Quiet operating latching relay

Discussion in 'Electronics Resources' started by keithscarfe, Nov 7, 2012.

  1. keithscarfe

    Thread Starter New Member

    Nov 6, 2012
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    Hi.
    Does anyone know if it is possible to get a quiet (silent preferably) latching relay?

    I have a regular (danfos) digital thermostat to control the house heating but the switching relay in side is so loud when it clicks over and since the unit is mounted in my bedroom it wakes us up.

    The relay is an omron G6CU-2114P-US.
    Data sheet is here: http://www.omron.com/ecb/products/pdf/en-g6c.pdf

    I was wondering if anyone knew of something I can just replace it with. I was thinking a solid state relay but I guess this wont work as the point of the latching relay is not to draw power when not operating. Since the thermostat is battery powered it would need to be another latching relay. I dont want to go modifying the circuitry, just replace the relay.
    Anyone any ideas what I can do. I have thought of relocating the unit but this would defeat the point of it being located where it is, or get a wireless type one, but I just wondered if there might be a direct replacement for this relay that is quiet in operation.
    Thank you for any pointers.
    Keith.
     
  2. crutschow

    Expert

    Mar 14, 2008
    12,988
    3,226
    If you need isolation of the control signal from the output, then it is problematic that a solid-state solution can be found that takes no current when latched.

    I'm curious as to why such a large relay (8-10A) is needed for the thermostat. Normally a thermostat switches much less than an amp. If you are indeed switching a small current then you might consider a much smaller latching relay. The sound of the contacts moving is somewhat proportional to the size of the contacts and mechanism. Also wrapping the relay in foam might help some.
     
  3. keithscarfe

    Thread Starter New Member

    Nov 6, 2012
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    0
    Ok yes thanks. I'll try to find a smaller one. Do you have any references at all? i.e. where I should look (I am in the UK). I'll attach it raised up off the board as much as I can and wrap it as you suggest - good idea.
    Thanks.
     
  4. crutschow

    Expert

    Mar 14, 2008
    12,988
    3,226
    Just look for a single-coil latching relay with the same coil voltage rating and with a contact rating of perhaps 1A. The present relay has an usual contact configuration of 1 SPST-NO and 1 SPST-NC. If you can't find that just get a DPDT relay.
     
  5. keithscarfe

    Thread Starter New Member

    Nov 6, 2012
    4
    0
    Thanks for the help.
    I have ordered a IM43TS, data sheet here:
    http://www.farnell.com/datasheets/477186.pdf
    I think this will do the job. Will be interesting to see how much quieter it will be. I'll report back when fitted.
     
  6. keithscarfe

    Thread Starter New Member

    Nov 6, 2012
    4
    0
    Fitted ok. The new one is much smaller than the original so I had to mount on some stand off legs that I made from resistor legs. Is working fine and is very quiet indeed compared to the big one. Not silent but a huge improvement. I just hope it lasts and will be able to drive the load ok in the future. So far seems ok.
    Cheers.
     
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