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Help setting up Bedini SG properly.

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  • Help setting up Bedini SG properly.

    Hello to everybody,

    I would need some adivse/help with my Bedini SG build.
    28" aluminium bicycle wheel
    18 - ceramic c8 magnets from teslagenx on wheel
    7x20AWG+1x23AWG 130' -- prewound coil from teslagenx
    7 - MHl21194g bought from
    7 - Neon-2 bought from
    14 - 1n4007 diodes bought from
    7 - 100ohm 1watt resistors bought from
    1 - 12ohm 10watt resistor
    1 - 1kohm 1watt potentiometer
    magnet -> coil distance - 7-8mm

    My initial issue was that the neon lights didn't light up all at the same time and with same intensity. Some of them were bright white/purple, some of them were very dimmly lit orange. This was solved by adjusting the potentiometer value and now all neons light up at the same time with same orange intensity (approximately -- eye test).
    I now think that something else is wrong with the device.
    It draws approx 120mA at about 90 RPMs. I was expecting to draw close if not over 1A at around 300RPMs.
    Another thing to mention is from post 30 from:
    "When you connect power to the "run" battery nothing should happen. If the neons light up at this point then the trigger is backwards. If nothing happens then it is as it should be."

    I connected the input power to the device (with no output battery connected) and the neon lights did lit up for a brief moment. I though then I connected the trigger wires wrong so I reversed them, but the device won't turn on at all then.
    Attached pictures of the device. 2019-11-22 14.26.11.jpg2019-11-22 14.26.01.jpg2019-11-22 14.25.39.jpg2019-11-22 14.25.12.jpg2019-11-22 14.25.02.jpg
    Thank you

  • #2
    additional pictures with coil and wire descriptions.2019-11-22 14.25.02.jpg
    2019-11-22 14.31.52.jpg2019-11-22 14.32.06.jpg2019-11-22 14.32.30.jpg2019-11-22 14.39.52.jpg


    • #3

      1. Never run or test a JB SSG without the output battery hooked up...! Just asking for your transistors to blow up or be weakened....
      2. Your Neon's should NEVER glow!!!! They are there to protect your transistors from blowing up, and them lighting up says they are saving your transistors from blowing up, but that will not last long, and eventually the transistors will DIE from the high voltage spikes that make the neons glow.
      3. you may have damaged or killed transistors by running it with out a output battery...


      • #4
        Hello RS_,

        Thank you for the input. I did understood that it's not a good idea to run the SSG without the output battery connected. I didn't ran it for very long periods of time... as I did find out that it will quickly burn the transistors. Many cheap MLJ21194G transistors bought from china/ebay burned this way within a couple of seconds. I did however bought the MLJ21194G from the link in first post which seem to be from a respectable manufacturer / original. With these new transistors the SSG can run with the output battery disconnected without the transistors burning themselves within a couple of seconds as it was the case with the cheap/ebay transistors. I had to do this because everywhere where I saw the neon's light up, they lit up all at once with the same orange intensity. I did understood that the neon's are there as a safety bypass and should not be abused. Here is a short movie of them lighting up: // this was with the circuit from the first post before changing the potentiometer value.

        I build a new circuit with new components. The transistors, diodes and resistors were matched as good as I could get with the components bought (same with the previous build).
        Unfortunately it's still the same issue, current draw approx 120mA @ ~90RPMs.
        I just noticed that the 12ohm 10watt resistor I thought I used is actually a 20ohm 10watt resistor. I don't think here is the issue as I did shorted the resistor and nothing changed..
        I use the same potentiometer 1kohm 1watt. Here is a picture of the new circuit build:
        2019-11-26 17.53.44.jpg2019-11-26 17.53.04.jpg
        Do I need maybe another 1kohm 1watt potentiometer?
        Any suggestions are welcome.
        Thank you


        • #5
          I'm thinking things are not right with your trigger circuit. That potentiometer looks like it has too low a wattage rating. If I was going to replace it i would replace it with something like this:

          and then like a 100 ohm 2watt resistor in series with that.

          makes sure to double check you have things connected like the schematic....I'm sure you probably have but just to be sure


          • #6
            Originally posted by daucupace View Post
            I did however bought the MLJ21194G from the link in first post which seem to be from a respectable manufacturer / original. With these new transistors the SSG can run with the output battery disconnected without the transistors burning themselves within a couple of seconds as it was the case with the cheap/ebay transistors.
            Even if they don't blow up with the output battery connected, make sure a battery on the output is connected anyway because you're still straining them even if you don't know it.
            Aaron Murakami

            You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete.” ― Richard Buckminster Fuller


            • #7
              Hi Joster,

              Thank you for the suggestions. I bought this 1k 4w potentiometer:
              since they didn't had any 5watt ones. I also bought a 12ohm 10watt resistor and a separate 100 ohm 2watt resistor for connecting it in series with the potentiometer.

              Hi Aaron,

              Thank you for the information.

              I will report back in a couple of days after I receive the order.


              • #8
                Hello everyone,

                I put the new 4watt potentiometer with the 100 ohm 2 watt resistor as shown in below picture, unfortunately it's still the same issue, low current draw...
                2019-11-29 13.50.00.jpg

                What could I test/change next?
                Thank you


                • #9
                  Just an idea not sure if it will work but it is what i would try next:

                  I just realized you already have 100 ohms on the base of each transister so get rid of the 10w and 200 ohm 2watt and see what happens as you change the pot. Also, i don't think i see any diodes across base/emitter for the transisters?


                  • #10
                    Hi Joster,

                    Thanks for the quick reply.
                    I removed the 10w and the 100ohm 2watt resistor and only the 4w potentiometer and the 100ohm 1 watt resistor going to each transistor base remained, unfortunately the same issue.
                    I begin to wonder if this is how my SSG is suppose to work and the low current consumption is normal... could this be possible?
                    The wheel is a 28 inch bicycle wheel with 18 magnets glued next to the other spoke.
                    The current consumption can be adjusted from ~100mA to ~450mA. Charging the battery at ~170mA current draw @ 115 RPMs does seem to charge better then when the current draw was set o 120mA@ 90RPMs and in the 100 - 200mA range should I find it's sweet spot..
                    There are also diodes for each base/emitter, they are not seen in the last picture because there are underneath the transistors. In the second picture from the first post they can be seen hidden in the background.
                    Thank you
                    Last edited by daucupace; 11-29-2019, 11:02 AM.


                    • #11
                      u could very well be right. what is the resistance of the coil you have? meaning if u put an ohm meter across one of the power windings what do u get?


                      • #12
                        Hi Joster,

                        I get 1.4 - 1.5 ohm for each power winding and 3 ohm for the trigger...seems good to me..


                        • #13
                          Hi daucupace,

                          In studying your photos it looks like you may have some bad solder joints, especially on the base resistors. Use a good heat sink on each component and reheat all your solder joints to make sure you don't have any cold joints. Some appear to have too much solder and others not enough.

                          I noticed in your video very uneven and random lighting of the neons. As others have said, you need to avoid running without a secondary battery attached, but when any of the neons do light up they should all light at the same time with equal intensity and color. Your transistors and/or base resistors are either badly matched or faulty to cause this. Poor solder joints can also cause this.

                          Your Teslagenx coil is not the problem. The power windings are 1.319 ohms each and the trigger winding is 2.647 ohms. I suspect that your ohmmeter is not exactly accurate at these low values. I have 4 different meters and they all give me a slightly different reading at these low values.

                          One other thing that can greatly affect RPM and current draw is good wheel balance and low bearing friction. A well balanced wheel with good bearings should have a run down time of at least 10 minutes.


                          • #14
                            Hi Gary,

                            Thank you for the reply. I rechecked and did reheat some solder joints but I think they were already soldered good in the first place...,some of the solder can not be seen because it flowed under the solder joint which cannot be seen from the pictures... the legs of the resistors and diodes are swirled around to get better/more contact, the ends of all coil wires are cleaned and soldered before soldering them further.
                            I uploaded some close up pictures for better view of the new solder joints, if you see something wrong please let me know. It did not change the low current draw.
                            The uneven and random lighting was solved by changing the potentiometer value. I used the instructions from the book to find matches (out of 40 cheap chinese ones and 14 not so cheap ones) . They were matched with approximate value as best as I could with the ones I got. I understand that you need more than just the instructions from the book to really get matched transistors... They could be badly matched from the start by me but I doubt they were bad in the first place...I did get the same similar low current draw with all the transistors. I don't think it's the coil either. I can get also 2 different readings from my 2 different meters... .
                            The wheel is balanced and some light oil was put in the bearings. It has a run down time of 10 minutes.
                            Thank you

                            2019-12-02 19.36.08.jpg2019-12-02 19.36.52.jpg2019-12-02 19.37.15.jpg2019-12-02 20.00.09.jpg