1st time visitor - Need simple 12v Timer for Generator Circuit...

Discussion in 'The Projects Forum' started by radicalfarm, Aug 29, 2007.

  1. radicalfarm

    Thread Starter New Member

    Aug 29, 2007
    6
    0
    Gday everybody. I was looking online for help & came across this forum so thought I would post...I have a love of electronics but not much knowledge so please bare with me!

    I need a simple timer-switch for a remote diesel generator. The generator will be switched on via a PL60 Plasmatronics regulator when our solar battery bank gets to a predetermined voltage.

    The circuit needs to be Normally Open - then when it switches there needs to be a positive current to a relay to keep the injector solenoid open (so far so good next bit is what I am having trouble with). There also needs to be a timed output to the starter relay of 1-2 seconds.
    That's it. Simple I know, but the timer bit is hard to find info on. Do I use a 555 circuit? (I don't really know how or what this is but read a bit about it in another forum - looks a bit complex for something so simple?

    Anyway if you have the time to reply it would be highly appreciated stuff@ploth.com

    Adam
     
  2. radicalfarm

    Thread Starter New Member

    Aug 29, 2007
    6
    0
    Sorry guys thought I would add some details that I have found I need to clarify as I read other searches etc.

    The input pulse coming from the regulator is constant (ie it will switch on & stay on until the generator is meant to turn off) & I have found that people talking about the 555 timer say that you can't use it as a Monostable timer if the input source is longer than the output> Is this true? I am still hoping to find something simpler than a 555 but anyway...

    If this is the case, which of the below is needed?
    What is my circuit a rising edge or a falling edge?

    Sorry for my ignorance!


    -------------------------------Copied from another site-----------------
    More about triggering

    For a simple 555 monostable, the trigger pulse must be shorter than the output pulse. Sometimes you want to trigger the monostable from a longer pulse:

    triggering from a falling edge

    The trigger network detects the falling edge at the end of each Vin pulse, producing a short 'spike' which triggers the monostable at the appropriate time. The period of the monostable pulse is shorter than the period of the Vin pulses.

    If you want to trigger the monostable from a rising edge, you need to add a transistor NOT gate to the trigger circuit:

    triggering from a rising edge
    ----------------------------------------------------------------------
     
  3. nanovate

    Distinguished Member

    May 7, 2007
    665
    1
    Yes this is true but you can use a circuit that will generate a short pulse.

    You can also just buy a "canned" relay-timer or use an RC timeout circuit.
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    One of the Plasmatronics brochures says
    The signal you are using doesn't seem to be sophisticated. Are you sure the functions you need are not already available?
     
  5. radicalfarm

    Thread Starter New Member

    Aug 29, 2007
    6
    0
    Gday guys - thanks for the reply!
    Nanovate - I will look into a canned circuit or RC time out? > where would I find one... and do you mean I should make a circuit that changes the continuous output trigger to a pulse, so that the 555 will work? Sounds like it is getting a bit complex for the likes of me!

    Ron - where would I look for something already available?

    I will try searching for RC timeouts & see...

    Adam
     
  6. radicalfarm

    Thread Starter New Member

    Aug 29, 2007
    6
    0
    Sorry Ron - I just realized you were quoting from the plasmatronics brochure. Yes I read that too - and was excited but it only seems to mean that it will start & stop the geny in a variety of different circumstances...it states that the 'generator start sequence must be handled by the generator' - what a let down! I have emailed plasmatronics with no response yet...
     
  7. radicalfarm

    Thread Starter New Member

    Aug 29, 2007
    6
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    Would this work ?

    Attached scematic from another site:


    Substitutions
    R1 1 1 Meg Pot
    R2 1 10 K 1/4 Watt Resistor
    C1 1 10uf 25V Electrolytic Capacitor
    C2 1 0.01uf Ceramic Disc Capacitor
    D1,D2 2 1N914 Diodes
    U1 1 555 Timer IC
    RELAY 1 9V Relay
    S1 1 1A 120V SPST Switch
    MISC 1 Board, Wire, Socket For U1
     
  8. nanovate

    Distinguished Member

    May 7, 2007
    665
    1
    Here is an example of a triggering circuit:http://www.doctronics.co.uk/555.htm#triggeringYou want the 555 timer to not retrigger. If your trigger pulse is short then you can just hook up the 555 as a monostable and set the RC for your desired delay.

    Look up time delay relays also. They are a bit pricey though.
     
  9. radicalfarm

    Thread Starter New Member

    Aug 29, 2007
    6
    0
    Thanks - in that diagram the OV is that the earth (neg)?
    ALso there is an X in a circle what is that?
    THe rest I'm sure I can figure through searching.

    Then just need to work out who sells the stuff in Australia through the net,..
     
  10. nanovate

    Distinguished Member

    May 7, 2007
    665
    1
    Yes

    That is a marker for the diagrams below the circuit. "voltage at X"

    For the time delay relays many electrical shops that sell supplies for electricians and industrial techs would carry them. Omron, Omega and Potter Brumfield make them (along with others). For the LM555 you can also get SA555, SE555, MC1455... wikipedia has a list of alternate part numbers.
     
  11. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    I meant, is the capability built into your controller?

     
  12. vikanuf

    New Member

    Mar 5, 2008
    1
    0
    Hi, You may find some interesting things by visiting http://www.gencontrol.co.uk
    These guys offer a low volt battery autostart for a generating sets.
    Regards,
    Vik
     
  13. knowitall

    New Member

    Jan 10, 2010
    17
    0
    Dear Adam;

    You failed to mention if your control unit ( pl 60 ) just closes contacts or supplies actual voltage, I"m assuming closed contacts, you can go nuts with all kinds of 555 gimics or, if the solonoide current draw is not to great use a large value capacitor to activate the remote diesel start mech.( What a break thru) , put various large value electrolytics in line with the 12v supply ( pl 60 ) and the load, your remote start mech. unless the starter is on line ( 400 ) amps then it should work just fine, with only one added part, the rather large electrolytic cap, it might go onto the thousands of Mfd. I would rekon ( ausie word ) about 10,000, Uf. ( Just a guess ) for a small gen. which I surmised your using, if you need furthur tech. details, please send 4,000 U.S. and provide the Foster's Lagar, and after extensive screening will be on my way, wondering why I would go into the out back with 59 known killer snakes to contend with and out of control aussies?

    Cheers Mate
    Jack from Ronan
     
  14. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    To knowitall - you might make a habit of checking dates. We have no way to designate if threads are active or not, but two years of inactivity usually means no further interest.
     
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