How many enterprises can switch silver contacts for professional applications?

A contact switch is a switch that uses metal contacts to open or close a circuit, turn off current, or make it flow to other circuits. In the field of silver contact, it is generally divided into pure silver contact, silver-nickel alloy contact, silver-tin oxide contact, silver-cadmium oxide contact.

But the general switch industry has a certain scale of production and application of enterprises know how to choose silver contact to ensure the switch and quality of life, and many small and medium-sized enterprises lack of understanding of the degree of silver contact, widely used in the switch industry silver cadmium oxide and nickel silver alloy contacts, but the proportion of the production process do you know?

Silver nickel 10 12 15? Or silver nickel 20? Is it silver cadmium oxide or silver cadmium? So many switch factories blindly compress costs or some small silver manufacturers use special technology to reduce costs to obtain profits.

In this small series as a switch, is our obligation switch industry simple popularization, take silver cadmium oxide contact, the ratio can be verified by a third party (metal composition analysis).

But in this process is difficult to control, perhaps some silver points do not oxidize this process, depending on how you choose the silver contact manufacturer.

The basic requirements of contactor relay is that the contact can be reliably connected to the circuit is closed, the contact conductivity is good, there is no rebound, the contact resistance is as small as possible, the load current can flow reliably, there is no tension and overheating arc; In the open circuit, the arc can be quickly extinguished, and the circuit can also be reliably disconnected, and the larger the resistance of the disconnect, the better.

The contact resistance consists of a shrink resistance and a film resistance. From the macro point of view, the contact surface of the relay contact is usually circular or flat, but from the micro point of view, only the local area has real contact, and the contact surface is actually uneven.

When the current passes through the local region, the current decreases, the current path increases, the effective conductive cross section decreases, and the resistance of the contracted region increases. This is the resistance to contraction.

There is a film layer with certain conductivity on the surface of these locally conductive micro-areas, and when the current flows through the contact point of the contact surface, the film resistance will be generated. The failure caused by the relay is not only the small number of contact melting jumps, but also most of the failure is poor contact.

The contact resistance of the relay increases with the adhesion of oxidation and chemical corrosion contaminants on the surface of the contact material. When the contact works at low voltage or small current, the contaminated contact surface will make the contact resistance unstable, poor contact or even open, seriously affecting the reliability of the relay.