Magnetic-Latching Contactor for Short-Circuit Arc Prevention
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Solution Overview
Problem
Existing electrical contactors face issues with catastrophic damage due to violent electrical arcing during short circuit fault conditions, as large currents generate Lorentz forces that separate the movable contact from stationary contacts, and increasing coil size to counter this is costly and inefficient.
Innovation Solution
Incorporation of magnetic latching elements within the contactor design, where induced magnetic flux strengthens the magnetic attraction between these elements, counteracting Lorentz forces and maintaining contact engagement during high current conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electromagnetic force generated by the coil is increased to prevent contact separation during short circuit, then the reliability is improved, but the device complexity and cost increase due to requiring a larger coil
Solution Approach 1:
A magnetic latching element is introduced as an intermediary component between the coil and the armature. This latching element maintains contact engagement during short circuit conditions through magnetic attraction, allowing the coil to be smaller while achieving the same reliability effect.
Solution Approach 2:
The patent replaces part of the electromagnetic force generation mechanism with a magnetic latching system. Instead of relying solely on the coil-generated electromagnetic force to maintain contact pressure, the magnetic latching element provides supplemental holding force, substituting mechanical magnetic attraction for additional electromagnetic force.
2Force
If a larger coil is used to increase electromagnetic force, then the force is improved, but the manufacturing cost increases
Solution Approach 1:
The magnetic latching element serves as a cost-effective intermediary that provides additional holding force without requiring a larger coil. This approach achieves the desired force improvement while avoiding the high cost of scaling up the coil.
Solution Approach 2:
The patent changes the system configuration by adding a magnetic latching element with specific magnetic properties, rather than simply increasing coil parameters. This alternative approach achieves force improvement through a different physical mechanism at lower cost.
3Reliability
If the coil size is increased to maintain contact engagement, then the reliability is improved, but the volume of the contactor increases
Solution Approach 1:
The magnetic latching element is a compact intermediary component that provides the necessary holding force without requiring significant additional volume. This allows reliability improvement while maintaining a compact contactor design.
Solution Approach 2:
The magnetic latching element is positioned within the existing contactor structure, nesting the additional functionality within the available space rather than requiring external expansion of the contactor volume.
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 magnetic latching elements effectively hold the movable contact in engagement with stationary contacts, preventing arcing and protecting the contactor and surrounding components from damage during short circuit faults.
Implementation Method 1
When the electromagnetic coil is energized, the electromagnetic coil generates a magnetic field around the core to produce an electromagnetic force that attracts the armature
Implementation Method 2
When electrical current flows through the movable contact between the first stationary contact and the second stationary contact, the electrical current induces a magnetic flux in the first magnetic latching element and the second magnetic latching element, whereby the first magnetic latching element and the second magnetic latching element are magnetized and are attracted to one another
Implementation Method 3
This deviation in the path of the current generates a magnetic flux which produces forces (commonly referred to as Lorentz forces) that act on the current and that tend to drive the movable contact and the stationary contacts away from each other
Data Source
AI summary
An electrical contactor including first and second stationary contacts, a movable contact disposed on a first end of a movable shaft that extends through a core and that is connected at a second end to an armature, an electromagnet coil surrounding the core, a first magnetic latching element disposed on the movable shaft, and a second magnetic latching element disposed adjacent the first and second stationary contacts, wherein, when the electromagnetic coil is energized, the core attracts the armature, thereby moving the movable shaft and bringing the movable contact into engagement with the first and second stationary contacts to allow electrical current to flow therebetween, wherein the electrical current induces a magnetic flux in the first and second magnetic latching elements, whereby the first and second magnetic latching elements are magnetized and are attracted to one another.