Switching Device Instantaneous Release Mechanism for Fast Short Circuit Disconnection
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Solution Overview
Problem
Electromagnetic drives used in switching devices for motor starters have a large moving mass, resulting in long switch-off times that are inadequate for safely disconnecting short circuits, which can lead to arc re-ignition and contact welding.
Innovation Solution
A switching device with an instantaneous release mechanism, where the moving contact is rigidly coupled to an armature and pretensioned by a pressure spring, utilizing electrodynamic lifting forces to quickly separate from fixed contacts, and a holding device with a permanent magnetic system to maintain separation, ensuring safe disconnection and preventing re-ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic drives with large moving mass are used for operational switching, then the switching device can reliably close and open the current path, but the switch-off time becomes too long to safely disconnect short circuits
Solution Approach 1:
The switching device is segmented into two independent drive mechanisms: an electromagnetic drive for operational switching and an instantaneous release mechanism for emergency disconnection. This segmentation allows each mechanism to be optimized for its specific function, with the instantaneous release providing fast response for short circuit protection independent of the operational drive's switching time
Solution Approach 2:
The instantaneous release mechanism is pre-positioned and ready to act immediately upon detecting a short circuit condition. The moving contact is pre-loaded by a pressure spring against the fixed contact, and the instantaneous release can instantly overcome this preload to separate contacts, eliminating the need to wait for the electromagnetic drive to complete its switching cycle
2Reliability
If the moving contact is quickly separated from the fixed contact in the event of a short circuit, then arc re-ignition and contact welding are prevented, but the structure becomes more complex
Solution Approach 1:
The instantaneous release mechanism is merged with the existing electromagnetic drive structure. The armature of the instantaneous release is rigidly coupled to the moving contact, and the magnetic coil of the instantaneous release can be integrated with or positioned near the electromagnetic drive's magnetic coil, allowing shared structural elements and reducing overall device complexity
Solution Approach 2:
The pressure spring that pre-loads the moving contact against the fixed contact during normal operation automatically serves as the restoring force for the instantaneous release. When the instantaneous release activates, it overcomes this spring force to separate contacts, and when de-activated, the spring automatically returns the moving contact to its closed position, eliminating the need for separate resetting mechanisms
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
Enables quick and safe disconnection of short circuits and overloads, preventing arc re-ignition and contact welding, while maintaining a compact design and eliminating the need for separate mechanisms for resetting the quick release.
Implementation Method 1
the moving contact is pretensioned by a pressure spring
Implementation Method 2
a holding device with a permanent magnetic system to maintain separation
Implementation Method 3
utilizing electrodynamic lifting forces to quickly separate from fixed contacts
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
The invention relates to a switching device for the on-off switching of a current passing through a current path, having at least one fixed contact (11, 12) and at least one movable contact (14, 15), wherein the movable contact can be moved relative to the fixed contact for making or breaking the current path (10), and a drive (1) for the functional movement of a jumper (17) between a contact-making position and a contact-breaking position, wherein in the contact-making position with the fixed contact the movable contact (14, 15) makes the current path, and having a high-speed circuit breaker (2) for breaking the current path in the event of a short circuit or overload, wherein the armature (4) of the high-speed circuit breaker (2) is rigidly coupled to the movable contact (14, 15).