Electromagnetic Contactor Lorentz Force Contact Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electromagnetic contactors face challenges in preventing movable contacts from opening due to electromagnetic repulsion forces during high current conditions, particularly when combined with fuses or circuit breakers, as they require increased contact spring force and electromagnet thrust, leading to larger configurations and vulnerability to external magnetic fields.
Innovation Solution
The electromagnetic contactor is designed with fixed and movable contacts shaped to generate Lorentz forces opposing electromagnetic repulsion forces, and external connection conductors are oriented to cross the current flow direction, enhancing magnetic flux density and shielding effects to prevent opening, thus reducing the need for mechanical pressing forces and minimizing overall size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact pressure generated by the contact spring is increased to prevent movable contact opening, then the reliability is improved, but the device complexity and size are increased
Solution Approach 1:
The patent converts the harmful electromagnetic repulsion force into a beneficial effect by shaping the fixed and movable contacts to generate Lorentz forces that oppose the repulsion. The contacts are formed with specific geometries (such as L-shapes or U-shapes) that create magnetic fields interacting with the current to produce closing forces that prevent contact opening during high current conduction
Solution Approach 2:
The patent changes the geometric parameters of the contact shapes to optimize the generation of Lorentz forces. By adjusting the shape configuration, contact area, and orientation of the contacts, the magnetic field distribution and resulting Lorentz forces are optimized to provide sufficient closing force without requiring increased mechanical spring pressure
2Reliability
If the spring force of the contact spring is increased to secure contact pressure, then the reliability is improved, but the size of the overall configuration is increased
Solution Approach 1:
The harmful electromagnetic repulsion force is converted into a beneficial closing force through properly shaped contacts that generate Lorentz forces. This eliminates the need to increase spring force, thereby avoiding the associated increase in device size
Solution Approach 2:
The patent replaces the mechanical spring force system with an electromagnetic Lorentz force system. Instead of relying on mechanical pressing forces from springs, the contact closing force is generated through the interaction of magnetic fields and current in the shaped contacts, reducing mechanical component size
3Productivity
If the electromagnetic repulsion force is increased to enhance opening speed during fault, then the productivity is improved, but the reliability is worsened due to contact opening during normal operation
Solution Approach 1:
The patent applies different functional qualities to different parts of the contact system. The contact shapes are specifically designed to generate Lorentz forces localized at the contact interface during normal operation to prevent opening, while the overall contactor structure maintains the capability for rapid opening during faults through the electromagnet actuation system
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 configuration effectively suppresses electromagnetic repulsion forces without increasing the device's size, ensuring reliable operation and reduced thrust requirements, while shielding magnetic fields from external conductors maintains strong Lorentz forces, preventing movable contact opening during high currents.
Implementation Method 1
at least either the fixed contacts or movable contact is formed in a shape such as to form magnetic fields generating Lorentz forces opposing electromagnetic repulsion forces generated in an opening direction between the fixed contact portions and the movable contact portions when current is conducted
Implementation Method 2
an electromagnetic coil 8, wound in a coil holder 7... supplied with a single-phase alternating current... generate electromagnetic repulsion forces
Data Source
AI summary
An electromagnetic contactor includes a contact mechanism including a pair of fixed contacts having fixed contact portions and interposed in a current conduction path, and a movable contact having a pair of movable contact portions capable of contacting to and separating from the pair of fixed contact portions. At least one of the pair of fixed contacts or the movable contact is formed in a shape to form magnetic fields generating Lorentz forces opposing electromagnetic repulsion forces generated in an opening direction between the fixed contact portions and the movable contact portions when current is conducted. External connection conductors are connected to external connection terminals of the fixed contacts, an attachment direction of fixed portions fixed to the external connection terminal of the fixed contacts is set to cross a current flow direction flowing through the movable contact.