where is in a relay silver?

[Hannibal Smith]

Hi,
i have ca. one hundret relays from busses.
Is there silver in it and where is it?

Regrads.
Max

 

[rusty]

Hi,
i have ca. one hundret relays from busses.
Is there silver in it and where is it?

Regrads.
Max

Relays from electric trolley transport should have a silver/palladium alloy in the contacts. Pictures would help to show you where the contacts are located.

Regards
Rusty

 

[macfixer01]

Inside most electromechanical relays the contacts are pretty easy to spot, as opposed to solid state relays. There will be some moveable arms that are attracted to an electromagnet with a coil. Somewhere near the end of those arms (opposite end from the pivot point) there will typically be attached flat pads or rounded beads of silver or gold-plated material. Often relays have contacts on both sides of the arms so they connect one set of contacts while at rest (the normally closed set) and a different set of contacts when energized (the normally open set). Here is a photo I found online:

http://tinyurl.com/3fzkhqm

So you can see there the center contact connects to the right one while at rest, or to the left one when the coil is energized.

macfixer01

 

[Hannibal Smith]

Thank you!
Thats good. All of them have silvercontacts.

Regrads.
Max

 

[macfixer01]

Thank you!
Thats good. All of them have silvercontacts.

Regrads.
Max

That's good. Power relays meant for switching line voltages or an inductive load usually have silver contacts. Lightweight signal switching relays tend to have gold contacts since a lower resistance is more important and there isn't enough current being switched to damage the contacts.

macfixer01