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Wiring of a 12V 4PDT Relay

Discussion in 'Electronic Design' started by Sam, Jan 23, 2006.

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  1. Sam

    Sam Guest

    I am trying to follow the following schematic:
    http://www.scied.science.doe.gov/nmsb/pdfs/Buzzerset.pdf


    Radioshack no longer caries the listed 12V 4PDT relay. I was able to
    get a hold of a different 12V 4PDT relay, however I don't know if I can

    use it. I know nothing about the wiring of relays. The relay that I
    found has 14 pins instead of the 12 listed in the schematic. The pins
    are in 3 rows of 4 with the 13th and 14th pins on the 4th row and it
    looks like they connect directly to the coil. (I can email you a jpg
    of the schematic of the relay if this helps).


    Any help or direction would be appreciated.


    Thanks,
    Sam
     
  2. Ken Taylor

    Ken Taylor Guest

    Consider the pins to be in four rows of three - these are your four poles,
    and the sets of three will be a common (Com) pin, one which is
    normally-closed (NC) and one normally-open (NO).

    The pins 13 and 14 on your new relay are the coil and correspond to 4 and 12
    on the original one.
    The other pins on the original are:

    NC NO Com
    1 2 3
    5 6 7
    9 10 11

    When the relay is energized, the common contact switches over and connects
    to the normally-open. So you may be able to tell which are the common, NO
    and NC by looking (if it's a clear case) or by testing (multimeter and
    battery). Check resistance or continuity between pins to confirm which pin
    is which before and after energizing the coil. If the relay is marked with a
    polarity for the coil then connect up the battery in that direction
    otherwise either way is fine.

    If you still have doubts post the pinout and we'll give you a direct
    pin-for-pin chart.

    Cheers.

    Ken
     
  3. Guest

    Thanks for the quick response. I am still a little confused.

    The relay I have looks like this

    1 2 3 4

    5 6 7 8

    9 10 11 12

    13 14

    The case is clear and I can see that 1-9, 2-10, 3-11, 4-12 are normally
    closed. When power is applied across the coil (13&14), 1-5, 2-6, 3-7,
    4-8 become closed.

    A pin-for-pin chart would be great because I can't figure out how to
    match up what was written above to my relay.

    Thanks for your patience.

    Sam
     
  4. Guest

    Thanks for the quick response. I am still a little confused.

    The relay I have looks like this

    1 2 3 4

    5 6 7 8

    9 10 11 12

    13 14

    The case is clear and I can see that 1-9, 2-10, 3-11, 4-12 are normally
    closed. When power is applied across the coil (13&14), 1-5, 2-6, 3-7,
    4-8 become closed.

    A pin-for-pin chart would be great because I can't figure out how to
    match up what was written above to my relay.

    Thanks for your patience.

    Sam
     
  5. Ken Taylor

    Ken Taylor Guest

    Hi Sam. Good sleuthing. :)

    Old relay New relay
    1 9
    2 5
    3 1
    5 10
    6 6
    7 2
    9 11
    10 7
    11 3
    4 13
    12 14

    Someone better than me might figure it out but I don't see how that first
    relay can be 4PDT, but I admit to being half asleep still. Anyway, there's a
    suitable pin-for-pin table for you.

    Cheers.

    Ken
     
  6. Based on your instruction book...

    Try writing a "truth table" that goes like this:

    WHEN POWER IS NOT APPLIED TO COIL

    Blue wire is not connected to anything
    Red wire is connected to green wire
    etc

    WHEN POWER IS APPLIED TO COIL

    Blue Wire is connected to yellow wire
    Red wire is connected to black wire

    etc

    Then try looking at your relay and seeing how it should be wired to
    match the table.

    I have 30 of these 4pdt relays, they are very versatile and useful in
    all areas of life. I made some toy railroad control out of one,
    opening and closing a gate when train approaches.

    i


    --
     
  7. - 9
    1___/
    - 5

    I hope you can read the ascii art, does this help ?
     
  8. ehsjr

    ehsjr Guest

    Compare your new relay to the old relay to see
    if they are physically the same. My bet is that
    they are.

    If they are not, we'll need a schematic of
    the existing wiring to see what goes where.

    Normally on a 4PDT relay, the pins are grouped
    like this, in order left to right:
    NC (Normally Closed), NO (Normally Open), COM (Common)
    1,5,9
    2,6,10
    3,7,11
    4,8,12
    13 14
    The coil is pins 13 and 14. Or if you change the
    orientation:

    1 2 3 4 NC (Normally Closed) pins
    5 6 7 8 NO (Normally Open) pins

    9 10 11 12 COM (Common) pins

    13 14 Coil

    See the picture at the bottom of:
    http://dkc3.digikey.com/PDF/T061/1456.pdf

    Ed
     
  9. Guest

    Thank you all for your helpful answers. I was able to successfully
    follow the schematic and the buzzer system is working. Could not have
    done it without your help.

    Sam
     
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