what means starting voltage in solenoid valve?

Discussion in 'General Electronics Chat' started by mohammad2050, Nov 17, 2015.

  1. mohammad2050

    Thread Starter Member

    Nov 14, 2014
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    i want to drive a pneumatic ejector(solenoid valve), is specifications in following:

    Starting Voltage : 100V
    Maintaining voltage : 12V
    Resistance Value :18Ω
    Frequency(Hz):500-800
    Maximum instantaneous power : 200W
    Standby power : 3W​

    what means starting voltage ? i know that i need to build a magnetic field across a gap. Then the gap closes so i need much less power (12 volt) to hold it in place. And 0V to let it turn off again but 100 volt is where? and how build circuit for drive?

    do is below circuit appropriate ? if yes, 100 volt is where and how can obtain values?
    [​IMG]
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    The way I interpret the specs; no. The solenoid requires 100V (which seems high) to turn on and 12V to hold (it on). Lowering the voltage on the solenoid coil after it has engaged is to reduce power consumption.
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Do you have a data sheet or link to one?

    This solenoid is the type that needs to be pulsed (initially) with a high voltage, and then switched to a lower voltage to hold it in. If the high voltage is applied too long, the solenoid burns up due to excessive power dissipation...
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Specs say 500-800 hz, so it must be AC.
     
  5. mohammad2050

    Thread Starter Member

    Nov 14, 2014
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    no , i want to buy this solenoid and producer send me this specification

    ok, i think too , but how?
     
  6. mohammad2050

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    Nov 14, 2014
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    500-800 hz is number of open/close that can doing solenoid in second , i think that it is different with voltage level every pulse
     
  7. dl324

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    Mar 30, 2015
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    The obvious solution is to put a resistor paralleled with a capacitor in series with the solenoid coil. The RC time constant needs to be long enough for the solenoid to pull in.

    The problem will be discharging the capacitor if the solenoid is switched quickly or you want it to be able to respond to momentary power glitches.
     
  8. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Two ways:

    100Vdc power supply, NFET switch which is turned on for a few tens of msec.
    12Vdc supply, NFET switch which is turned on after the one above turns off.


    Other way: 100V supply and a switched constant-current driver. The voltage across the solenoid will drop to a steady-state value of I = E/R = 12/18 = 0.67A.
     
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    That only applies to a DC solenoid.

    Cannot the OEM supply a more in depth spec sheet as to exactly what is needed?
    Max.
     
  10. mohammad2050

    Thread Starter Member

    Nov 14, 2014
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    ok , in your opinion do this circuit can doing 500-800 switchs in second?
     
  11. mohammad2050

    Thread Starter Member

    Nov 14, 2014
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    it is china product
    i ask of them but they send me only this spec.
     
  12. MikeML

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    What is the inductance of the coil? Is this some sort of proportional valve?

    To actively drive it both open and closed at that rate will be very difficult. It will require split + and - 100V power supplies, and very powerful, very expensive, high voltage, high power opamp, like these: See PB63.
     
  13. marcf

    Member

    Dec 29, 2014
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    100V^2/18ohms = 555Watts
     
  14. mohammad2050

    Thread Starter Member

    Nov 14, 2014
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    i dont know
    yes
    thanks for this help
     
  15. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If it is pneumatic it is very unusual to be a proportional type, these are usually hydraulic for accuracy.
    Can you post a pic of the solenoid?
    Max.
     
  16. MikeML

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    Oct 2, 2009
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    No! the inductance of the coil limits the power dissipation during the initial period when the 100V supply is first applied. You apply 100V, the current builds up. When the coil current reaches its steady-state limit (12V/18Ω = 0.67A), you switch from an applied 100V to 12V.
     
  17. mohammad2050

    Thread Starter Member

    Nov 14, 2014
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    [​IMG]
     
  18. MikeML

    AAC Fanatic!

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    @mohammad2050 ,

    Are you planning to use pwm? if so, what pulse frequency?

    This will likely need a bipolar, constant-current driver with split +-100V supplies. In other words, you need to actively drive the coil with both current polarities.

    You could use a single 100V supply, and an constant-current H-Bridge to reverse the current in the coil.
     
  19. mohammad2050

    Thread Starter Member

    Nov 14, 2014
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  20. MaxHeadRoom

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    If proportional, where is the feedback device, do all apertures activate at one time?
    It appears to be just an on/off control?
    It is still not clear on the mechanics of the device.
    Max.
     
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