Relays

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Relays are mechanical switches that are controlled by an electromagnet. It's a basic building block in a lot of equipment, for example in cars, telephone switches, power distribution and motor control.

As relays are used to switch signals and electrical currents they often uses precious metal in the contact to reduce electrical resistance and make a good connection. For small signal relays gold plated on silver, silver, silver palladium alloy or pure palladium is used, while at higher currents the metal of choice is silver or silver tungsten alloys.

Relays comes in a huge number of different varieties but from a refining point of view they could be sorted in two different categories. High power or small signal.

  • Small signal relays are used in telecom equipment, measurement systems and other systems not used for switching power. From these we get small contact points with silver, palladium and gold.
  • High power relays are used for switching power. They are found among other places in motor starters, lighting systems for large rooms and power distribution boxes. These relays are often called contactors and we get silver and silver tungsten alloys out of these.

References

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