Pulsing a DC power supply

Discussion in 'Off-Topic' started by Bhargavkr, Sep 15, 2010.

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  1. Bhargavkr

    Thread Starter New Member

    Jun 16, 2009
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    Thanks for the reply " beenthere" ... Iam not able to use the thread anymore as a closed button has replaced the reply button, so iam posting on a new thread . I hope the moderator can help me with this.

    All right , thats a start for improving the circuit . iam going to put in a isolation transformer on the " line in " and i have modified the original circuit.

    Further i found a circuit which looks fairly simple to build and the output is a square wave with pulse width and frequency control. Any comment on the circuit and if i can get 10-200hz output control with it.

    Further , my original questions
    1) Can use this pulsing circuit as the input for the DC SSr ??
    2)What exactly need to be the value of inductors for an electrolysis load of max designed load 15amps , 200V dc.

    Thanks for the help again,
    Bhargav

    Quote from original post ********************************
    Hello Group,
    I have a 200V 15 amps DC CVCC benchtop power supply. Iam trying to develop a electrolysis system and i require 10-200hz adjustable squarewave pulsed dc. { worst case 200 hz fixed :( }

    As this is for a electrical type of power supply , i do not need high precision on the square waves . This is the idea i have till now for the power supply .

    Line Ac --Isolation transformer -- DC rectifier -- DC Capacitor --DC SSR-- Inductor -- Load
    | |
    DC pulsing circuit

    As iam not a professional electrical engineer and i cant get any local company to take up development of the power supply for a single number requirment , iam stuck for over 1 year trying to get professional help. With frustration , iam trying to build my own and i really need help on putting exact numbers on the circuit components. Please help me ...

    1) What should be the output of the pulsing circuit to generate square waves on the output of SSR?? will something of this sort work " http://cgi.ebay.com/ebaymotors/Const...Q5fAccessories "

    1a) Is there any place where i can buy any standard square wave pulsing circuits on the net ?? any links will be veyr helpful

    2) How do i go about fixing a value on the inductor ? The load is an electrolysis system which behaves like a resistive load . Max designed operating parameters are 15 amps , 200 V dc.

    Any other precaution i need to take , like maybe a diode somewhere??

    If anybody wants to help even professionally , i would be very grateful , please message me at <snip> ( please replace dot with . )

    Regards,
    Bhargav

    end quote ****************************
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. Wendy

    Moderator

    Mar 24, 2008
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    To the OP, you have stumbled onto one of the hard core rules here, an isolation transformer must be used, or this thread will be closed again.
     
  4. Bhargavkr

    Thread Starter New Member

    Jun 16, 2009
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    Thanks moderators ... i have noted the change onto my circuit here :

    Line Ac --Isolation transformer -- DC rectifier -- DC Capacitor --DC SSR-- Inductor --Load
    ............................................................................................| |
    ................................................................................. DC pulsing circuit

    I hope i have put the isolation in the right place.

    I will procure one as soon as possible as iam currently running a ac/dc conversion circuit without it :)

    With the isolation in place , can anybody please help me ...

    Regards,
    Bhargav


     
    Last edited: Sep 15, 2010
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    One question remains to help understand what you are attempting. Electrolysis is a continuous process. It works only while a current runs through the liquid - http://en.wikipedia.org/wiki/Electrolysis

    What is the purpose of the pulsing? All it will do is cause less gas to be evolved per unit of time.
     
  6. Bhargavkr

    Thread Starter New Member

    Jun 16, 2009
    4
    0
    Hello "Beenthere ",

    Pulsing with low frequency (10-200hz ) helps keep the heat produced in the electrolysis process low.

    Pulse width modulation helps keep the max current consumed by the load in check. As i have no clue how to go about pulse width modulation , i have just put in AC capacitors in line with the AC mains so that it acts as a current limiter . Will post pics tomorrow .

    To indicate in the circuit :

    Line Ac --Isolation transformer --AC capacitor -- DC rectifier -- DC Capacitor --DC SSR-- Inductor --Load
    .................................................. ..............................................................| |

    .................................................. ................................................ DC pulsing circuit


    Please let me know if i can provide any more data...

    Thanks,
    Bhargav
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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    It is important to understand why you have chosed to use such amazingly high voltages when the reaction is produced by much lower voltage and may then be completely controlled by regulation of current. So far, this appears to be incredibly dangerous for no apparent purpose.

    Is there some actual valid reason for the use of such high voltage? What material are you electrolyzing? There is a vast body of knowledge that describes the process of electrolysis - why aren't you trying to use that information?
     
  8. t06afre

    AAC Fanatic!

    May 11, 2009
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    I this case I would say the use of an isolation transformer will hardly make any difference regarding safety.
     
  9. Bhargavkr

    Thread Starter New Member

    Jun 16, 2009
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    Hello again,
    The reason for using high voltage is that the load is an industrial grade hydrogen generator electrolysis system for cutting steel. The load necessiates the use for multiple electrolysis cells ( each consuming 2V ) to be lined up in series so as to produce high gas output .

    Now there are low voltage (12V , 75 amps ) systems widely available on the internet but the problem is iam not able to find a high voltage system readily available even after a lot of research ...

    SO , i got in touch with a electric circuit designer who just specified the circuit architecture to me but wouldnt work on the circuit as he was already busy . thats how i got so far ...

    Iam presently using a continuous DC and it is working well but i want to make a commercial system and i want to ensure the best output and professional system but cant find anybody interested to help me :(

    Well thats about the load . I made a video a year back about the load and electric circuit being used " http://www.youtube.com/watch?v=otB-cXlxFZk" Maybe this might help you see better what i am trying .

    I have come a long way form there and bettered the equipment . Now i want to create something commercial and useful to the society :)

    Regards,
    Bhargav
     
  10. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    Well, using old Bob as a starting point means the concept is not valid. Which is to say it is based on a scam.

    I you are interested, you may read through linked threads in the link here - http://forum.allaboutcircuits.com/showthread.php?t=28067

    All these electrolysis schemes are based on completely bogus theory, and will no longer be discussed in these forums.
     
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