review my design and let me know if anything will go wrong

Discussion in 'The Projects Forum' started by Andrew Rober, Mar 4, 2016.

  1. Andrew Rober

    Thread Starter New Member

    Feb 10, 2016
    this is a simple circuit yet as it uses 220 ac volts i'm think the smart thing is to ask experts if there is anything wrong with it before plugging it in

    i've a laser sensor with a relay that switches off if the beam isn't recieved
    a timer relay (delay on) which i use to turn the circuit on for certain amount of time
    a contactor which i use to first drive the load and second to latch the timer on for
    as long as the delay as cause the laser sensor only give me pulse

    please review my design and let me know if anything will go wrong

  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    Don't understand why you have labeled the supply as 1Khz and put a speaker across it, with the relay coils in series?
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    You ask what will go wrong but, after looking at your drawings, I cannot figure out anything and, therefore, cannot tell you what would go right or wrong. So, I think a clearer description of the problem (or your goal) with a step by step of how you think this will work.

    Also, a datasheet or link to this laser sensor relay would be helpful. And the time delay relay and what ever else you plan to use.
  4. Andrew Rober

    Thread Starter New Member

    Feb 10, 2016
    not 1k source, it's just 50/60 but i forgot to edit it

    laser sensor (rly2) switch on when interrupted which in turn switch on rly1 and rly3, rly3 is a timer (delay on) that will switch after 60 seconds, i use rly1 (contact) poles for latching the timer (after it receives the laser sensor pulse) and to drive the load which is 220v alarm

    you can find everything you need in those 3 pictures
  5. nerdegutta


    Dec 15, 2009
    I didn't find a datasheet in the link, nor did I find a clear description.

    To get better answers, you need to explain what you want to do, what you have available, links to datasheets/product pages, and what you think is wrong.

    It is very important that the files you upload are correct. If you forget to edit something, then you have to edit it and upload a correct version.

    Good luck. :)
  6. Andrew Rober

    Thread Starter New Member

    Feb 10, 2016
    i think there is nothing wrong with it, it's all that i want to be sure that it's going to work and it's as easy as a laser sensor turns on a timer with rly that turns on a contact, the contact latch the timer rly as it only receive a pulse from the laser sensor, it's as simple as that, everything works with 220-250v ac, that's really all there is to it
    here is everything useful on the datasheets
  7. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    I think you should stay away from 220VAC.
  8. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    Don't know where you are. In the USA, the other pole of 220 VAC is L2, not N. BTW, if it can go wrong it will. I suspect from your drawing that the latter applies.

  9. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    Having latched the timer relay on, how will you unlatch it?
  10. Magic Dr.Shoon

    New Member

    Nov 30, 2007
    It is hard to understand what you are trying to do when you use the wrong symbols and without describing the components better.

    As far as I can make out (from the CAD drawing, I can't read the scrawl at all!):
    • Relay 2 will energise when the laser beam breaks, closing its contact
    • Relay 3 will energise, wait for a period of time before opening the contact
    • I'm not sure about the link between the coils of relay 1 and relay 3. That link needs to be either L1 or L2 (+ or - as labelled on your drawing). For relay 3 to work it needs to be L1, for relay 1 to work it needs to be L2.
    • If relay 1 did manage to energise I can't see where the latch is. The coil on relay on relay 2 always has power anyway and only switches when the beam is broken. The bottom contact on relay 1 will power the siren, but top contact will link L1 with L1, and not achieve a great deal. There is nothing to latch relay 3 on; as soon as the beam is sensed again relay 2 will drop out again.
    What do you want to achieve?

    Do you just want to power the alarm in the event of the laser beam breaking? And do you want this alarm to be latched on, requiring a manual (or timed) reset to stop it?

    I'm not sure on what the purpose of the timer relay is.

    You can do simple latching relay circuits with just the one relay. Try Googleing "latching relay circuit" and clicking on the images tab.
  11. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    If you insert an appropriate fuse, then nothing will go wrong.
  12. Magic Dr.Shoon

    New Member

    Nov 30, 2007
    As long as it's put in the right place, and if this is mounted in a metal enclosure, the enclosure is earthed (including the base & the lid). I would also add on/off and reset functionality, and probably a whole load of other stuff.

    I would highly recommend that if you are going to go through with trying to build this circuit, that you prototype it and test it using an isolation transformer. That should limit the injuries when you give yourself an electric shock.

    Have a re-think, redraw your circuit (the CAD version is much more clear) and post it back in here, with links to all of the actual datasheets (rather than the snippets which you think are relevant).

    I'm happy to help, but this first attempt is quite a long way off working.