Sealed Contactor Assembly With External Fuse for Arc Protection
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Solution Overview
Problem
Existing contactors for high-current circuits are large, heavy, and expensive, and suffer from arcing damage and explosion risks due to high-energy electric arcs, while smaller contactors cannot handle large currents effectively.
Innovation Solution
A contactor assembly with arc contacts and overcurrent protection devices outside the housing, featuring an actuator assembly that connects with arc contacts before carry contacts, and an external fuse for arc dissipation and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contactors are designed to withstand large currents, then they can handle high-current circuits, but they become large, heavy, and expensive to manufacture
Solution Approach 1:
The contactor is divided into separate functional components: arc contacts housed in a first housing, carry contacts housed in a second housing, and an external fuse positioned separately. This segmentation allows each component to be optimized independently, reducing the overall size and weight while maintaining current withstanding capability.
Solution Approach 2:
The fuse is extracted from the traditional integrated contactor design and positioned externally. This extraction removes the need for large internal arc dissipation structures, significantly reducing the contactor's size and weight while still providing protection against high currents through the external fuse.
2Weight of stationary object
If contactors are made smaller and lighter, then they are more compact and cheaper, but they cannot withstand large currents due to significant electrical arcs
Solution Approach 1:
Arc contacts serve as an intermediary element between the external fuse and the carry contacts. They provide a dedicated path for arc dissipation, allowing the compact contactor to handle large currents by directing arcs to the external fuse rather than requiring large internal arc suppression structures.
Solution Approach 2:
The design uses disposable arc contacts and an external fuse that can be replaced after experiencing high-current stress. This allows the main contactor body to remain small and lightweight while the sacrificial components absorb the stress of high currents, protecting the permanent structures.
3Volume of moving object
If contacts are positioned close together, then the contactor is more compact, but arcs can blow the contacts apart when current is interrupted
Solution Approach 1:
The arc dissipation function is extracted from the contactor interior and assigned to an external fuse. This allows contacts to be positioned close together for compactness while the external fuse handles arc dissipation, preventing arcs from blowing contacts apart.
Solution Approach 2:
Arc contacts act as an intermediary that intercepts arcs before they can affect the carry contacts. This mediation allows compact contact spacing while protecting the main contacts from arc damage through the arc contact-fuse pathway.
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 prevents arcing damage to carry contacts and explosion risks by directing arcs away from them, using an external fuse for easy replacement and preventing over-pressure, thus ensuring safe and reliable operation.
Implementation Method 1
An actuator assembly is provided in the interior compartment and is movable between an open position and a closed position. The actuator assembly has an electrical contact bridge configured to be in selective communication with the carry contacts and the arc contacts. As the actuator assembly is moved toward the closed position, the actuator assembly makes an electrical connection with the arc contacts prior to making an electrical connection with the current carry contacts.
Data Source
AI summary
An embodiment is directed to a contactor assembly which is adapted for switching power to a circuit having a power source. The contactor assembly includes a housing defining an interior compartment. Carry contacts and arc are positioned in the interior compartment of the housing. At least one arc contact has an overcurrent protection device positioned outside of the interior compartment of the housing. As an actuator assembly is moved toward the closed position, the actuator assembly makes an electrical connection with the arc contacts prior to making an electrical connection with the current carry contacts, and as the actuator assembly is moved toward the open position, the actuator assembly maintains an electrical connection with the arc contacts after breaking an electrical connection with the current carry contacts, prior to breaking the electrical connection with the arc contacts.