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  • hi gyula.i got a milli amp meter out of an old portable radio cassete.hitachi with 3 scales, record,tuning and battery check.the tuning scale suggests linearity with 0-2-4-6-8-10 on it. to be honest, i don't know if it shows volts or amps or both across 3.9 ohm shunts.or if it accurately compares a chopped input to a ripply smoothed return. i could change the shunts to 2.2 ohms now. a dpdt mmntry switch toggles between measuring flow to t1, and measuring flow down the - return lead.i usually adjust vr1 so the needle sits on 10 measuring input then switch to the return line and note what the meter says.when i started playing with janost's mosfet jt i got back 5-6 doing this.now it nudges the 9 with this test with this circuit.if it's measuring just volts or just amps then i guess the return is more like .9 sqared,roughly 80% back which is still a long way off showing a profit.i'm keen to try coil shorting and other forms of parametric variation with it.i mainly run it on low voltage,1 to 9v. it might go better with more v, or a resistor between the collector and drive coil.lots of options. my gear is pretty crude and more experienced people here are welcome to comment on my methodology.

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    • Originally posted by hotrod68r View Post
      hi gyula.i got a milli amp meter out of an old portable radio cassete.hitachi with 3 scales, record,tuning and battery check.the tuning scale suggests linearity with 0-2-4-6-8-10 on it. to be honest, i don't know if it shows volts or amps or both across 3.9 ohm shunts.or if it accurately compares a chopped input to a ripply smoothed return. i could change the shunts to 2.2 ohms now. a dpdt mmntry switch toggles between measuring flow to t1, and measuring flow down the - return lead.i usually adjust vr1 so the needle sits on 10 measuring input then switch to the return line and note what the meter says.when i started playing with janost's mosfet jt i got back 5-6 doing this.now it nudges the 9 with this test with this circuit.if it's measuring just volts or just amps then i guess the return is more like .9 sqared,roughly 80% back which is still a long way off showing a profit.i'm keen to try coil shorting and other forms of parametric variation with it.i mainly run it on low voltage,1 to 9v. it might go better with more v, or a resistor between the collector and drive coil.lots of options. my gear is pretty crude and more experienced people here are welcome to comment on my methodology.
      Measuring voltagedrop over a resistor is the best method.
      But you need to invest in a DSO or a good multimeter.

      A DSO is the best option.
      It will show you exactly what is going on.

      Comment


      • Hi hotrod68r,

        I am familiar with those small meters used in old casette players or similar sets. Basically they are normal moving coil meters, their coil's number of turns sets the meter sensitivity together with the inner permanent magnet's strength. So how many micro or milli Amper DC current is able to move the needle or pointer to full scale deflection. And under such condition there is a voltage drop across the coil and assuming no any shunt resistor present, the coil's wire resistance can be calculated from the voltage drop divided by the full scale current. (OF course if you had a digital multimeter at hand, you could measure the coil's DC resistance directly by using the Ohm meter part in the multimeter.) Such small meters had a sensitivity of 200 to 500 uA (microAmper) at full scale, max 1 mA (without any shunt or series resistor of course).

        So if higher current is to be measured with such meter, a shunt resistor should be connected in parallel with it and if a voltmeter is needed from such a meter, then a relatively high value resistor should be connected in series with it. In a radio casette player the mode switch did the job of adding a shunt or a series resitor to the meter as per the function needed.) More info on moving coil meters is here:
        schoolphysics ::Welcome::

        I think you can accept your meter's linearity as good and such moving coil meters normally show average values from fluctuating current values which is also a good feature. To answer your question, such meter measures basically current, it is current which deflects the moving coil in the magnetic field. Of course you can interpret this current as voltage when you consider it as voltage drop across a known resistor caused by that current.

        Now I understand what you meant on "i got a bit more return out of this arrangement", thanks. I also think you have a circuit with a COP of about 0.9 perhaps this could be improved further on by certain 'tricks'. Such 'trick' could be to use the rotoverter principle, what do you think on it? Just by adding a 6 - 7uF capacitor in parallel with the collecting coils, the impedance of the resulting LC tank increases, this may inherently reduces current draw for the transistor because it must 'see' the increased impedance via the other coils, hence can only pass a lower current.
        On a similar thought, a capacitor could also be added to the 2 coils between the transistor's collector and + rail, making it resonant too, either on the same frequency as the other two coils would oscillate with the 6-7uF (or maybe on a harmonic frequency, this would connect to your parametric variations?). You mention coil shorting which sounds also good, hopefully the energy needed for controlling the switch would be less than the gain received from it.

        rgds, Gyula

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        • I have 4 cable-choke style ferrite slugs and I will build a Kapanadze style transformer with them in a row.

          We will see how it works

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          • hi janost and all. i got this from another thread on this forum.the contributor said that it had been running for months and recommended having 2 bats in series,driving the circuit with b1 and return going to both.then b2 was said to drive a smallish load indefinitely.(not sure about a reed switch lasting indefinitely though).
            Attached Files
            Last edited by hotrod68r; 07-06-2013, 03:45 PM.

            Comment


            • hi gyula. thankyou also for your input and the merlib rv. pointer. i read "cancelling lenz laws-methods", overunity.com. wondering if synchronous rectification with mosfets, or something like it could replace the diodes and/or could a transistor be timed to play with coil shorting in my current setup to reduce the deficit ? cheers.
              Last edited by hotrod68r; 03-25-2013, 03:31 AM.

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              • hi janost and all again.a bloke called graham maynard has an article on the net called the spin field ferrite sleeve antenna.it's a bit long winded/self indulgent and seemingly off topic,(bit like me) he states that the magnetic field/flux tends to localise around a short coil on a long ferrite rod, compared to say an iron bar. if your planning to have short winding lengths relative to the length of the core it might be something to read and evaluate. he prefers to think of 'radio waves' as particles/photons and suggests that hollow sleeve ferrites work better than solid rods at radio frequencies.and explains why.
                Last edited by hotrod68r; 03-27-2013, 12:01 AM.

                Comment


                • Originally posted by hotrod68r View Post
                  hi janost and all. i got this from another thread on this forum.the contributor said that it had been running for months and recommended having 2 bats in series,driving the circuit with b1 and return going to both.then b2 was said to drive a smallish load indefinitely.(not sure about a reed switch lasting indefinitely though).
                  Hi hotrod68r,

                  Thanks for this, it would be a good test to run this setup on capacitors to see how they charge up or discharge... Also the high wattage resistor in series with the reed switch may dissipate valuable power that never gets out to the output I think.

                  Regarding your notice on replacing the diodes with controlled rectifiers (i.e. MOSFETs) I think yes and I will draw a possible circuit for it. But I do believe that by adding a 6 or 7uF poly cap in parallel with your collecting coils may cause a more useful inner LC impedance increase (loaded Q of the tank may get higher) and this may involve higher gain than reducing the diodes losses.
                  Of course, no need for adding the full switching circuit shown in the rv schematic, only to test the 3 capacitors method for energy extraction from the LC tank and this involves adding a single cap in your case, that is all I think. The 3 capacitor ratio as shown insures that the LC tank would not be overloaded by the load from the transistor whenever it is ON.

                  Thanks, Gyula

                  Comment


                  • Originally posted by hotrod68r View Post
                    hi janost and all. i got this from another thread on this forum.the contributor said that it had been running for months and recommended having 2 bats in series,driving the circuit with b1 and return going to both.then b2 was said to drive a smallish load indefinitely.(not sure about a reed switch lasting indefinitely though).
                    Yes, I'm also experimenting with a dual battery setup at the moment.

                    It improves the charging because the charged battery is not under a load.

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                    • This is ingenious.
                      Why didn't I think of this before?

                      When the coil charges it does so from the left battery only.

                      When the coil kicks back, it drives current through the diodes to both batteries and balancing the charge between them
                      Attached Files

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                      • If I dont get any balancing between the batteries they may need to be connected in parallel with one connected to the diode on the gate?

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                        • This works extremely well.

                          I started with the left battery at 3.62v and the right battery was at low level of 1.55v
                          The left battery is still at 3.62 and the right one has climbed to 1.7v

                          Comment


                          • Originally posted by janost View Post
                            If I dont get any balancing between the batteries they may need to be connected in parallel with one connected to the diode on the gate?
                            You do not readily get balance between the two batteries because the run battery first loses charge and receives it back from part of the collapsing field so ideally it stays on level but the other battery continuously receives charge and does not lose in this process.

                            What counts it can only turn out on the long run: will the run battery gradually lose its charge or stays on its starting level? This is a long process to test, you may wish to use high value capacitors instead of the batteries to speed up this.

                            Gyula

                            Comment


                            • Originally posted by gyula View Post
                              You do not readily get balance between the two batteries because the run battery first loses charge and receives it back from part of the collapsing field so ideally it stays on level but the other battery continuously receives charge and does not lose in this process.

                              What counts it can only turn out on the long run: will the run battery gradually lose its charge or stays on its starting level? This is a long process to test, you may wish to use high value capacitors instead of the batteries to speed up this.

                              Gyula
                              If you look close at the schematic the collapsing field is across both the batteries in series.

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                              • Oops, you are right, I disregarded the diode on the left for a moment...

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