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Author Topic: Confirming the Delayed Lenz Effect  (Read 870227 times)

TinselKoala

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Re: Confirming the Delayed Lenz Effect
« Reply #1305 on: May 03, 2013, 09:36:54 AM »
Yep.
The MoI of the rotor can usually be calculated quite accurately from the geometry and the material densities involved, and then the power dissipation required to turn the rotor at any given RPM can be determined by timing unpowered rundowns. A chart recorder (or a modern DSO that has a long-duration "chart recorder" mode)  is a definite asset for this kind of work.
http://www.youtube.com/watch?v=PJavCZX_-PI

Alternatively, a known load like a model airplane propeller can be used to determine the power dissipation.
http://www.youtube.com/watch?v=2koW-oC5hJs

MileHigh

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Re: Confirming the Delayed Lenz Effect
« Reply #1306 on: May 03, 2013, 09:39:22 AM »
If somebody wants to be really adventurous there is an interesting observation they could try making on their scope.

You pulse a coil and you can observe the exponential rise in current through the coil.  Nothing new there.

But can you see something different happening when you pulse a coil to keep a rotor turning?  The answer is yes, you should see that the current rises more slowly than expected - possibly??? - or possibly something else happens.  Note that the instantaneous voltage across the coil times the instantaneous current though the coil is the instantaneous power being pumped into the coil.  And the instantaneous power over the time that you are pulsing the coil represents the total energy you put into the coil.  That's the energy that you see when you get the back-EMF spike.  Or is it?

You know intuitively that when the drive coil is making the rotor turn, that means that the coil is exporting energy and transferring that energy into the spinning rotor.  Therefore, you have to expect that when you pulse the coil and pump power into it, and the coil is driving the rotor, that _some_ of the instantaneous power must be going into the rotor, somehow.  Can you observe this phenomenon with your scope?

So since you know that the coil is exporting energy to the rotor, that means that something must be different in the current waveform for the coil when it is driving the rotor.  You know this because the voltage waveform is a constant, so the current has to change.  Again, can you observe that on your scope?  Is there a way for you to develop a test that definitively shows that the the waveforms that you are observing for the coil clearly show that the coil is driving the rotor.  It's almost like there should be some observable "phantom" energy that you put into the coil, but you can't get it back in the back-EMF spike because some coil energy made the conversion over to rotational mechanical energy in the rotor.

Just some ideas in case anybody wants to open up some new territory.

MileHigh

Farmhand

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Re: Confirming the Delayed Lenz Effect
« Reply #1307 on: May 03, 2013, 09:54:14 AM »
If somebody wants to be really adventurous there is an interesting observation they could try making on their scope.

You pulse a coil and you can observe the exponential rise in current through the coil.  Nothing new there.

But can you see something different happening when you pulse a coil to keep a rotor turning?  The answer is yes, you should see that the current rises more slowly than expected - possibly??? - or possibly something else happens.  Note that the instantaneous voltage across the coil times the instantaneous current though the coil is the instantaneous power being pumped into the coil.  And the instantaneous power over the time that you are pulsing the coil represents the total energy you put into the coil.  That's the energy that you see when you get the back-EMF spike.  Or is it?

You know intuitively that when the drive coil is making the rotor turn, that means that the coil is exporting energy and transferring that energy into the spinning rotor.  Therefore, you have to expect that when you pulse the coil and pump power into it, and the coil is driving the rotor, that _some_ of the instantaneous power must be going into the rotor, somehow.  Can you observe this phenomenon with your scope?

So since you know that the coil is exporting energy to the rotor, that means that something must be different in the current waveform for the coil when it is driving the rotor.  You know this because the voltage waveform is a constant, so the current has to change.  Again, can you observe that on your scope?  Is there a way for you to develop a test that definitively shows that the the waveforms that you are observing for the coil clearly show that the coil is driving the rotor.  It's almost like there should be some observable "phantom" energy that you put into the coil, but you can't get it back in the back-EMF spike because some coil energy made the conversion over to rotational mechanical energy in the rotor.

Just some ideas in case anybody wants to open up some new territory.

MileHigh

I agree MileHigh and thanks for the info Tinsel, I have done a rough test to show less energy recovered when a rotor is loaded more, more load on the rotor less energy recovered. The coil does give energy to the rotor, the rotor does not get spun with no expenditure of energy after recovery even considering losses in other areas like diodes and resistance.

I can show on my scope with this motor that when I put the charging coil in place the voltage it produced into the cap for the drive coil is less, just a bit but it is clear. I'll find the video and note the time of it. I did show it I think. People don't see it though. The recovered energy is less because the coil gives energy to the rotor.

Cheers

MileHigh

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Re: Confirming the Delayed Lenz Effect
« Reply #1308 on: May 03, 2013, 09:57:19 AM »
Farmhand:

The person you quoted:

Quote
But I was told that there is a delay because of the inductance, I was told that for a small period as the magnetic field is building there is no current leaving the coil but there is current entering the coil.

That's a metaphysically wrong statement.  Current entering one side of the coil is equal to the current leaving the other side of the coil.

I will mention this and you might get the analogy (I have said it a million times before).   A coil stores energy.  A flywheel also stores energy.  So imagine the current through the coil is going around in circles through the coil.  That's just to help you remember the analogy:  The current flow through a coil is analogous to the the rotational speed of a flywheel.  Then part two of the analogy is that the voltage across the coil is like the torque on the flywheel.

Then for dramatic effect:  The analogy is absolutely real, they are essentially identical.

So, any circuit that you can dream up with a coil I can explain to you how a flywheel can fit into that circuit.  (We are excluding transformer coupling between coils here, but everything else is fair game.)

What this really means is that an inductor is juts an electrical version of a flywheel, and by the same token, a flywheel is just a mechanical version of an inductor.

This takes the "magic" out of coils and brings them into the real world.  Anything a coil can do a flywheel can do, period.

If you are lost and you can't make the connection or envision a thought experiment, then let me give you a starting point.  What about the infamous back-EMF spike.  How the hell does that relate to a flywheel?

Please think about it for a few days.

MileHigh

Farmhand

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Re: Confirming the Delayed Lenz Effect
« Reply #1309 on: May 03, 2013, 10:05:21 AM »
OK found it, from 7:20 in the linked video, first we see the cap voltage at 23.6 volts, then I move the charging coil away from driving the rotor and the cap voltage increases
to 26 volts at 8:06, the pulse width remains constant, but the rotor slows when the charging coil is moved away and the cap voltage rises. When the charging coil helps to drive the rotor energy is transferred to the rotor by the from coil/core/field.

http://www.youtube.com/watch?v=w1_KlgJ09Bs&list=UUBXqDE_ub_PAQRA9LfStmtA&index=4

Cheers

P.S. This is the waveform from my current setup at low speed with double pulses. I have changed the circuit a bit so that the charge battery is in series with the charging coil after the diode. It discharges into two levels looks like. Just looking at one event waveform. Can you see what is happening ?

conradelektro

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Re: Confirming the Delayed Lenz Effect
« Reply #1310 on: May 03, 2013, 12:10:22 PM »
@Conrad: Why in the world are you using a P-channel mosfet in that circuit? The equivalent or even better rated N-channel mosfet would be cheaper and more "logical" in that single-transistor "high side switch" circuit, wouldn't it?

@TinselKoala: your statement made me think and try a N-Channel MOSFET with my Hall sensor.

( Version 1 of my ring magnet spinner, see e.g. at http://www.overunity.com/11350/confirming-the-delayed-lenz-effect/msg359105/#msg359105 )

My Version 1 of the magnet spinner works also with a single N-Channel MOSFET, but it is slightly less efficient because the Hall Sensor is about 55% High and 45% Low per turn of the ring magnet. So, in the N-Channel version the current flows a bit too long (in comparison with the P-Channel version).

But in practice that does not matter much, one would use the N-Channel MOSFET because it costs less and has a lower on-resistance.

I also played with a trigger coil:

The MOSFETs are not suitable for a trigger coil because they need up to 5 V at the base to switch on completely. It works with a trigger coil, but only at high rpm and the thing is difficult to start. I have to try a trigger coil with an ordinary NPN transistor (which switches on e.g. at 1 Volt at the base).

Greetings, Conrad

TinselKoala

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Re: Confirming the Delayed Lenz Effect
« Reply #1311 on: May 03, 2013, 01:31:27 PM »
@Conrad: thanks for the response and the experiment... but....
The N-channel mosfet is usually installed with the drain towards the positive rail and the source (source of electrons) to the negative rail. In other words, use the bottom schematic, not the top one, but put the N-ch mosfet in with the Source pin to the negative rail and the Drain pin to the low side of the load, and the high side of the load to the positive rail. The mosfet, when on, will conduct in both directions, but you may see a difference in turnon times with the arrangement I suggest. I doubt if it will make a significant difference in your pulse motor, but it's normal practice with N-ch mosfets to connect the Source pin to the common negative (ground) rail of the circuit.
The 5.6 K pullup resistor value may also be increased, or even changed for a pull-down (connect to negative rail instead of positive) for significant effects on the circuit performance.  I usually use a pulldown, connecting the gate to the source right at the mosfet pins with a suitable resistor like 100K.

ETA: Never mind, I'm seeing things again I guess, since the bottom diagram now looks correct to me. But consider the resistor function and experiment with a pulldown instead of a pullup.

Also, you could use a bipolar transistor with a pickup coil and use its output to trigger the mosfet...

Farmhand

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Re: Confirming the Delayed Lenz Effect
« Reply #1312 on: May 03, 2013, 02:12:43 PM »
Sorry Mags I know you only want to help. OK guys, this is the arrangement of my motor circuit, showing the current sense resistors I have in place at the moment. Any suggestions ? I'll need to scope the current into the coil at the same time as I scope the drain waveform I guess ?

To explain the operation, after the first pulse the charging coil discharges into C2 which charges it to about 20 volts when 12 volts supply is used, then on the next pulse the capacitor C2 discharges through the motor coil, then the charging coil recharges the capacitor C2 and the cycle repeats. So the charging coil is lagging in phase to the motor coil and the motor coil supply (C2) goes to almost Zero volts, if I use a snubber there it will try to charge the capacitor C2 which is at zero volts and that is no good, it doesn't work well like that.

In the circuit how it is configured now when the motor coil is discharging it still aids to charge the capacitor "C2" because the charge battery is in series with the charging coil then C2, doesn't it ? That is where the charging coil discharges into. But if I try to connect directly the flyback diode to the capacitor C2 or even directly to the charging coil some performance is lost. I've already done the experiments but informally. Mags I can show you if you wish.

The drawing might explain help explain the wave form shown above.

Cheers

P.S. I wasn't able to draw a 45 degree coil quick enough, so I drew it how I made it originally before I used the charging coil to aid the rotation, and showed point "A" and "B" for where the charging coil can be placed.

Ok there's the shots, the top two are the snubbed ones with diode connected back to the coil and the bottom two are the way the drawing is. The pulse width remained the same and snubbed the frequency was quite a bit lower as can be seen. My conclusion is it's better to discharge the inductive energy into a higher voltage.

Yellow trace is the current through a 0.1 Ohm resistor (R2) and the Blue trace is the drain of the mosfet with the scope grounds together.

Bottom left shot is a false trigger, I'll try to get a better one and fix the picture. The pulse width is fixed at 3.16 mS and I do not change it, I can video it if necessary.

Oh please note that I had to change the volts per division for the blue trace in the bottom shots from 10 to 20 to fit it in.

My discharge voltage and current wave forms fit together like hand in glove, so Mag's you were right in that way for my setup I think, but it was to my benefit anyway so I'm stoked with the wave forms of the motor, I wonder what the peak currents and power were for the charging/aiding coil.  :) The input power varied very little.

However with the snubber the current in the coil stops immediately.

..
« Last Edit: May 03, 2013, 05:06:38 PM by Farmhand »

conradelektro

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Re: Confirming the Delayed Lenz Effect
« Reply #1313 on: May 03, 2013, 06:39:43 PM »
@Conrad: thanks for the response and the experiment... but....
The N-channel mosfet is usually installed with the drain towards the positive rail and the source (source of electrons) to the negative rail. In other words, use the bottom schematic, not the top one, but put the N-ch mosfet in with the Source pin to the negative rail and the Drain pin to the low side of the load, and the high side of the load to the positive rail. The mosfet, when on, will conduct in both directions, but you may see a difference in turnon times with the arrangement I suggest. I doubt if it will make a significant difference in your pulse motor, but it's normal practice with N-ch mosfets to connect the Source pin to the common negative (ground) rail of the circuit.
The 5.6 K pullup resistor value may also be increased, or even changed for a pull-down (connect to negative rail instead of positive) for significant effects on the circuit performance.  I usually use a pulldown, connecting the gate to the source right at the mosfet pins with a suitable resistor like 100K.

ETA: Never mind, I'm seeing things again I guess, since the bottom diagram now looks correct to me. But consider the resistor function and experiment with a pulldown instead of a pullup.

Also, you could use a bipolar transistor with a pickup coil and use its output to trigger the mosfet...

@TinselKoala: you are not seeing things, I changed the drawing a bit later because I noticed the error with the Drain of the N-Chanenel MOSFET (error was only in the drawing, a copy paste error). I will try the pull down 100K resistor at the base of the MOSFET. But I am not sure whether my Hall sensor needs a pull up resistor for clean switching.

Trigger coil and MJE13007:

I did some tests with a trigger coil (the trigger coil and the two drive coils are identical).

The efficiency is about the same as with these circuits http://www.overunity.com/11350/confirming-the-delayed-lenz-effect/msg359277/#msg359277 ,
but I can go up to 30 V which gives me 10800 rpm for 1.5 Watt.

But the vibrations are very strong at 10800 rpm , so, I will stay at 6000 rpm for future magic coil tests. (The mechanical problems are not easy to solve; one needed to balance ring magnet and axle, the ball bearings have to be fitted very precisely; all this is beyond my skills).

The trigger coil has a draw back. Starting the ring magnet spinner is not easy because the trigger coil needs to generate about 2 Volt to start things going. One can start by holding the trigger coil closer to the ring magnet and then when it span up one places it further away to avoid drag. This is of course not practical, so, a Hall sensor might be better.

I will try the transistor MJE13007 with the Hall sensor (needs a resistor to limit the base current from the hall sensor output).

Greetings, Conrad

conradelektro

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Re: Confirming the Delayed Lenz Effect
« Reply #1314 on: May 03, 2013, 06:54:20 PM »
@Farmhand: thank you for posting the very clear circuit diagram. Interesting, the position of your charging coil corresponds to the optimal position of the trigger coil in my last test (see my above post).

Greetings, Conrad

synchro1

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Re: Confirming the Delayed Lenz Effect
« Reply #1315 on: May 03, 2013, 11:24:49 PM »
Skycollection's new toroid core input comparison:
 
http://www.youtube.com/watch?v=Rfv6sWSk9QY

MileHigh

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Re: Confirming the Delayed Lenz Effect
« Reply #1316 on: May 04, 2013, 01:31:25 AM »
Farmhand:

In your schematic, are the charging coil and the motor coil on the same core?  You have the same designation "MC1" for both coils.

I can only make some general comments.  The lower traces show that when the MOSFET switches off that there is an "orderly discharge" of the coil energy through the D2 diode and into B2.  The upper traces show a near-instant drop off in the current so that is generating a voltage spike across the coils.

Certainly you see the classic exponential rise in the current through R2 and the coils when the MOSFET switches on because of the property of inductance.

I have to confess I see what looks more or less right in the blue traces but by the same token I am confused and am not sure where you have the ground probes.

Quote
To explain the operation, after the first pulse the charging coil discharges into C2 which charges it to about 20 volts when 12 volts supply is used

That's what it looks like and I have no doubt that you observe 20 volts across C2.  Here is the thing to ponder:  Let's say when the MOSFET switches off that there is one amp of current flowing through the charging coil and the motor coil.  Look at the junction of R1, R2, and C2.  By definition, just after the MOSFET switches off one amp has to be flowing through R1 and one amp has to be flowing through R2.  That leaves no current to flow into C2.   Therefore at first look, all of the current that flows through the charging coil has to flow through R1 and R2 and onwards, and it does not flow into C2.

So what I am suggesting to you is that it merits further analysis, if you are up to it.  Trust me, I am not trying to give you a hard time.  It's simply hard to see all of the subtleties.

Here is what I would do if I wanted to figure out exactly what was going on:  I would do the old sensor coil trick.  I would hook up one scope channel to a separate and isolated sensor coil to get an independent timing reference for the cycling of the motor.  Then, you can put the second scope channel _anywhere_ in the circuit.  So your are free from any constraints of where you put your ground probe.  You can look at all of your CSRs, and look at the voltage across C2.  Looking at the voltage across C2 allows you to _derive_ the current through C2 because you know that the current through C2 is simply proportional to the rate of change of voltage across C2.

This is a lot of work, no doubt, and you probably aren't going to go there.  In the end what you can get is a timing diagram that actually describes the operation of the circuit.  You can line up scope captures with some image editing software so that you end up with somewhere between say five and a dozen traces that show you exactly what is going on.  How C2 gets charged up will be answered with that exercise.  I did all this in electronics labs more than 30 years ago.  There is a tangible sense of satisfaction and accomplishment when you do this.

MileHigh

Farmhand

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Re: Confirming the Delayed Lenz Effect
« Reply #1317 on: May 04, 2013, 10:13:45 AM »
The charging coil is a separate coil with a separate core this is clear in a couple of the video's, the MC1 label was a mistake it should be MC2.

This is the way wave form at the Cap C2 looks. I've already showed it. The cap fills to almost double the supply then discharges and refills again.
It's a classic "de-q'd" charging cap wave form.  If there was no "de-Q-ing" diode the 20 volts or so would return to the supply before the next bang if the charging circuit is not at full resonance. It's the same wave form I get at the charging cap of my Tesla coil circuits. And it would be the wave form as would be produced by the Tesla IGNITER FOR GAS ENGINES patent device (if it had a "de-q-ing" diode). The purpose was to get a higher voltage into C2 to dump through the motor coil. I'ts not perfect but it works way better than with just the one Motor coil and the charging coil 12 inches away on the bench. So it's a win win for me. I'm happy to go ahead and develop it further.

(http://i227.photobucket.com/albums/dd168/Toey1/Supplydischargecapacitor.jpg)

In the four shots picture the two scope grounds are together at the motor coil end of R2, one probe goes to the other side of R2 and the other goes to the drain, I've described that as well.

I'd like to go on and make a generator coil but if there is any wave form in particular you would like to see, i'll do it if I can. I'll remove the de-q-ing diode and get a shot from the cap C2 probed at C2 with the ground on the circuit ground, I did mean to do that.

I apologize for editing posts my computer is occasionally shutting down so I gotta save or possibly lose.

I've found a couple of ways to do away with the second battery but none work quite like the battery to give a neat looking current wave form.
The battery has low resistance but has 12 volts of built in "counter emf". I think the only best way is to keep a cap at 12 volts somehow while allowing the spike to build the voltage in the cap then dump it through the charging coil every now and then maybe once every few rotations or something. Or use a small cap so it can be dumped every bang.

Milehigh if you look back in the thread you will find a comparison of the currents through the two coils.


EDIT: AS you can see the cap C2 drops to Zero volts, if the cap C2 is at 20v and the supply is at 12 volts when the mosfet is switched on the current flows from C2 through the Motor coil before the current in the charging coil can start to flow because of C2's higher voltage, there is some time when current flows through both at the same time but the start of the current is delayed in the charging coil. This is evident in the current wave form comparison.

The idea is to use short pulse widths and higher input voltages with the correct LC relationship to secure the correct difference in current phases.

Cheers

..

PiCéd

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Re: Confirming the Delayed Lenz Effect
« Reply #1318 on: May 04, 2013, 12:27:10 PM »
Quote
Skycollection's new toroid core input comparison:
 
http://www.youtube.com/watch?v=Rfv6sWSk9QY

It's apparently a good idea, a coil with a toroid in the middle of.
In other way, I see that the output voltage decrease with the rotor accelerate, the amperage must do the same thing.:(
« Last Edit: May 04, 2013, 02:33:33 PM by PiCéd »

Farmhand

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Re: Confirming the Delayed Lenz Effect
« Reply #1319 on: May 04, 2013, 03:48:24 PM »
Milehigh, Here's the voltage and current wave forms. For the scope shots the yellow is the motor coil and Blue is the charging coil. EDIT: And for the voltage measurements the scope grounds were at the circuit ground the probes at the positive ends of the coils. The thing is there is only 12 volts applied to the charging coil, because of the diode and the the way it works after the charging coil discharges into the cap the positive end of it becomes at the voltage of the charging cap it discharged into. you can see the 12 volts battery voltage applied to it drop slightly under load then rise in volts to the same as the capacitor C2. Because the motor coil has over 20 volts applied to it the current moves quicker and starts just before the charging coil current, the charging coil current ends as is shown in the scope shot 6 mS after the motor coil current ends and looks like the motor coil current starts 12 mS before the charge coil current, (my charge coil has less inductance it should be the same as the motor coil and will be soon). The delay in the peak current seems to be about 12 mS.
We can see the voltage applied is practically in sync to begin with, but the inductor voltage curves down as the motor coil discharges the capacitor C2.

The frequency of the motor was higher when the current wave forms were taken, it was 74.63 Hz. So the phase delay can be calculated from that being there is two magnets on the rotor.

I thought it was obvious. There is a definite delay in the phase of the currents and it can be manipulated by known means and utilized easily enough.  :) Even if there was no delay the charging coil could still aid the rotation, it's just a matter of placement. I'll do some calculations and see if I can find the phase angle delay and such things.

To see the divisions better just download the pic and view blown up a bit maybe if anyone wants to be accurate.

The delay in the phase of the currents is related to the pulse width in a way but also due to voltage over inductance and resistance effects as well as the return current from the discharge of the motor coil.

Well that's all based on if I'm reading the scope correctly.

Cheers

P.S. I got a reading of the phase and shots below, with a duty of 30% "on" time for the mosfet I get a phase difference of 40 degrees which is about where my coil is. The setup is using 400 mA and running at 2500 rpm. I added a 1 uF capacitor between the charging coil positive where the charge current return is and ground to catch the voltage spike as shown.  ;)

..
« Last Edit: May 04, 2013, 06:09:40 PM by Farmhand »