Effect of Recirculating BEMF back into Coil test 2

[deepcut71]

I've seen a similar effect on spherical magnets and Rodin coils.

If the magnet is rotating then a weak electric field would be generated and induced into the coil ?

[spikeychops]

Nice work gotoluc!

Excellent video set, man.

I too am surprised nobody seems to be seeing the significance of this effect.

You are essentially routing the BEMF back through the coil, and in doing so, required approx 25% LESS energy, to do significant work (lifting the heavy NeoMag), which was unable to be done, even WITH 25% more energy in the system! Fascinating.

Is the mag oscillating or still when lifted?

If it's moving enough, perhaps a 2nd coil enclosing the mag would gen some juice?

[spikeychops]

On second thought, what would happen to the magnet, if you were to automate the switch, and switch it at a much higher frequency? Would it oscillate then?

Up and down maybe...then add a second coil , possible a large toroid, and then you have a magnetic generator, which i suspect, due to this effect you've found, put out more energy than it's fed. Might be worth looking into, if not already?

Thanks again, great work.

[gotoluc]

Hi spikeychops,

Actually I could not prove it to lift the magnet higher then using straight DC. When I added the Watts it came to just about the same.

However, I'll keep this trick in mind for some other setup and may find a better use for it.

Luc

[maximumgravity]

Just an interesting observation - when in normal mode, the scope shows the diminishing wave forms - after the spike. Tesla often spoke of these like ringing a bell or releasing tension in a spring - these vibrations setle out as the spring or bell looses its energy until it finally retuns to "neutral" (or at rest). When the BEMF is fed through the coil, those ever dampening spikes completely disappear. Its like striking a bell, and not geting the reverberation - a duck's quack - no echo.

[alientechshop]

could the magnet be adding more power to the coil? the magnet is moving slightly.

[gotoluc]

Hi alientechshop,

no, the magnet has no effect. As a matter of fact, when the magnet is removed the coil is a little more energy efficient.

Luc

[stawmy]

Don't worry, there are plenty of people looking into it!

[BodkinsEnergy]

LOL that is it, why are we not doing this LOL

Thanks son of the father

Love and Light

X

[centraflow]

Good stuff as always Luc. A question does the fet have an inbuilt diode?

[gotoluc]

Hi centraflow,

I'm not sure but if you want to look it up they are IRF840

Luc

[Can101276]

I will quote my last post

" Tesla seemed to imply that the greater the voltage the greater the effect"

[gotoluc]

Hi Can101276,

yes I know and I tested it to over 500 volts but when I calculated the Watts power used for the same magnet distance then using 170 volts it was getting less efficient as the voltage climbed up. Could this be an electronic component limitation?.... I don't know! as I have no way of testing it at higher voltages using a mechanical switch.

Luc

[captainpecan]

This is very intriguing to say the least, but I have a theory as to why there appears to be extra work done now. Pulse 1 enters the coil, the magnet lifts, the field collapses but is immediately regenerated somewhat as the bemf is sent back into the coil. Pulse 2 enters the coil, not allowing the field presently build to collapse completely, it instead builds upon what is there for an even stronger field. Thus pushing the magnet further away, and not allowing as much energy to enter! Maybe...

[captainpecan]

Interesting thought about the current draw decreasing. Is it possible that the bemf discharge, now carries it's own bemf discharge at the exact time a new pulse is trying to enter the coil? Thus restricting the amount of amperage allowed to enter the coil? I think I explained that right, sorta confusing to put into words.

[gotoluc]

Hi captainpecan,

I understand your explanation but I don't think this is happening since there is so much open space between the on and off pulses, about 98% open since the duty cycle is about 2% and at 66 Hz only that makes allot of space.

[gotoluc]

What I think it is the mosfet is having a more difficult time switching off when I don't recirculate the bemf since it is now fighting that kickback but when a diode is before it taking care of this fight then the mosfet is relieved of this task. It is easy for me to confirm this since there is a very large amount of heat at the mosfet when not recirculating but when recirculating 90% or more of the heat is gone.

I hope this make sense to you

Luc

[Drevtoobe]

Hi Luc, that's a great little experiment that you are doing. Some of your posters mentioned that when you switch in the diode you extend the life of the magnetic field and this keeps the magnet levitated. I think that they fundamentaly have got that right. I am mystified by the pick-up coil waveform when the diode is not switched in and will mention more about that later.

[Drevtoobe]

Your description for the effect is a bit misleading and I will explain why. When you are energizing the coil when the MOSFET switches on the current through the coil starts to climb. As you know, the coil is an energy storage device, where the Joules of energy are stored as moving current (or magnetic field, take you pick). The energy is 1/2 L i-squared. When the diode is switched in, the energy stored in the coil discharges through the diode. Do you see what I mean?

[Drevtoobe]

If you follow me, as opposed to "recirculating" the BEMF, you are really DISCHARGING the BEMF. It's akin to putting a resistor across a charged capacitor, you are not "recirculating" anything in the capacitor, you know that you are discharging the cap. So the same thing applies to the coil.

Note that putting a diode across a relay coil is standard practice because you want to get rid of the coil's high-voltage kick-back spike because it could disturb the rest of your circuit.

[Drevtoobe]

Without the diode, the magnetic field collapses almost instantly, and of course that meanse there is less "lifting power" to keep the magnet levitated.

For the mystery of the pick-up coil waveforn, it get's very difficult to visualize everything in your head. Even though what you are doing is fairly simple, a schematic and a timing diagram would help. Lidmotor is the model for that.

Back to the waveform, the longer negative pulse may be a fake-out, it's not really there.

[Drevtoobe]

Here is my current guess: When the diode is not connected, the main coil generates the big very short negative spike at the end of the excitation pulse. The pick-up coil generates that high voltage and then is left in "limbo" because the "primary" side of the "transformer" is now open circuit. The pick-up coil charges the capacitance of scope probe cable. The long negative pulse is the cable cap slowly discharging, then "something" kicks in and it starts ringing. It's just a foggy guess.

[Drevtoobe]

I hope that I can make one more posting. Just in case you are not aware - the length of coax cable for your probe between the between the pick-up coil and the USB scope input is effectively a capacitor, and that is what I think you are seeing discharging through the high-impedance scope input which appears as the long negative pulse. If you can switch your USB scope input to 50 ohms, it shoud disappear. You are changing the scope "resistor" from 1 Mohm to 50 ohms.

[gotoluc]

Hi Drevtoobe,

somehow I knew you would have a field day with this one!

I would tend to agree with most of what you are saying.

So you think the 45" length of my scope probe cable can have this much capacitance storage with a 2% duty cycle at 66 Hz?

That is interesting!... well I'll keep playing around with this to see what else I can find.

Thanks for posting your opinion.

Luc

[captainpecan]

Once again, yet another well put together video and experiment! I've been trying to wrap my brain around these results as well. I too have recirculated bemf, and I also got some results, but not nearly as clear cut as yourself. Thanks for sharing.

[gotoluc]

Hi captainpecan,

thanks for your positive input.

Looking forward to see your results when you can share them.

Luc

[janne808]

Does your usb scope have a integration function. Did you integrate the waveform when you measured with the 1 ohm resistor?

[janne808]

Asking because light bulb's resistance and power has a exponential relationship with voltage. Are you aware of this?

[gotoluc]

Yes I am aware of this. When I observed the on off waveform with my scope it was done using a 10 watts 5% 1 ohm normal resistor and not a light bulb. I used a light bulb in the video because it is a simple test that could be understood by many more people the looking at a scope shot.

Luc

[gotoluc]

Hi janne808,

If my scope has that function I'm not aware or even would know how to use it. I just switched the recirculating diode on and off and it was clear by observing the on off period form that with the diode recirculating it made the mosfet switch off to zero much cleaner, with no recirculating (diode off) the off had a peak and several degrading bounces which could account for the wasted energy.

Luc

[janne808]

Okay. If your multimeter is up to snuff (true rms meter) it probably does this already.

It just wasn't clear if the bulb is really indicating the power level, how it is connected etc. Bulbs are non-ohmic so not a good idea to measure current and power with in general.

[gotoluc]

Yes! the meter used in this video is True RMS.

I only use a bulb as a visual aid to see if its changes are in sync with the meters. I also keep them at minimum glow.

Luc

[janne808]

Alright. That is pretty wild.. like some sort of vortex flow isn't it.

[gotoluc]

Never though of it that way but something interesting is going on.

I have something that I don't quite understand ... if we are elongating or doing something to the coil by recirculating the inductive kickback then why am I not seeing that on my scope shot in this video?... we see the on off with kickback but when I flip the switch to recirculate the kickback it gets consumed but we see no extending of the wave form or anything!... so what is really giving the extra push on the magnet???

Luc

[janne808]

Yes that is weird isn't it. It has to do with the diodes.. I'm not going to get into it that deep but I think the magnetic field just isn't collapsing at all when the diodes are in the circuit.

What happens when the wave cycle and frequency are different to this. I'm guessing you get some BEMF on the scope and the magnet isn't as steady?

[gotoluc]

Hi janne808,

no! varying the duty cycle or frequency makes no change on the effect other then what would be expected, higher frequency is smoother on the magnet then lower frequency, longer duty pushes the magnet up more etc.

Luc

[cenlasoft]

Hi,

Great video. I am having great luck with reproducing your experiments. Keep up the good job.

Curtis

[gotoluc]

Hi Curtis,

thanks and can you post a video to show your results.

Luc

[m3sca1]

excellent demonstration of the effect of lower input amperage-this could apply to the adams motor device i am tinkering with-seeing as it is repelling the magnet with a collapsing field.

thanx gotoluc

5 from me

[harpbloke]

thats brilliant. you could PULSE THE SWITCH and get the neo jumping, like those rough vids of whats his name...jumping coils etc? cant remember, maybe you know? grey??

[harpbloke]

woops, watched your last vid first...youve already done it

[kubikop]

My experiments show this too, well done! Some people can only believe what they were told at school, stick at it. The only thing I think is it is not BEMP it is Flyback voltage. If you don't believe me I can produce links for you to decided either way, but Fly back voltage is what I think we are seeing here.

Well Done and keep experimenting....

Paul..

[janne808]

I think you're right, but the strong permanent magnet adds a little spin to this theory.

Physicists are looking into these sort of things but the physics is still a bit on the air about these issues. Really nice experiment!

[Gintaras]

Thats what BEMF is, "flyback" voltage as you call it.

[kubikop]

If you look them up, they are not the same. :-)

[bartley440]

Check out the online MIT courses on youtube.

Do a search on LET 22 MIT 8.02 and watch all of the lectures and you will see some amazing things!

[Gintaras]

I see you done more experimenting and got more results, great finding!