Residual Current Device Housing Partition Nesting
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Solution Overview
Problem
The challenge is to create a compact, mains voltage-independent residual current protective switching device with a summation current transformer that achieves high reliability while reducing assembly and manufacturing costs, particularly in limited installation spaces where existing devices are cumbersome and costly to assemble.
Innovation Solution
The device features an insulating material housing with separate current path areas, using high-temperature-resistant joints for critical connections and non-high-temperature-resistant joints for less thermally stressed areas, allowing for pre-assembly outside the housing and reducing heat input into the housing, thus enabling efficient assembly and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large summation current transformer is used for mains voltage-independent tripping, then reliability is improved, but device volume increases
Solution Approach 1:
The summation current transformer is nested within the housing partition opening, with the magnetic core positioned to receive primary conductors through its center. This nesting arrangement allows the transformer to be compactly integrated into the device structure without requiring additional external space, thereby maintaining small device volume while ensuring reliable mains voltage-independent tripping functionality.
2Reliability
If high-temperature-resistant joints are used for critical connections, then connection reliability is improved, but heat input into the housing increases
Solution Approach 1:
The patent applies different joint types to different locations based on thermal requirements: high-temperature-resistant joints (welding or brazing) are used specifically for the first primary conductor connection to the thermal tripping device where thermal stability is critical, while non-high-temperature-resistant joints are used for other connections where extreme heat resistance is not required. This localized application of quality ensures connection reliability at critical points while minimizing overall heat input into the housing.
Solution Approach 2:
The first primary conductor is pre-connected to the thermal tripping device using a high-temperature-resistant joint before final assembly into the housing. This preliminary action allows the critical thermal connection to be established with proper quality control before the conductor is inserted through the housing partition, thereby ensuring connection reliability while allowing the housing assembly to be completed at lower temperatures.
3Ease of manufacture
If assembly is performed outside the housing, then assembly effort is reduced, but assembly precision may worsen
Solution Approach 1:
The assembly process is segmented into distinct stages: first, the summation current transformer is pre-assembled with the first primary conductor and thermal tripping device outside the housing where adequate workspace allows for easier manipulation; second, this pre-assembled unit is inserted as a complete module through the housing partition opening; third, final connections are completed. This segmentation reduces overall assembly effort by allowing complex operations to be performed in accessible locations while maintaining precision through modular assembly and standardized interface fittings.
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
This approach results in a reliable, compact residual current protective switching device with reduced assembly effort and costs, capable of handling high currents and integrating multiple functionalities within a small form factor, while minimizing damage to the housing and other components.
Implementation Method 1
a thermal tripping device to detect an overload condition
Implementation Method 2
a summation current transformer through which the two primary conductors are passed... determines the differential current by adding the electrical currents flowing in several, for example two to four, primary conductors
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
The mains voltage-independent residual current device (1) according to the invention has an insulating housing (2) with a first (8) and a second current path area (9), which are separated from each other by a housing partition (10). A first primary conductor (P), which is part of a first current path (11), is arranged in the first current path area (8). A second primary conductor (N), which is part of a second current path (12), is arranged in the second current path area (9). Furthermore, the protective device (1) has a summation current transformer (21) which is received in an opening (13) of the housing partition (10), wherein the first primary conductor (P) and the second primary conductor (N) are passed through the summation current transformer (21). A first end (P1) of the first primary conductor (P) is electrically connected to a first contacting element (27) of the protective switching device (1) assigned to this end by means of a high-temperature resistant joining connection.Furthermore, a first (N1) and a second end (N2) of the second primary conductor (N) are electrically connected to a contacting element (16, 17) of the protective switching device (1) assigned to the respective end by means of non-high-temperature-resistant joining connections. Thermally highly stressed components can thus be joined outside the insulating housing (2) with thermally stable, high-temperature-resistant joining connections and only subsequently mounted in the insulating housing (2) in order to avoid damage and to ensure high reliability of the joining connection - and thus of the protective switching device (1).