Spring-Loaded Switching Device for Surge Protection
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Solution Overview
Problem
Existing overvoltage protection devices are inadequate in handling high short-circuit currents, often leading to component destruction and fire hazards, as they require external fuses or mechanical switching devices to interrupt such currents, which may not respond effectively to currents between the milliampere and kiloampere range.
Innovation Solution
An overvoltage protection device comprising a thermally trippable, spring-loaded switching device connected in parallel with an overvoltage arrester, where the thermal tripping means is designed to release an unlocking slide in case of thermal overload, blocking the path of movement and ensuring safe short-circuiting without current flow through it, thus allowing external fuses to respond and maintaining a fail-safe condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external fuses or mechanical switching devices are used to interrupt short-circuit currents, then the short-circuit current can be interrupted, but the response time is delayed and the current may destroy components before the protective device responds
Solution Approach 1:
The patent combines the overvoltage protection function (varistor) and the short-circuit protection function (thermal release with spring-loaded switching device) into a single integrated structural unit. The thermal release means is arranged in the area where the overvoltage arrester heats up during overload, creating a direct thermal coupling that enables fast response without requiring separate external protective devices.
Solution Approach 2:
The thermal release means acts as an intermediary between the overvoltage arrester and the switching device. It converts the thermal energy generated by the arrester during overload into mechanical action that triggers the spring-loaded switching device, enabling automatic protection without external intervention.
2Speed
If the thermal tripping means is arranged opposite the overvoltage arrester with direct thermal coupling, then fast thermal response is achieved, but the switching device cannot handle high short-circuit currents in the kiloampere range
Solution Approach 1:
The patent segments the protection functions into two parts: the thermal release means handles the fast thermal response for overload detection, while the spring-loaded switching device handles the high-power short-circuit current interruption. This segmentation allows each component to be optimized for its specific function without compromise.
Solution Approach 2:
The switching device uses spring pre-tensioning to change the mechanical parameters of the system, enabling it to handle high short-circuit currents. The spring force provides the necessary operating energy for rapid contact opening under high current conditions, transforming the thermal-triggered mechanical system into a high-power switching capability.
3Power
If a fuse or mechanical switching device is required for DC voltage applications or short-circuit currents, then high current interruption is possible, but the device complexity increases and additional external components are needed
Solution Approach 1:
The integrated design makes the overvoltage protection device universally applicable to both AC and DC voltage applications. The spring-loaded switching device with thermal release can handle short-circuit currents in all operating conditions, eliminating the need for separate protective devices for different application types and reducing overall system 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 solution effectively handles high short-circuit currents by ensuring a fail-safe condition and preventing component destruction, as the switching device is designed to quickly respond to thermal overloads and isolate the short circuit, reducing the risk of fire hazards and ensuring reliable operation.
Implementation Method 1
the thermal tripping means being arranged in the area in which the overvoltage arrester is expected to heat up when it is overloaded
Implementation Method 2
spring-pretensioned
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a surge protection device, comprising at least one surge arrester and one short-circuit switching device which is connected in parallel with the surge arrester, can be thermally tripped and is spring-pretensioned, wherein the abovementioned means form one physical unit. The thermal tripping means is arranged in the region where heating of the surge arrester is expected when it is overloaded, and operating or surge current does not flow through said thermal tripping means. The thermal tripping means is in the form of a stop part which releases an unlocking slide of the switching device in the event of thermal overload. The switching device has two opposite contact pieces, wherein at least one of the contacts is of moveable design and is under spring pretension in the closing direction of the switching device. The opening state of the switching device is ensured by the unlocking slide and is released by the thermal tripping means for closing the switching device.