and fabrication time increase
Solution Approach 1:
By merging multiple rigid components into a single pressing plate, the patent reduces the number of parts that need to be manufactured, assembled, and quality-checked. This integration simplifies the manufacturing process, reduces material waste, and lowers fabrication costs while maintaining the required structural strength through the unified pressing plate design.
3Reliability
If numerous rigid parts are used in the assembly, then reliability is improved, but assembly productivity decreases
Solution Approach 1:
The integration of multiple rigid parts into a single pressing plate eliminates numerous assembly steps, fastening operations, and alignment procedures. This reduction in assembly complexity directly increases assembly productivity while the pressing plate maintains reliability by providing consistent structural support and spring mounting functionality that the original multiple components delivered.
4Reliability
If rigid components are used for electrical connection, then electrical conductivity is maintained, but contact resistance increases
Solution Approach 1:
The patent replaces rigid connection components with flexible wire plates that can elastically deform to maintain optimal contact pressure. This flexibility ensures consistent electrical contact with lower contact resistance compared to rigid components, while the spring-loaded mechanism maintains reliable electrical connection through continuous pressure application.
Solution Approach 2:
The patent changes the mechanical properties of the connection components from rigid to flexible, allowing the wire plates to deform and conform to contact surfaces. This parameter change enables better electrical contact with reduced contact resistance while maintaining connection reliability through the elastic properties of the flexible materials.
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 enhances electric power transmission efficiency by reducing contact resistance and simplifying the assembly process, thereby improving productivity and reducing fabrication time and costs.
Implementation Method 1
a plurality of first springs provided between the pair of holder plates, to provide an elastic force to the movable contactors in a direction in which the movable contactors are brought into contact with the fixed contactors when the molded case circuit breaker is in a closed circuit state
Implementation Method 2
providing an elastic force to the movable contactors in a direction in which the movable contactors are separated from the fixed contactor when the molded case circuit breaker performs a current limiting operation
Implementation Method 3
a second spring installed between the extending plate portions and the flexible wire plates to provide an elastic force to the flexible wire plates so as to be tightly contacted to the movable contactor
Implementation Method 4
a plurality of flexible wire plates having a portion fixedly connected to the terminal base and a portion extending between the movable contactors and the extending plate portions to electrically connect the movable contactors and the terminal base
Implementation Method 5
a movable contactor is separated from the fixed contactor by an electromagnetic repulsive force between the movable contactor and the fixed contactor whose currents flow in the opposite direction
Data Source
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AI summary
A movable contactor assembly for a current limiting type MCCB comprising: a terminal base (180) fixedly installed on a case of the MCCB; a plurality of movable contactors (110) having a cam face portion; a pair of holder plates (120) supporting the movable contactors at both sides thereof; a plurality of first springs (140) providing an elastic force to the movable contactors (100) in a direction in which the movable contactors (110) are brought into contact with the fixed contactors (1) when the MCCB is in a closed circuit state, and providing an elastic force to the movable contactors (110) in a direction in which the movable contactors (110) are separated from the fixed contactor (1) when the MCCB performs a current limiting operation; a plurality of extending plate portions (181,183,185) provided to face the side of one end portion of each of the movable contactors (110) so as to be electrically connected with the movable contactors (110); a plurality of flexible wire plates (170) electrically connecting the movable contactors (110) and the terminal base (180) and having a portion bendable toward the movable contactors (110) or toward the extending plate portions (181,183,185); and a second spring (PS1,PS2) providing an elastic force to the flexible wire plates (170) so as to be tightly attached to the movable contactor (110).