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Kerrowman

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  1. Hi Harry, The good point you raise about voltage headroom is presumably why 18V is supplied by the transformer in the full power supply circuit shown on that first link. However, the note nearby says that it has not been built so is it a bit of a gamble that it will work as indicated? The FET approach to dropping volts will work for the time periods I’m using for certain tests but for long term running I will likely need something more efficient. For the FET approach, in Spice simulation the FDS6699S mosfet works we
  2. Hi Harry, As suggested above I have drawn my own version of the power supply on the first link you gave using 5 LM338s. I could try and simulate this in LTSpice but that will take me a while. Any thoughts on whether it would do the job - probably better than the Buck converter? Jules
  3. Hi Harry, I have used this buck converter before but its never supplied even 20A consistently. In the first link you gave it talks about using the LM338 in parallel, as in the attached. Can I not stack 3 of them in parallel to do the job? If so I will assemble a circuit and run it by you? Thanks
  4. Thanks but my particular need is to take 12V, 25A max and make adjustable from 6-12V and a max current of 25A so would the attached from the previous link be suitable? I find the text doesn't make easy reading and is hard to understand. J
  5. Hi Harry, Thanks for the suggestions. The voltage regulator seems a good idea but I don't need the whole power supply but just an add on set up to adjust down the 12V nominal output I already have. Would I need then item 4 in the list? If so how is the voltage energy dissipated and how efficient is it overall? The motor controller uses a PWM approach it seems (12kHz) and I already have a PWM in my setup. Jules
  6. Hi all, I have a PWM power supply that has a nominal output voltage of 12V and a current capacity of 25A continuous. While there is about 0.5V adjustment on the PSU itself, I need to be able to adjust this output to supply 7-12V so I need to drop a few volts after the output. I will lose 1-2V due to a current flow of 10A or more but still need some further adjustment. I attach my suggestion based on an approach I used with a lower powered supply that used an MJE3055 and so am asking: 1. Would this arrangement work with the high power MOSFET (acting as a sort of valve like on a hos
  7. I've just run a Spice simulation and it seems, surprisingly, that the resonant frequency between points A & D is unaffected by having L3, the secondary of a transformer, in place. I had set the inductance of that coil at 3mH and being in parallel I thought it would have some effect but apparently not. While it's true that L3 would not be driven directly by the voltage source, but via induction from a primary winding, I doubt that would change this situation. Jules
  8. I'm assuming that resonance will still occur but, due to the extra inductance of the transformer secondary, it will be at a lower frequency (see attached). I will mock it up in LTSpice and see what happens. If that's ok then I will put some components together in the new year. The purpose of resonance is not to determine fluid level, which can be done with a simple float detector, but rather to make the most of the energy input in building up a high voltage across the electrodes. This method of electrolysis relies of the breakdown of the water dielectric while at the same time limiti
  9. Thanks for the suggestion. I have had another from an outside source which suggests that, if there was a transformer in the chain, then I could wrap some turns around the secondary as a detection coil and feed this coil to the comparator. At resonance this would detect a pulse? I have draw this up in the attached which shows some of the already built components. Do you think that might work?
  10. Hi there, I would like some help with finding an effective way to detect resonance in an electrolysis setup that functions like an LC circuit. Let me lay out the full context and details. (The pics are not showing in the post in this order.) Pic 1 shows the flow chart for the setup that is built and based on an auto-tuning circuit designed by a friend, who is no longer working in this area, and is designed to help explore ways to improve the efficiency of Hydrogen production. At this stage, the two gases are not separated but that doesn't affect the way the pulsed supply affects
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