Electromagnetic Relay Iron Overlap for Contact Repulsion
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Solution Overview
Problem
High current supply in electromagnetic relays leads to electromagnetic repulsion, causing arc discharges and potential fusion of contacts, which existing designs fail to adequately prevent without increasing relay size.
Innovation Solution
The design incorporates fixed and movable irons arranged such that magnetic attraction opposes electromagnetic repulsion, using a configuration where the movable iron partially overlaps the fixed irons, allowing for effective contact management without increasing the relay's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If irons are provided to generate magnetic attraction opposite to electromagnetic repulsion, then contact opening due to electromagnetic repulsion is prevented, but the relay size increases due to additional space required for the irons
Solution Approach 1:
The patent positions the movable iron in the width direction between the fixed irons, utilizing the width dimension of the relay structure. This spatial arrangement allows the movable iron to overlap both fixed irons in the width direction, creating magnetic attraction paths in multiple dimensions without extending the overall relay envelope, thus preventing contact opening while maintaining compact size
Solution Approach 2:
The movable iron is nested within the space defined by the fixed irons in the width direction, with the movable iron positioned between and overlapping both fixed irons. This nested arrangement maximizes the use of available internal space, allowing the magnetic attraction mechanism to be integrated without increasing the external dimensions of the relay
2Power
If high current is supplied to closed contacts, then power transmission capability is improved, but electromagnetic repulsion increases causing contacts to open and arc discharge to occur
Solution Approach 1:
The patent introduces irons (fixed irons and movable iron) that generate magnetic attraction force in the direction opposite to the electromagnetic repulsion force between contacts. This counteracting magnetic attraction serves as a 'force counterweight' that balances the repulsive force, allowing high current to be transmitted without causing contact opening or arc discharge
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 reliably prevents contact opening due to electromagnetic repulsion, maintaining contact integrity and reducing the relay's size, while ensuring proper operation and resistance to shock and vibration.
Implementation Method 1
attraction due to a magnetic flux generated by an electric current flowing through the fixed terminal and the movable terminal is generated in a direction opposite the direction of electromagnetic repulsion between contacts
Implementation Method 2
electromagnetic repulsion between the contacts increases due to the high current
Data Source
AI summary
An electromagnetic relay includes a movable terminal including a movable contact, a fixed terminal including a fixed contact that faces the movable contact, first irons disposed on one of the fixed terminal and the movable terminal, and a second iron disposed on another one of the fixed terminal and the movable terminal such that the second iron at least partially overlaps both of the first irons.