solenoid with a 555?

Discussion in 'The Projects Forum' started by ale2121, Apr 16, 2009.

  1. ale2121

    Thread Starter Active Member

    Mar 20, 2009
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    so i have a bunch of solenoids. i tried hooking them up to power and flicking the switch on and off. i noticed that when i flicked the power switch off, the solenoid held it's position for a while before it released. I assumed this was useless for my purposes. BUT, then I recently started thinking it might make a difference when different frequencies are applied to the solenoid? does anyone know about this?
     
  2. DrNick

    Active Member

    Dec 13, 2006
    110
    2
    The flux in the circuit that is acctuating the contact does not just go away immidiatly. As the flux discharges, a reminant magnetic force keeps the contact pulled in for a moment after the control signal has been removed. That said...how big are these solinoids...it will take a pretty big coil to have a noticable delay or some weird mechanical property that could keep it pulled in.
     
  3. ale2121

    Thread Starter Active Member

    Mar 20, 2009
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    it's this solenoid:
    http://www.sciplus.com/singleItem.cfm/terms/15383

    i've got a 12v bench supply powering it. i added a spring and a pin at the top to try making it bounce back faster, but it won't.

    so the frequency doesn't make a difference?
     
  4. italo

    New Member

    Nov 20, 2005
    205
    1
    relays are not switching components are slow as molasses and nasty gives spikes ionize the air if close enough it is after all a mechanical electrical device.
     
  5. ale2121

    Thread Starter Active Member

    Mar 20, 2009
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  6. DrNick

    Active Member

    Dec 13, 2006
    110
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    It looks like those are being driven by servos with pneumatic actuators, hence the description in the video...

    "Pneumatic drums and guitar at the Maker Faire"
     
  7. ale2121

    Thread Starter Active Member

    Mar 20, 2009
    71
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    yeah, i got that.

    how does a servo with a pneumatic actuator work?
     
  8. DrNick

    Active Member

    Dec 13, 2006
    110
    2
    A servo is really just a small motor. That motor drives a pump. The working fluid in the pump then drives whatever motion you want. Google it I am sure there are lots of good resources on hydraulic systems online.
     
  9. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,170
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    Lots of interest in solenoids lately in AAC, lholze, Proj., kiel long Chat, jdm2008, Proj.,And123, Proj. One question, was your switch on powersupply or between pwr. & solenoid? SgtWookie not too long ago gave some references for snubbers which you would find usefull in speeding up solenoid turn-off.
     
  10. ale2121

    Thread Starter Active Member

    Mar 20, 2009
    71
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    it was the power supply switch, not something in between.

    what is a snubber? i looked at schematics online, but most were meant to lengthen the life of relays.

    are those all users with solenoid info?
     
    Last edited: Apr 18, 2009
  11. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    After switching off power supply , there is a lot of charged capacitors to supply current to a load. When current to an inductor is interupted, the collapsing field generates a high voltage, 100's to 1000's. Placing a diode across the inductor, supplies a load to disipate the charge, which also slows down the release, in the case of a relay or solenoid. A snubber is a balancing act between speed and V spike. Adding some resistance in series with diode improves speed but does not completely eliminate V spike. Then use higher V switch[MOSFET].
     
  12. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,170
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    All had something to do with solenoids, I think. Another post yesterday, seesoe ,Proj. ' Sense & triggrr later", gives reff. to a video on pneumatic control.
     
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