Contactor Iron Core Cathodic Protection Without Air Gap Increase
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Solution Overview
Problem
Existing contactors experience corrosion of the iron core in salt fog environments, leading to increased air gaps between movable and stationary cores, which reduces retention force without anti-rust coatings that further exacerbate the issue.
Innovation Solution
An iron core design incorporating a metal rod made of aluminum, aluminum alloy, magnesium, magnesium alloy, zinc, or zinc alloy that penetrates silicon steel sheets, forming a sacrificial anode to protect the core from corrosion and maintain retention force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an anti-rust layer is plated on the surface of the iron core, then the corrosion resistance is improved, but the air gap between the movable iron core and the stationary iron core increases, leading to a decrease in retention force
Solution Approach 1:
The patent applies cathodic protection by using a metal rod made of aluminum, magnesium, or zinc that is more electrochemically active than iron. This sacrificial anode corrodes preferentially, protecting the iron core from corrosion without adding any coating layer that would increase the air gap and reduce retention force.
Solution Approach 2:
The metal rod acts as an intermediary protective element between the corrosive environment and the iron core. Instead of coating the iron core directly, the sacrificial metal rod provides electrochemical protection, eliminating the need for anti-rust coatings that would otherwise increase the air gap.
2Ease of manufacture
If the surface of the iron core is coated with oil, then the cost is reduced, but the air gap between the movable iron core and the stationary iron core is still increased, leading to a decrease in retention force
Solution Approach 1:
The patent uses cathodic protection with a sacrificial metal rod to protect the iron core without requiring any surface coating. This eliminates the air gap issue associated with oil coatings while maintaining cost-effectiveness, as the metal rod provides long-term corrosion protection without the need for additional coating materials or processes.
3Force
If the air gap between the movable iron core and the stationary iron core is reduced, then the retention force is improved, but the corrosion protection of the iron core is compromised in salt fog environment
Solution Approach 1:
The patent employs cathodic protection using a sacrificial metal rod made of aluminum, magnesium, or zinc. This allows the iron core to remain uncovered (maintaining minimal air gap for high retention force) while the more electrochemically active metal rod corrodes preferentially, providing corrosion protection in salt fog environments without requiring any coating that would increase the air gap.
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 metal rod provides cathodic protection, reducing corrosion while maintaining the retention force by reacting with chloride ions, eliminating the need for additional coatings.
Implementation Method 1
the metal rod provides cathodic protection, reducing corrosion while maintaining the retention force by reacting with chloride ions
Data Source
Figure 1
AI summary
An iron core for a contactor and a contactor. The iron core includes an iron core body, the iron core body includes a plurality of silicon steel sheets fixed together by lamination, the iron core body further includes a metal rod, the metal rod penetrates and is fixed to at least some of the plurality of silicon steel sheets, and a material of the metal rod is one or more selected from the group consisting of aluminum, aluminum alloy, magnesium, magnesium alloy, zinc and zinc alloy.