EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: MatCat on April 07, 2018, 02:55:09 am
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Greetings,
I am looking at relay KEMET EE2-4.5TNU https://www.digikey.com/product-detail/en/kemet/EE2-4.5TNU/399-11050-5-ND/4291116 (https://www.digikey.com/product-detail/en/kemet/EE2-4.5TNU/399-11050-5-ND/4291116) It is a double coil dpdt, my problem is I can't make heads or tails of how the pinout works...
Which 2 pins are the common poles? (I am guessing 4 and 9?) If that is the case then the default reset position is that 9 will be connected to 10 and 4 to 3? And set position would be 9 to 8 and 4 to 5?
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Secondary question, are the ratings per pole or in total? I.E. 125VAC at 0.5A, does that mean 0.5A per pole, or 0.25A per pole?
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Reset position 4=>3, 9=>10, set position 4=>5, 9=>8.
The ratings are for the contacts, so for each contact (when made, obviously).
Ratings are: carry 60W or 125VA, maximum switching voltage 220Vdc, 250Vac, maximum switching current 2A, maximum carrying current 2A. You have to derate so that the contact (current, voltage, power) all stay below their respective maxima. e.g. You can switch and carry 2A, but the 60W limit means that doing that you'd be limited to 30V, change to 1 amp and you can switch 60V, go all the way to 220V and you're limited to 270mA.
For long life it is a good idea to be very conservative about derating, especially make/break DC current. I'd also treat that reactive power specification (125VA) with caution and err on the safe side. Personally I wouldn't want 120W running through that tiny relay (two will fit on my thumbnail) even if the specs say that you can in theory. These were designed as signal relays and it'd be safest to treat them as such.
There is a huge 52 page manual for this range of relays under the title " MINIATURE SIGNAL RELAYS EC2 SERIES (DIP TYPE) EE2 SERIES (SMD TYPE) TECHNICAL DATA" that will tell you more about them than you imagined you could learn.
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I agree 120W would be a bit insane :D MAX VAC I plan to run in one of these is 10 watts, I am thinking it will be fine for that :). I do have the need for another relay that can handle 100W but I planned on finding a better suited one for that separately.