asked on 3/25/2013

How to read ratings on a relay

I have to change out some relays and I noticed that what we have on hand are 24VDC (which is fine) relays but I noticed that it's rated at 10A 28VDC. Assuming I am reading this correctly and that's the maximum the relay will let through, how big of a problem is it if the unit calls for a 10A 24VDC relay? The difference is very slight, but over the 10% threshold.

Add to that there is one more 24VDC relay that is rated at 30A 28VDC, while the unit calls for 25A 24VDC. Again, how much of a problem is this?

Thank you.

Miscellaneous Hardware

Last Comment

thirtywinter

3/25/2013

Enabbar Ocap

3/25/2013

I'm guessing that is the switched current values and not the operating current and so having the contacts able to switch more than they need should just mean they are better able to cope. The contact sets should last longer and should be no trouble.

thirtywinter

3/25/2013

ASKER

Sounds good, but in the interest of due diligence, can you please take a look at these two pages as that are the two relays in question.

http://www.mouser.com/ProductDetail/Song-Chuan/731-DPDT-C-12VDC/?qs=Me3ZrpFQdnwxeNYjdkw%252bQw==

This is what I can find on the 30A. Part number for this one is 737-1Z-C1.

http://www.songchuan.eu/en/attachments/021_737.pdf

If you could take a look at those and sort of explain what you see I would appreciate that. Reason being that I am totally new to relays. :(
Like what does it mean when it says Contact Rating 10A at 28VDC. Does that mean what is maxed switched?

I really appreciate any help.

Thank you.

ASKER CERTIFIED SOLUTION

Enabbar Ocap

3/25/2013

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thirtywinter

3/25/2013

ASKER

Gotcha. Very informative. Thank you for clearing all that up.