Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: PWM wave form

  1. #1
    Join Date
    Jan 2010
    Posts
    3

    PWM wave form

    Yea another newbie here. been reading alot for the past few trying to figure a course to take and build a system for one of my rigs. my question is this. What is the desired wave form that I want to get from a PWM I understand why to use one but I can't seem to find out what the wave should look like, or better still the range both in amplitude and frequency. Any ideas? Many micro controllers have a PWM function and would be a great candidate for a cell management system. First need to know what I need. Replies much appreaciated. Thanks!

  2. #2
    Join Date
    Jun 2009
    Location
    Fort Worth, TX
    Posts
    510
    The ideal waveform delivered to an HHO cell, is a constant, uniform, DC voltage. Most PWMs on the market are just simple ON/OFF devices that hit the cell with square waves. These square waves are horribly inefficient, due to high RMS currents, for realtively low AVERAGE current. You sound like you may know a little about electricity... High RMS currents have a higher power dissipation and will produce more heat. For example, lets say your PWM will output a 50% duty cycle square wave to your cell, and your analog meter reads 30A going into it. This 30A is the average current. However, to accomplish 30A at 50% duty cycle, your PWM would have 60A flowing for half the time, and 0A flowing the other half of the cycle. The RMS current of this(Root Mean Square), would be a whopping 42A. This means that your cell would produce the same heat as a cell with a smooth 42A going through it. However, in our example, you are only producing the amount of gas as a 30A DC cell... In other words, you would be getting the same gas output based on the average current. However, your heat buildup would be nearly 50% MORE.

    So, to answer your question, it's best to have a smooth DC voltage/current to your cell. This can be accomplished, but it requires a little more sophisticated electronics to handle this. I'm working on a device that isn't a PWM, but a complete control system. It outputs a fully adjustable voltage/current that is nearly DC, although has a slight bit of ripple to it. In other words, it puts out a near ideal waveform, increasing efficiency by doing so.

  3. #3
    Join Date
    Jan 2010
    Posts
    3

    Pwm

    Thanks, so from what you're saying the best thing for me to do is to use multiple cells and a KOH mixture to both control heat and output. It seems that this will simplify things a bit. Also the time spent driving each day is for the most part the same, about 45 minutes and this should make it easier to manage heat buildup.

  4. #4
    Join Date
    Jan 2010
    Posts
    3

    Pwm

    Wait a minute, I missed your point on this. Ideally what I want to do is to build a constant current power source that will vary the output voltage inorder to keep output current steady regardless of the resistance of the electrolyte right? So why PWM? It seems that I've read something about the benefit of using PWM is to help breakup the water into a monoatomic state (Browns gas) resulting in larger quantities of more efficient HOH. is this true?

    Thanks,
    Steven

  5. #5
    Join Date
    Jun 2009
    Location
    Fort Worth, TX
    Posts
    510
    That "rumnor" is pure BS. Some people talk about a PWM causing the water molecules to resonate, thereby breaking them up. No. All a PWM does, is throttle the average power delivered to the HHO cell. I'm not sure what you've heard, but this whole notion of "Brown's Gas" being soe kind of magic gas unknown to modern science, is again, BS. Some call it Brown's Gas, some call it HHO, and still other(most of the world) call it a stochiometric ratio of H2 and O2. We are putting the water under electrolysis.

    If you take a detailed look at where these myths are coming from, it's usually someone trying to sell their "revolutionary" product on ebay, or some other site. The bottom line is, you should strive to produce the most amount of HHO, with the least amount of power. In other words, get the highest efficiency. Plate spacing, electrolyte concentration, plate resistance, and PWM efficiency are the main areas of concern in doing so.

  6. #6
    Join Date
    Jul 2009
    Location
    Australia
    Posts
    23

    Pwm

    My HOD has 14 plates 80 sq inches each. It won't operate at less than 100 amps and works best at 200 amps. At 30 volts. The HOD holds 22 liters of water, 6 KG KOH ans 1.5 KG of NaOH. Makes about 10 LPM. I power it with a electric welder and a rectifier. After 40 hours of test running the electrolyte is now clear. My question is is it the size of the plates that make it require so much power. It is designed for commercial use. I have had two PWMs made, they have both gone up in smoke. To make 20 amps it absorbs 750 watt, or 1 HP, 10 HP is no problem in my application. Provided I can save 40% on fuel. I find the welders control system perfect and am about to build a DC welder into my test Ute. Any answers or comments, advice.
    Llew

  7. #7
    Join Date
    Nov 2009
    Posts
    103
    Quote Originally Posted by Philldpapill View Post
    That "rumnor" is pure BS. Some people talk about a PWM causing the water molecules to resonate, thereby breaking them up. No. All a PWM does, is throttle the average power delivered to the HHO cell. I'm not sure what you've heard, but this whole notion of "Brown's Gas" being soe kind of magic gas unknown to modern science, is again, BS. Some call it Brown's Gas, some call it HHO, and still other(most of the world) call it a stochiometric ratio of H2 and O2. We are putting the water under electrolysis.

    If you take a detailed look at where these myths are coming from, it's usually someone trying to sell their "revolutionary" product on ebay, or some other site. The bottom line is, you should strive to produce the most amount of HHO, with the least amount of power. In other words, get the highest efficiency. Plate spacing, electrolyte concentration, plate resistance, and PWM efficiency are the main areas of concern in doing so.
    I wouldn't poo poo this "rumor", just the PWM that are sold as if they do this. I'm not saying that i know this one way or another, but I would expect that with a highly tunable PWM and a cell made to a .0001" tolerances you might find a frequency which is more efficient, it might be many ghz, and such a PWM may have inefficiencies that were greater than using a more standard frequency one. This is a subject that needs some experimenting with, but we're not there yet, and ebayers are behind us for the most part.
    I=V/R so R=V/I and V=I*R
    P=V*I
    (I=Amps, V=volts, P= power in watts, R=resistance in ohms)

  8. #8
    Join Date
    Jun 2009
    Location
    Fort Worth, TX
    Posts
    510
    You're right, Owen. I should say it's PURE BS, but the frequencies and setups that are typically used(<1MHz, DC square wave), they ARE BS. Your microwave oven is tuned to a fairly precise frequency(GHz range). This frequency is where water appears the most opaque(or more specifically, the permitivity is very high), causing the water molecules to indeed resonate, creating heat but no HHO.

    I'm currently working on a PWM that can handle 100A, and produce a true alternating DC waveform. The output will alternate betwen positive and negative polarities, applying +12V and -12V. The frequency will be fully adjustable up to about 1MHz, with a digital interface to a laptop or PC. This interface will give full control over many different features. Not your typical PWM, but more like a test and measurement controller. Fully updateable with new software when I fix or add something. It's gonna be cooler than ice.

  9. #9
    Join Date
    Jan 2010
    Location
    My home is in my head
    Posts
    2
    Hey phil', I think you are on the right track with the controller on an interface. I'm working on a controller that utilizes an acurately and widely adjustable pwm and stoiciometric ratio management with lenox and toyota to get the optimum system management. As for the stuff being for sale, I plan to make it universally available and adaptable. The cost to complete something like this is much more than I could afford, which is why I have recruited some help from the powers that be. The last two days have made me more optimistic about hho technology than I have been in the last 3 years.
    Although I don't subscribe to brown's gas due to the descreppnecies with the basic law of thermodynamics, I do however agree that equilibrium and precice resonance of electrolytic fragmentation is the key to unlocking the true potential of hho. Just like the wine glass that can be broken by the right pitch at a high enough decibal, water also has a specific ressonant frequency.
    This management requires similar components to your air -fuel ratio systems, but also ulliminates other stoichiometric elements.

  10. #10
    Join Date
    Aug 2008
    Location
    GA
    Posts
    1,079
    Quote Originally Posted by mistergoble View Post
    Although I don't subscribe to brown's gas due to the descreppnecies with the basic law of thermodynamics, I do however agree that equilibrium and precice resonance of electrolytic fragmentation is the key to unlocking the true potential of hho. Just like the wine glass that can be broken by the right pitch at a high enough decibal, water also has a specific ressonant frequency.
    This management requires similar components to your air -fuel ratio systems, but also ulliminates other stoichiometric elements.
    You dont subscribe to browns gas as far as what?
    When you're one step ahead of the crowd you're a genius.
    When you're two steps ahead, you're a crackpot."

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •