Magnetic Contactor State Detection for Stuck Contact Identification
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Solution Overview
Problem
Switching devices, particularly gas-filled power contactors, face challenges in safely disconnecting load circuits due to 'stuck' contacts, where welding occurs during switching, making it difficult to identify the switch position and respond to erroneous functions, especially in life-threatening voltage scenarios.
Innovation Solution
A switching device with a magnetic switch and permanent magnets is designed, where a normally-open reed switch is used to indicate the switching state, allowing for identification of a stuck contactor by monitoring the magnetic switch's state, ensuring safe disconnection and preventing unintended contact closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If parallel contacts (auxiliary contacts) are used to identify switching position, then switching state identification is improved, but device complexity increases due to hermetic sealing requirements
Solution Approach 1:
The patent extracts the switching state identification function from the hermetically sealed gas-filled contactor by using a separate magnetic field-based reed switch mechanism. This allows the main contacts to remain sealed while the reed switch, positioned externally or in a separate chamber, detects the armature position through magnetic field changes, thereby identifying the switching state without compromising the hermetic seal.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the armature movement and the switching state detection. The reed switch responds to magnetic field changes caused by permanent magnets attached to the armature, enabling non-contact transmission of switching state information from the sealed contactor interior to the external detection circuitry.
2Measurement precision
If a separate microswitch is used to identify switching position, then switching state identification is improved, but reliability deteriorates due to mechanical wear
Solution Approach 1:
The patent replaces the mechanical microswitch with a magnetic field-based reed switch system. Instead of using mechanical contacts that physically touch and wear, the reed switch detects the armature position through magnetic field changes, eliminating mechanical wear and significantly improving reliability while maintaining switching state identification capability.
3Measurement precision
If mechanical coupling is used to actuate microswitch, then switching state detection is improved, but device complexity increases due to additional mechanical components
Solution Approach 1:
The patent eliminates the need for mechanical coupling components by using magnetic field interaction between permanent magnets on the armature and the reed switch. This magnetic coupling replaces mechanical linkages, reducing device complexity while maintaining reliable switching state detection.
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 identifies the switching state and prevents stuck contacts by using a magnetic switch and permanent magnets, ensuring safe operation and reliable disconnection of load circuits, even in the presence of stray magnetic fields.
Implementation Method 1
A switching device with a magnetic switch and permanent magnets is designed, where a normally-open reed switch is used to indicate the switching state
Implementation Method 2
The switching device has at least one stationary contact and at least one movable contact... The movable contact can be moved in the switching device correspondingly between a non-switched-through state... and a switched-through state...
Data Source
AI summary
In an embodiment a switching device includes at least one stationary contact, a movable contact, an armature, a first permanent magnet, a second permanent magnet and a magnetic switch, wherein the movable contact is movable by the armature, wherein the first permanent magnet is attached to the armature, and wherein the second permanent magnet is arranged in a fixed position relative to the magnetic switch.