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  • Power supply unit

    Good day,
    Maybe someone here can help me a little bit....
    I need a power supply to lower the voltage from 230V to 100VDC or 110VDC while being able to modify the current however i please, say from 5A to 36A.
    Please point me in the right direction.
    I want nothing to do with transformers. I could have made one with magnetic shunt but i would have complicated things i think.... Anyway, that's not easy for me as i need the core.

    Thank you,
    Last edited by Buddhafollower; 06-04-2019, 07:25 PM.

  • #2
    I think i will connect in parallel 4 modules with BAT41-800B Triac and set all of them for 100V with a fixed resistor. This will be for voltage control. One of them for 230V supports up to 18A so all four of them should be enough to give me 36A in 100V. Not an expert in electronics
    Then i have to come up with a system to control the current...
    Last edited by Buddhafollower; 06-04-2019, 08:06 PM.

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    • #3
      Ok

      Maybe not?
      Look at some manufactured
      items and there entire build.
      Is there anything that works
      into your area of build?


      See I donít bite much.
      Attached Files

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      • #4
        So basically they work with almost the same circuits and they don't even give the high current (36A) i need. I think my idea is better and cheaper than buying from ebay. Less problems to face....

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        • #5
          I thought about this a bit and i think i will use a saturable reactor as a magnetic amplifier to control the current once i am done with the high voltage part.

          Comment


          • #6
            May I watch?
            I want to understand what you are building.
            Please post photos.
            💡
            🍔

            Comment


            • #7
              Energy Frequency Vibration

              Just change the frequency and go from there.

              Comment


              • #8
                you say you need to change the current,
                this will change the output voltage, any idea what the voltage range is ?
                or do you want 110V only and the current adjusts to keep your 110V ? (not what you said you wanted, but it would help to know what your load is (inductive?, resistive ?))

                what I use for this sort of thing is a variable transformer
                https://www.popsci.com/diy/article/2009-10/what-variac
                I have one that is quite large, they come in all sizes.
                but you can only change current by changing voltage, just not sure that is what you are looking for.

                Comment


                • #9
                  @space I want to keep my 110V but to vary the current from 1A to 36A.
                  I use this for a resistive load such as a 50 plate Hydroxyl generator. (HHO gas)
                  As i said i think i will use a saturable reactor. These things are awesome when it comes to controlling large currents with ease and very low direct currents. With a maximum of 100mA i will definitely be able to control 36A.
                  Last edited by Buddhafollower; 06-05-2019, 05:55 AM.

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                  • #10
                    a variac with a bridge rectifier on the output should likely work just fine, you set current by changing voltage a bit. just watch voltage and current at the same time (you might need a few meters to see what is going on)
                    but there are other solutions that are more precise.
                    not many things are set up to regulate current, and the few that are are usually limited to something like 40V (like the LM2596, one of my favorites), you can add external transistors to increase the current range, but a bit more work to up the voltage range.
                    seems like you might end up needing one regulator for the low end range and another for your high current tests.
                    do you have any tests so far with simotanious voltage and current readings so you can see the impedance of your test ?
                    if you have a few data points you can extrapolate and will get a better idea of what is the best solution.

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                    • #11
                      thought about your answer for a bit longer,
                      your load is resistive, but likely not linear with voltage
                      with resistive loads you can change current by changing voltage.
                      changing voltage a bit is way easier.
                      but if the resistance gets lower when you have more current through it, then it is very hard to set current by using voltage. if this is the case, then a variac is not going to work very well.
                      not many switching power supplies are set up to regulate current only, so, hopefully your test does not need that.
                      then I wonder if you are trying to set your voltage to 110V absolutely and do something like pulse width modulation to set the average current ?
                      I only ask this because you say you want to keep the 110V, and there are limited ways to do this into a resistive load.
                      potentially a transformer and a light dimmer circuit would be just what you are looking for, each not that hard to get or that pricy.
                      but depending on the details, it might be custom electronics that are much more.
                      I suppose I am likely over thinking this, but I don't know just what you are trying to do with your electrolysis generator, so still to many options seem likely.
                      if you would like, I can tell you all the options. but it is lots of typing, so I will wait to see your reply.

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                      • #12
                        @space As i said i want nothing to do with transformers or variable autotransformers. What i want to do is simply keep the 100-110V and play with the current a bit, from 1A to 36A. I know i can change the current by changing voltage but this is not going to work with this installation. Whevener you go below 1.24Vdc per element, you won't be able to generate HHO gas. On the other hand if i don't decrease the current say to 20A i won't be able to run my machine 24h/day 7days/week. The machine will simply get too hot after a while if the maximum current will be at 36A.
                        So a transformer or variable autotransformer are out of the question here.
                        A transformer with magnetic shunt would have been great though but nevertheless it is too heavy a component...
                        I like what you said about a PWM but i know no schematic that will allow me to get this current and voltage. Maybe you can help
                        The few active components that those dimmers have would make them ideal circuits for my project. I would like to just connect 4 or 5 of them in parallel for 36A and then use a saturable reactor as a magnetic amplifier to control current with a small DC voltage. The smaller the number of active components, the better and more reliable the circuit.
                        I kinda hate nowadays active components.... the companies should have perfected them. Such components are quite disgusting to say the least. You have to handle them like you handle eggs....
                        Last edited by Buddhafollower; 06-06-2019, 07:18 AM.

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                        • #13
                          if you want no transformers at all, I assume this means that all inductive components are not ok. this means that every switching power supply is not allowed as well.
                          so you are only left with pulse width modulation (this is what light dimmer circuits do) or the one where your pulses are fixed width and only change frequency (forget the name they have for that)
                          you are maybe also left with using a resistor, but that changes voltage.

                          as far as circuits for the pulse modulation, easiest way to do it is to use a signal generator into a very large transistor.
                          I would use the MG300Q1US41 because I have them lying around.
                          your power in would have to be rectified to DC before you feed it to the transistor.
                          but even then you are likely going to need an isolation transformer to power the signal generator...
                          at least you will if it does not have it built in...
                          anyway, outlawing transformers makes design quite hard.
                          is this entire thing battery run as well ?
                          after all your house is powered by a transformer
                          running it all off of batteries would let you get away from transformers entirely. I don't see any other way to totally avoid them.
                          guess I don't know why you don't want transformers, so it makes it hard to figure out what is allowed or is not allowed.

                          if you do try light dimmers in parallel, remember that semiconductors have lower impedance when they heat up, this will cause one of them to take all the current and destruct.
                          so you have to put resistance in series with each unit so they current share without melting.

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                          • #14
                            @space Please, don't get me wrong, i want nothing to do with transformers because THEY ARE HEAVY, it is hard for me (no, actually very hard) to get the proper core so i will avoid chinese crap and they are really expensive and quite difficult to manufacture. Trust me i wound many in the past. Now i'am 26 y.o. but i wound my first trafo. when i was 17. From time to time, once in a blue moon i have to make my own.
                            I have no problem with a separation trafo. as long as it is a small one just for the signal generator.
                            -Yes, the cell is able to run from battery assembly as well.
                            -This circuit/installation has no problem with inductive components at all.
                            -Same with big resistors, i want nothing to do with them.
                            -It is not that i don't want transformers, i simply don't want POWER TRANSFORMERS. At 3600W the core will have to be heavy, voluminous, almost like the core of a welding trafo.

                            ''if you do try light dimmers in parallel, remember that semiconductors have lower impedance when they heat up, this will cause one of them to take all the current and destruct.
                            so you have to put resistance in series with each unit so they current share without melting.''

                            - I don't know what to say about this... the semiconductors here are triacs, not BJT's. MOSFET's also don't need resistors in series, only bjt's need resistors in the emitter and base.

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                            • #15
                              ok, I see, no heavy components...

                              my guess is that the easiest way to get what you want is to pulse your 110V

                              try the light dimmers first as they are low priced.
                              as to the question of if they need small resistors to current share in parallel, seems as if many others don't agree there as well. here is the first debate I found. https://electronics.stackexchange.co...ving-same-load

                              and if that does not work, try a large power transistor connected to a signal generator that has DC offset. like this one https://www.amazon.com/Koolertron-Pr...dp/B07596133Q/
                              I have an older version of that one and it will directly drive a mosfet or IGBT (just set it for a square wave and something like +15V at the top peak and -15V at the bottom)

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