Problem with SPDT Relay.

Discussion in 'The Projects Forum' started by fiatuno, Apr 8, 2012.

  1. fiatuno

    Thread Starter Member

    Jan 28, 2011
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    0
    Hi dear members, I have bought an OW5691 which is a 6V dc relay as shown in the below link:

    http://html.alldatasheet.com/html-pdf/105895/ETC/OW5691/53/1/OW5691.html

    System:
    http://www.reuk.co.uk/Simple-Sump-Pump-Controller.htm

    The main problem is that the datasheet is in french and this is a big problem for me. I have been having problems as I am building the below system which is a simple sump pump controller, which is controlled by two float switches giving 5V dc. Now I have managed to simulate this on proteus and it worked perfectly, but when in practice as always something is wrong. I built the circuit more than once and the relay doesn't seem to latch. It is supposed to latch when both switches are closed, until the last switch in the bottom of the tank is opened and it unlatches and stops the pump. Can someone give me ideas on why this relay doesn't seem to latch when the top switch is opened? Thanks in advance,
    Regards,
    FiatUno
     
  2. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    [​IMG]

    I've circled the portion of the circuit which facilitates the latching action. Check your connections of this segment. I'll bet that you don't have that connected. Verify with ohmmeter.
     
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  3. jimkeith

    Active Member

    Oct 26, 2011
    539
    99
    Another potential problem is the use of biased magnet relays in which the coil is polarity sensitive--if the relay will not pick up, try reversing the coil terminals.

    Biased magnet relays are more sensitive than the usual type--have higher coil resistance.
     
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  4. fiatuno

    Thread Starter Member

    Jan 28, 2011
    47
    0
    I think that is my problem, as I have double checked were you told and even all the circuit, and everything seems to be right, I think I need to buy unbiased magnet relays than.
     
  5. fiatuno

    Thread Starter Member

    Jan 28, 2011
    47
    0
    Would anyone give me a relay name which could do for me please as I have tried another one at school and it did the same thing. Thanks in advance, would greatly appreciate any help please.
    Regards,
    FiatUno
     
  6. jimkeith

    Active Member

    Oct 26, 2011
    539
    99
    Just play with the relay on the bench to determine if it picks up with either coil polarity--this will tell you immediately if it is a biased magnet type--I looked at the spec sheet & connection diagram and could find no evidence of coil polarity (normally marked with "+") --only indications on the coil terminals are 1 and 1'.

    My gut feel now is that it is not the relay.

    Experiment with your float switches to see if they are indeed functioning--this is not that difficult an exercise and you should be able to troubleshoot--when you go back over it again, make no assumptions as this is what leads to dead ends like this--another item to check is the pin-out of the form C relay contacts as this is easy to get wrong--as well as the pin-out of form C float switch contacts...
     
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  7. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    me too. OP seems to be getting the relay to switch, just not latch.
     
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  8. fiatuno

    Thread Starter Member

    Jan 28, 2011
    47
    0
    Thanks for all of your help, the problem was the relay that was not latching, I can't seem to understand why, but I managed to get my hands on another relay and with the same pinouts and circuitry, and worked out perfectly, thanks for all you help people.
    Regards,
    FiatUno
     
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