Conical Short-Circuit Contact for Bounce-Free Fast Closing
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Solution Overview
Problem
Existing short-circuiting devices for low and medium-voltage systems face challenges in achieving a compact design with high current-carrying capacity and extremely short closing times while minimizing contact bounce and arcing, which leads to increased construction and production costs and potential damage to contact surfaces.
Innovation Solution
A short-circuiting device with a movable contact part having a long, flat-angled cone-shaped contact area and a spring drive, where the kinetic energy is converted into plastic deformation to reduce bounce and arcing, and a sacrificial element is used between peg-shaped extensions to facilitate a bounce-free, plastically deformable contact area, along with a bridge igniter-based switching element for rapid activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a metallic short-circuit is implemented very quickly to protect against high currents, then the response time is reduced and protection effectiveness is improved, but contact bounce and arcing occur which damage contact surfaces and increase construction complexity
Solution Approach 1:
The patent converts the harmful effect of arcing into a beneficial plastic deformation process. The arc generated during contact closing is directed to melt and deform the sacrificial element and contact surfaces, creating a stable plastic bond that eliminates bounce. This transforms the damaging arc energy into a useful bonding mechanism that ensures reliable contact closure.
Solution Approach 2:
The sacrificial element is designed as a consumable component that is intentionally destroyed during the short-circuiting process. This disposable element absorbs the mechanical energy and facilitates the plastic deformation of contacts, enabling fast closing without bounce. The sacrificial nature of this component simplifies the overall device design by eliminating the need for complex bounce-damping mechanisms.
2Speed
If high spring force is used to reduce movement time and achieve faster response, then the closing speed is improved, but the mechanical strength requirements increase and contact bounce becomes more difficult to control
Solution Approach 1:
The patent changes the physical state of the contact materials through controlled heating and plastic deformation. By raising the temperature of the contact surfaces and sacrificial element through current flow and arc heating, the material parameters change to allow easier deformation and bonding at lower mechanical forces, reducing the required spring force while maintaining fast closing speed.
Solution Approach 2:
The patent utilizes phase transitions of the sacrificial element and contact materials during the short-circuiting process. The sacrificial element undergoes melting and vaporization phases when exposed to the arc, facilitating rapid material transfer and bonding. This phase change mechanism enables fast contact closure with reduced mechanical force requirements compared to purely solid-state deformation.
3Volume of moving object
If the contact electrodes are designed with high current-carrying capacity for compact design, then the device size is reduced, but the heat generation increases which can cause thermal deformation and affect reliability
Solution Approach 1:
The patent ensures continuous heat dissipation during the short-circuiting process by maintaining current flow through the plastic-deformed contact area. The sustained current creates continuous heating that maintains the plastic state of the contacts, preventing thermal shock and ensuring stable bonding. This continuous thermal action allows compact high-current design without thermal damage.
Solution Approach 2:
The patent employs composite material behavior where the contact surfaces and sacrificial element form a metallurgical bond through plastic deformation and melting. This composite structure combines materials with complementary properties - the sacrificial element provides low melting point for easy bonding, while the contact electrodes provide high current-carrying capacity. The resulting composite contact structure achieves both compact size and high thermal stability.
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 enables a compact, high-current-carrying capacity with reduced bounce and arcing, achieving faster closing times and maintaining current flow without surface damage, while reducing costs and complexity compared to semiconductor switches.
Implementation Method 1
a sacrificial element (6) as a spacer between the contact electrodes and with an electrical connection between the sacrificial element and the switching element on the one hand and one of the contact electrodes on the other hand, in order to bring about a current flow-related, thermal deformation or destruction of the sacrificial element in a targeted manner
Implementation Method 2
a movable contact part that is under mechanical prestress and, in the event of a short circuit, carries out a movement to the further contact electrode with the support of spring force
Implementation Method 3
a bridge igniter-based switching element for rapid activation
Data Source
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AI summary
The invention relates to a short-circuiting device for use in low-voltage and medium-voltage systems for the protection of property and persons, comprising: a switching element, which can be operated by the tripping signal of a fault detection device; two mutually opposite contact electrodes having power supply means, which contact electrodes can be brought into contact with an electrical circuit having connection points at different potential; furthermore, in at least one of the contact electrodes, a movable contact part, which is under mechanical preload and executes a movement to the further contact electrode with the assistance of spring force in the event of a short circuit; and a sacrificial element as a spacer between the contact electrodes, with an electrical connection between the sacrificial element and the switching element on the one hand and one of the contact electrodes on the other hand, in order to deliberately cause current-flow-induced thermal deformation or destruction of the sacrificial element. According to the invention, the movable contact part is in the form of a hollow cylinder which is closed on one side, and a spring for generating preload is inserted in the hollow cylinder. The hollow cylinder is movably guided in a complementary cutout in the first contact electrode, a sliding contact thus being formed. In the region of the base of the closed hollow cylinder, the cylinder wall of said hollow cylinder transitions into a cone at the outer circumference. Furthermore, a first pin-like extension, opposite to which a second pin-like extension insulated from the contact electrodes is situated, extends within the hollow cylinder, proceeding from the base. The sacrificial element, in the form of a bolt or screw, is arranged between the first and the second pin-like extension. A cutout, which has an internal cone and is matched to the external cone of the movable contact, is provided in the second contact electrode. The external cone and the internal cone form a bounce-free short-circuit contact region having frictional locking and interlocking connection on account of plastic deformation which occurs. Furthermore, according to the invention the switching element is designed as an auxiliary short-circuiter on the basis of an electric match.