DC Contactor Arc Management via Bridge Recesses
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Solution Overview
Problem
Existing contactors for bidirectional DC operation face issues with electric arcs during switching, leading to increased switching time, heat generation, and reduced service life due to arcs remaining at contact locations for long periods, especially when polarity is incorrect.
Innovation Solution
The contactor design includes a movable contact bridge with recesses between the guide and contacts, allowing arcs to escape and be deflected away from the guide using opposite polarity permanent magnets and deflection plates, ensuring arcs are directed towards quenching devices and preventing damage to the contact bridge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If permanent magnets with opposite polarity are used for bidirectional DC operation, then arcs are moved in the same direction regardless of polarity, but one arc is driven away from the quenching chamber causing it to remain in place too long
Solution Approach 1:
The contact bridge is segmented by introducing recesses that create separate zones: one for arcs driven towards the quenching chamber and another for arcs driven away. This segmentation allows each arc to be managed independently according to its movement direction, solving the problem of bidirectional operation where arcs behave differently based on current polarity.
Solution Approach 2:
Deflection plates are introduced as intermediary elements within the recesses to actively redirect arcs that would otherwise remain in harmful positions. These plates serve as mediators that change the trajectory of arcs driven away from the quenching chamber, guiding them towards safe extinction zones and preventing contact damage.
2Loss of time
If arcs remain at contact locations for long periods, then switching time increases and heat generation increases, but contactor service life is reduced due to burning off
Solution Approach 1:
The recesses extract arcs from the harmful contact region by providing alternative paths through openings in the contact bridge. arcs are taken out of the contact area and directed towards designated extinction zones, preventing prolonged contact with contact surfaces and reducing both switching time and contact wear.
Solution Approach 2:
The magnetic fields that initially drive arcs in potentially harmful directions are converted into beneficial forces by the recess structure. The same magnetic blowout effect that could drive arcs away from quenching chambers is now utilized to channel arcs through controlled paths in the recesses, where deflection plates guide them to safe extinction zones, transforming a potential harm into a beneficial arc management mechanism.
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 design effectively prevents arc-induced damage and prolongs the contactor's service life by ensuring arcs are extinguished in quenching chambers, regardless of current direction, reducing wear and heat generation.
Implementation Method 1
a magnet arrangement for generating electromagnetic force on electric arcs
Implementation Method 2
They each generate a magnetic field which, with a suitable polarity, exerts a force on the respective arc
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The invention relates to a contactor for DC operation, comprising a first contact (21) and a second contact (22), these contacts being in the form of fixed contacts, a third contact (31) and a fourth contact (32), a contact bridge (4) which supports the third and fourth contacts (31, 32), a guide (9) by means of which the contact bridge (4) can be mounted such that it can move along a movement direction, a magnet arrangement (5) for generating electromagnetic force on electric arcs (8) which are produced when the contacts (21, 22, 31, 32) are opened, wherein contact is established between a first pair of contacts, which comprises the first and the third contact (21, 31), and between a second pair of contacts, which comprises the second and the fourth contact (22, 32), in a closed position of the contact bridge (4). The invention is characterized in that the moving contact bridge (4) has at least one cutout (42) which is arranged between the guide (9) and the third contact (31), wherein the at least one cutout (42) is formed in such a way that an opening is provided in the contact bridge (4), it being possible for an arc (8) which is produced at the third contact (31) to pass through said opening in the direction of the movement direction of the contact bridge (4).