Contact of IVY Brand Electromagnetic Relay
Contact of IVY Brand Electromagnetic Relay
Before we understand the contact material of a relay, let's first explain what a contact is.How important is it as a part of the relay?Only by understanding these can we have a deeper understanding of the importance of contact material.The contact of the relay is in the state of normally open or normally close, which is simply understood as the contact of the relay that makes the circuit connect or disconnect.
Contact is one of the most important components of electrical relay. The performance of contact is affected by such factors as contact material, contact pressure, type of load, operating frequency, atmospheric environment, contact configuration and run-out. If any of these factors fail to meet the predetermined value, point contact problems such as electrochemical corrosion of metals between contacts, contact fusion welding, wear, rapid increase in contact resistance, etc., may occur. Among them, the contact material is the first factor to determine the contact performance.
Relay contact materials commonly used materials are :AgNi+ gold plating,AgPd, AgNi, AgCdO, AgSn02, AgSnO2 (including other oxide）, of course, there are other alloy materials, all related to the application (capacity withstand voltage).
Let's take a look at the properties of each material. AgNi+ gold plating: The coating has good corrosion resistance in the air. Compared with other materials, it has lower contact resistance and better consistency under small loads, and good conductivity and heat conductivity. AgPd: Good corrosion resistance, good vulcanization resistance, small contact resistance, good consistency and high price at room temperature. AgNi: It is the standard material for most dimensional electrical contacts, with good conductivity and heat conductivity, high ablative resistance, moderate weldability, and easy to generate sulfurized film in sulfide environment. AgCdO: high AC load, good conductivity, thermal conductivity, high ablative resistance, good adhesion resistance, easy to generate sulfurized film in sulfide environment.The contact material of IVY relay is AgSnO2, which can be said to be a combination of the above characteristics and has a long service life.
Electromagnetic relay utilize “on and off” of contact to realize the control of circuit. The contact voltage drop is different due to the difference of contact resistance between contacts. The greater the contact resistance, the greater the voltage drop at the contact. 1) Increase the contact heat and shorten the service life of the contact; 2) Reduce the effective voltage on the load.
In order to avoid the above effects, the contact resistance of the contact should be reduced as much as possible and the conductive material should be selected. Common materials are: red copper, silver, silver conductivity is better than red copper. For small relays used in small signal circuits, because the control current is small, contact surface is small, can also use gold-plated copper contact surface.
This is the introduction to the popular science of contact, expect to learn more about latching and power relay or seek more technical support, welcome to www.ivy-metering.com. It's really easy to reduce the rate of machine or device repairing.
