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First output coil testVideo demo: https://youtu.be/9ybgmyOsFdM
Luc I saw on the scope that the peak voltage across your primary coils?? was some volts below your feeding voltage so some power loss is hiding somewere.In my over unity contraptions I have to use a higher reisistance value to the resistive load, than the resistance giving maximum power, to come above the ingoing power. And a short circut (or open) output barely affected the input parameters. Regards Arne
I tried posting some technical comments on Luc's clip but he deleted them right away and accused me of trolling. It must be miserable to live in an Orwellian nightmare sometimes, sort of like the movie Fahrenheit 451. So let's break out of the straitjacket and actually use our critical thinking skills and rebel against the thought-control oppressors that want to stomp out free thought and burn books, much to the chagrin of Luc.Here you go, think free and live free or get zapped by a discharging inductor:So you have done the build and you have the working code to energize the coils to make a rotating magnetic field. So now it all comes down to basics. The energizing coils will put flux through the stationary rotor. Naturally when the coils that line up with the stationary rotor are energized, then more flux passes through the stationary rotor. By the same token, the coils that do not line up with the stationary rotor put zero or very little flux through the stationary rotor. Makes sense, correct? So when the Arduino energizes these coils that don't line up with the stationary rotor, that represents the burning of input power with no real output power. It represents power being poured down the drain and all that it really does is heat the coils. Let's say for the sake of argument you are losing 1/4 of your input power to heat because of the energizing of the coils that don't line up with the stationary rotor. You have enough experience under your belt such that I don't think that you are going to disagree with me on this critical point. Pierre has already said the classic line, collect the back-EMF pulses from all of the coils. You have been though that exercise 100 times by now, and you know there is no magic there and you are not even close to considering changing your H-bridge setup to collect back-EMF pulse energy into a capacitor. That's a dead horse that you have seen too many times by now such that you can almost do it in your sleep.So let's talk about the output now. You have a coil wrapped around the stationary rotor and that is where you get the output from the device. So we are talking about the basic nuts and bolts of a generator here. The more turns you use for the output coil, the higher the voltage output. And of course the higher the total resistance of the wire. The more turns you have, the higher the voltage, and therefore the higher value of load resistor the output coil can drive. In general terms, let's suppose that you wrap enough turns where the wire resistance is 10 ohms. That implies that you will get the most output power when you have an impedance-matching load resistor of 10 ohms. However, a note of caution here in the sense that the 10-ohm coil will also dissipate the same amount of power as the 10-ohm load resistor, which means right away that you are only 50% efficient in getting output power from the coil. If you increase the load resistor to say 30 ohms, you will get less total output power in the load resistor, and less dissipated power in the 10-ohm resistance of the coil, giving you a more efficient coil-to-load resistor output power efficiency, but less total output power. So what's the take-away? The take-away is to experiment with different load resistors where the load resistor is less than the coil resistance, equal to the coil resistance, and greater than the coil resistance.So this glorified Arduino setup with the fancy rotating magnetic field is doing on primary thing - putting changing flux through the stationary rotor. When you wrap a coil around the stationary rotor and have no load resistor you are seeing the pure EMF being generated by the output coil. That EMF waveform represents the rate of change of magnetic flux through the stationary rotor with respect to time. Also known as the first derivative of the flux with respect to time. I don't know if Luc's DSO has an integration function. Why do you want the integration function? The answer is that if you integrate on the EMF waveform then you will get a waveform for the actual amount of flux that is passing through the stationary rotor from the Arduino setup. Even if you don't have an integration function in the DSO, you can do it by hand on paper. Why do you do it? Because it is interesting to know how much flux is passing through the stationary rotor.Let's discuss the output when there is an appropriate load resistor. When there is a lot of current flowing through the load resistor that means that the stator coils that are lined up with the stationary rotor are doing real work, and there should be a corresponding increased current draw when those coils are doing work. That implies that when you scope the current draw for the whole device you should see lower current draw for the stator coils that don't line up with the stationary rotor (the "dead" current draw that does nothing but heat the stator coils) and increased current draw for the stator coils that do line up with the stationary rotor.Wrapping more turns around the stationary rotor will NOT give you more output power. That is just an old wives' tale. The amount of power you can extract from the stationary rotor is dependent on the amount of changing flux that passes though the rotor, not the amount of turns. The amount of turns determines the best value for the load resistor, that's all.So, let's ballpark the maximum output power to input power efficiency for this device. I have already stated it above. It's roughly 75% efficient for the stator coils because half of them are "dead" and do nothing. I am saying this because the unloaded stator coils that do nothing will actually draw very little current, and I am bundling in all of the H-bridge overhead. Then we know on the output coil side when you use an impedance matching load for maximum power output the efficiency is maximum 50%. So the ballpark efficiency will be 0.75 x 0.5 = less than 37% efficient.That's a lot of spicy meatballs worth of work with no secret spicy meatball sauce in sight to get less than 37% efficiency.
Hi LucI saw and translated Pierre's reply on your newest video he was asking what are you doing with your coils "return" and said this is the secret if you want it to work.So will guess he means the backemf/recoil/flyback diodes...
Those voltage readings are 2 of the Arduino outputs triggers to the H=Bridges. They are there for reference.Luc
Hi Gotoluc,How did you connect the L298N boards, as H bridges, or as half bridges?RegardsL192
I achieved a reasonable rotor output waveform until I pushed the setup too hard at about 4A per half bridge. This was after about 20 mins of running. This took out at least 5-6 boards, after one L298N exploded. No heatsink was over about 40 deg C.