Confirming the Delayed Lenz Effect

[MileHigh]

Farmhand:

Yes the mechanical energy is not free.  That comment is often made by the luminaries with respect to a standard pulse motor.  You need to have a mechanical load on the rotor to get mechanical out, so the statement is not valid.  I use the visualization of a "power pie."  The battery source power pie is sliced up into different thickness slices.  Bearings, wind resistance, a generator coil load, etc.  The pie is really a heat pie when you think of it, because in most cases, heat is the end game.  Unless you are charging a battery or winding up a spring or something similar.

For diodes, the forward voltage at the current of interest is your guide to your slicing.

For your drawing in posting #234, two comments.  It should work better if you rotate both rotor magnets by 90 degrees, say north pointing at the spiral coil for both.   Also if your magnetic shield does a full wrap-around of the spiral coil, then you are bypassing flux around both the outside and the inside of the spiral coil.  You don't want to bypass flux around the inside of the coil, because then the coil sees the changing flux, which is what you want to avoid.  So the magnetic shielding would have to be "U" shaped.  In other words, remove the inside corners of the magnetic shields, leaving you "U" shapes that bypass flux to the outside of the spiral coil.  I hope this description makes sense to you without a diagram.

MileHigh

[Farmhand]

Thanks guys, Gyula the rotor drawing is attached. I think i made the projected part of the field more kinda half circle shaped it seems more  out and also wider cogging is reduced but the magnet attraction to the core is more, when I place the generator core it will help to smooth the cogging as well. I thought if I made the field more projected alone like with stacking it would make more noise due to cogging. But it make lots less and goes faster and speeds up quicker. I can speed it up pretty fast now. I think the field is projected more but is wider and more rounded (effectively) the extra magnets don't seem to attract to the core themselves directly. 

Milehigh I think I get what you're saying about the shielding and I think you're right, it might be more trouble than its worth right now. I can't change the way the driving magnets face but I can add some 10 mm cylinder magnets normally magnetized on the rotor maybe. I'll put that idea away for now. Hopefully my wire for new cores will be ready soon.

I did notice that when the frequency duty of my setup gets high the motor coil "current" does not go to zero even though the mosfet is on for 2.4 mS this is an odd discovery which kinda means the motor coil works in continuous mode rather than discontinuous mode as referred to in boost converters. Still the mosfets could run all day switching an amp each and the inductive energy under control. My boost converter is putting some noise in the circuit but not enough to affect the switching. The current through the charging coil looks very good, it rises sharply and drops at the same rate, the motor coil current rises less sharply and drops off quicker but then at almost no current it continues for a bit then drops off again. For now the input voltage is limited because of the 40 volt rated diode in the boost converter.

Cheers

EDIT: I meant to say in the last paragraph that (the motor coil "current" does not go to zero even though the mosfet is only "on" for 2.4 mS), so I changed it, sorry I was tired. 

Oh and also in the last schematic I posted the capacitor (C3) can be connected to the circuit ground with similar or better effect, when it discharges it can only discharge to the voltage level of the supply anyway so it doesn't go below the supply voltage when connected to the circuit ground, only at start up it is less,.

[hoptoad]

I did notice that when the frequency duty of my setup gets high the motor coil "current" does not go to zero even though the mosfet is on for 2.4 mS this is an odd discovery which kinda means the motor coil works in continuous mode rather than discontinuous mode as referred to in boost converters.
snip..
EDIT: I meant to say in the last paragraph that (the motor coil "current" does not go to zero even though the mosfet is only "on" for 2.4 mS), snip..

Try connecting a 100K - 500K ohm or higher resistor between the gate of Q1 and the negative battery supply rail. That may help to determine if the mosfet is switching fully on and off. If the gate voltage of Q1 is floating, that may be the culprit, and a resistor will remedy the problem. (if it is a problem ).

Also, the rotor magnet/s is/are counter inducing a current in one direction through the motor MC1, via D2 D5 L1 and D4. In the circuit you've shown on the previous page, you can pull Q1 out of the circuit, and spin the rotor up to speed by another means, and you will get current through MC1 via the path I just outlined.

I notice also in the same circuit that any collapsing emf from MC1, during off time (from the supply) discharges through the same path.

http://www.overunity.com/11350/confirming-the-delayed-lenz-effect/dlattach/attach/123297/image//

Cheers

[Farmhand]

Try connecting a 100K - 500K ohm or higher resistor between the gate of Q1 and the negative battery supply rail. That may help to determine if the mosfet is switching fully on and off. If the gate voltage of Q1 is floating, that may be the culprit, and a resistor will remedy the problem. (if it is a problem ).

Also, the rotor magnet/s is/are counter inducing a current in one direction through the motor MC1, via D2 D5 L1 and D4. In the circuit you've shown on the previous page, you can pull Q1 out of the circuit, and spin the rotor up to speed by another means, and you will get current through MC1 via the path I just outlined.

I notice also in the same circuit that any collapsing emf from MC1, during off time (from the supply) discharges through the same path.

http://www.overunity.com/11350/confirming-the-delayed-lenz-effect/dlattach/attach/123297/image//

Cheers

Don't worry the mosfet is switching off ok I have a 10 k resistor from gate to circuit ground. I can show the gate signal wave form if you like. If they were not turning off they would be getting warm but they are not. They switch dead clean, they are driven by a TC4420 driver chip. 

The continuous current is because of the coil not fully discharging I think, I need to speed it up a bit more.

Wouldn't it take a south pole magnet on the rotor to induce a current the way you describe ?

The inductive collapse is discharged first into C3 then C3 discharges through L1 back to MC2 (charging coil) in my motor, between the diode D1 and MC2.
I can see the inductive spike go up to about 25 volts for 400 us or so in C3 when the capacitor C2 is at 12 volts.

The shot below shows it with no battery, the spike is only 25 volts but it is in the capacitor C3 and then it discharges to the point at L1-MC2 in my motor, also that cap C3 in my motor is no longer in series with the battery, it's negative is connected to the circuit ground now. 

Cheers

P.S. OH and the current in the motor coil does stop if the motor is not running hard. as you can also see by the attachment. I could run the motor all day with 2 amps input and no heat sinks on the two switching mosfets, they just get a bit warm, which is also evident by the scope shots I think.

The resonant frequency of C3-L1 is 10 kHz it needs to be (higher frequency) and I think I'll use both a bit less capacitance and a bit less inductance, then the coil should discharge it's energy
quicker, hopefully anyway, if not I'll do the opposite. 

EDIT:, actually I just checked and there is a weak south pole between the two north poles, the south poles are very weak though they don't attract anything much but a compass.
Still it might be possible the souths could induce a current that way. The north poles would try to charge the supply I think.

EDIT: 2, ( I was a bit confused the inductive spike charges C3 to about 25 volts when there is only 12 volts in capacitor C2, a fourth capacitor can be placed were L1-MC2 meet and as long as it isn't too big the spike remains. I tried 1 uF there). But it makes little difference because of C3 and L1. Sorry for the confusion, I modified the post to read right. It's a new circuit, I'm still making changes. I've got a much better sketch to explain things, generator coil as well. 

Also below is a shot showing the voltages at the capacitors C2 and C3, and the currents through the coils when running at a reasonable speed. In a way (after the first pulse) C2 is the supply for the motor coil, when running the switch turns on and C2 discharges through MC1, then the switch turns off as the supply charges C2 through MC2 and at the same time C3 is discharging the inductive energy just previously released to it from MC1, into MC2, then the capacitor C2 is charged with a higher than supply voltage ready to discharge through MC1 when the switch is turned on again, because C2 is at double the voltage of the supply and MC2 impedes the current flow, C2 fully discharges through MC1 before any significant current can flow through MC1 from the lower voltage supply feeding MC2. Only 12 volts is applied to MC2 whereas over 20 volts is applied to MC1.

That's how it works in normal operation, and the difference in phase between MC1 and MC2 currents can be used as two driving phases of current. 



..

[MileHigh]

Farmhand:

Note that a pulse motor is primarily a "pulse circuit."  i.e.; You are analyzing what happens before, during and after some kind of pulse event and for a pulse motor it's a regular repeating sequence of pulse events.  The RC and L/R time constants come into play, which you see in your scope captures.  The component values determine what the time constants are, and you could optimize events so that they do what you want them to do and they are presumably "friendly" relative to the expected or measured speed of the rotor.

For example, it might be that energizing the main drive coil "too long" results in it burning too much energy like a resistor relative to your "payload energy" which is the push on the rotor.  The solution might be to go for a coil with twice as many turns and four times the inductance and hence the time constant will be four times as long.  Note you are also using less current to generate the magnetic field because of the turns-squared effect.  If you have a target "end of pulse maximum current," you may need to increase the battery voltage to push the desired amount of current through the coil to overcome the higher inductance also.

This strategy may give you a more efficient drive pulse.  Even through there is more wire and hence a larger resistance, you get "more magnetic field payload bang for your input energy buck relative to your lost heat to resistance."  In other words the coil generates just as strong a magnetic field as a coil with less turns but with less current, and that may be more efficient.  This would have to be confirmed with testing.  When you look at simple 12-volt relays, you can see how fine the wire is and how many turns there are which would seem to suggest that this approach would be worth checking out.  (With some kind of Coil-A - Coll-B comparative test.)

There is one more kind of time constant at play sometimes.  That's when an inductor and capacitor interact like a tank circuit.  You may notice where the discharging coil charges a capacitor in your circuit the voltage and current waveforms become sinusoidal.  It's like just a "slice" of an LC tank circuit in action.  You can see it in the upper-right blue charging coil waveform.

In very general terms, you will notice for coils that the voltage is proportional to the rate of change of current of the coil.  For caps the current is proportional to the rate of change of voltage.  You can see this in your own waveforms.

MileHigh