Relay- Maximum switching voltage

Discussion in 'General Electronics Chat' started by nileshkhupase, Oct 20, 2011.

  1. nileshkhupase

    Thread Starter Member

    Mar 22, 2011

    i have a relay RT425024, in its datasheet they have mentioned one parameter as "Max. switching voltage" as 400VAC.

    what is this parameter for? what does it signifies?
  2. colinb

    Active Member

    Jun 15, 2011
    That is the maximum voltage that the relay contacts are specified to handle. Any higher and there might be insulation breakdown failure and/or arcing or other Bad Things.

    The coil rating is different and is often something like 12 V dc (or ac) with minimum and maximum current given.
  3. Mike33

    AAC Fanatic!

    Feb 4, 2005

    I also have a relay question that fits well with this topic:
    1) what is a 'typical tolerance' in terms of the max voltage? (would 13V be too much? Unfortunately I don't have a datasheet...RS parts! Easy to find the dropout voltage, not so easy to safely learn the max!!!!).

    2) If you are using a 'cheaply rectified' ac source to trigger your coil, and you have a LOT of ripple (like, 20%!), should you think in terms of the RMS voltage or peak voltage when sending it to the coil?? I have to know ahead of time when setting up a voltage divider for 5 units what the correct way to go is. And of course, I don't have the transformer to test the concept with! (16AC for a train, at my father in law's house). I could, of course, clean up the rippling DC signal, but then I have to get a bunch of caps, etc etc, and if possible would like to keep it simple....opinions?
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    1)Typically stated on the datasheet.. Some allow up to 150% of the nominal.

    2)Slight AC on a DC relay isn't gonna hurt it..If it buzzes clean it up..Geek out with this
  5. Mike33

    AAC Fanatic!

    Feb 4, 2005
    Thanks, Mac! :)