Movable Contactor Assembly With Flexible Busbar for Arc Control
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Solution Overview
Problem
High power electrical contactors experience issues such as electrical arcing, oxidation of contact surfaces, and high contact resistance, leading to failure, as well as undesirable vibrations and noise due to magnetic forces causing movable contacts to separate from fixed contacts in high power applications.
Innovation Solution
A contactor design featuring a housing with a movable contact that engages multiple mating tab pads to create multiple electrical paths, a flexible busbar for permanent connection, and a coil assembly to move the contact between mated and unmated positions, reducing separation and vibration risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a movable contact is used to close electrical circuits in high power applications, then power transmission capability is improved, but electrical arcing and oxidation of contact surfaces occur leading to contactor failure
Solution Approach 1:
The movable contact is segmented into multiple contact elements (first movable contact element, second movable contact element, third movable contact element) that engage with corresponding fixed contact elements. This segmentation distributes the electrical current across multiple contact points, reducing the electrical stress and arcing at each individual contact interface, thereby improving reliability while maintaining high power transmission capability
Solution Approach 2:
A flexible busbar is introduced as an intermediary component that provides a permanent electrical connection between the first fixed contact element and the first movable contact element. This flexible busbar acts as a mediator that maintains continuous electrical connectivity even when the movable contact elements are in the open position, eliminating arcing at this interface and improving overall system reliability
2Speed
If magnetic forces are used to drive the movable contact, then electrical circuit closing speed is improved, but magnetic forces cause the movable contact to separate from fixed contacts leading to vibration and noise
Solution Approach 1:
The movable contact is divided into multiple segmented elements that are distributed across different locations. When magnetic forces act on these distributed elements, the forces are balanced more evenly, preventing excessive separation of any single contact element from its corresponding fixed contact element. This reduces vibration and noise while maintaining fast closing speed
Solution Approach 2:
Multiple movable contact elements and fixed contact elements are combined to work together as an integrated contact system. The flexible busbar merges the electrical connection paths, providing mechanical and electrical stability that counteracts the separating magnetic forces, thereby reducing vibration and noise during operation
3Reliability
If multiple contact elements are used to reduce arcing, then contactor reliability is improved, but device complexity increases
Solution Approach 1:
The flexible busbar serves multiple functions simultaneously: it provides a permanent electrical connection between fixed and movable contact elements, acts as a mechanical support structure, and accommodates the movement of contact elements during opening and closing operations. This multi-functionality reduces the need for additional separate components, thereby improving reliability without proportionally increasing device complexity
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 design effectively reduces arcing, oxidation, and contact resistance, while minimizing undesirable separations and vibrations, enhancing the reliability and performance of high power electrical contactors.
Implementation Method 1
When the contactor receives an electrical signal, the contactor is energized to introduce a magnetic field to drive a movable contact to mate with fixed contacts
Implementation Method 2
The flexible busbar electrically connects the first fixed contact and the movable contact in both the mated position and the unmated position
Data Source
AI summary
A contactor includes a housing and first and second fixed contacts coupling to the housing having mating ends received in the cavity of the housing and terminating ends outside of the housing. A movable contact is movable within the cavity between a mated position and an unmated position that engages the mating end of the second fixed contact in the mated position and is separated from the second fixed contact in the unmated position. A flexible busbar is coupled to the first mating end and coupled to the movable contact. The flexible busbar electrically connects the first fixed contact and the movable contact in both the mated position and the unmated position. A coil assembly in the cavity operates to move the movable contact between the unmated position and the mating position.