Confirming the Delayed Lenz Effect

[gyulasun]

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Attached is the circuit I am testing (not finished yet, attention, might not work) and the set up (still without the two Hall sensors).
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Hi Conrad,

Would like to suggest connecting one-one resistor between each Hall device output and the positive rail, like a pull-up resistor, value may be anything in the some kOhm range like 4.7 kOhm to 10 kOhm. These identical resistors would be needed for discharging the p-channel MOSFETs paralleled gate-source capacitance, because there is nothing shown in the schematic to do that.  The Hall devices have an nmos open drain output with a clamping 30V Zener diode in reverse direction to defend the device, so the output pin cannot discharge the inherent gate-source capacitors of the switching MOSFETs. the switch-off time may become very uncertain or even impossible.

One more thing: to make your pulse motor more efficient, you may wish to consider using the magnetic poles at both ends of your relay coil, it would cost input-power-wise the same but  the output torque would increase.  To do this, try to look for low profile relay coils, maybe around max. 1 cm in length only and use two of them: one coil as is shown now at the 9 o'clock position and the other one at the opposite side of the magnet at the 3 o'clock position.  And you would need a C core to connect the outer ends of the relay coils to have a horse shoe like core with the two coils strongly attached magnetically to it at the endings. 
I know that 12V DC relay coils normally have some hundred Ohms coil resistance and this may prove to be high to cause power loss if you consider collecting the energy of the collapsing field at switch-offs.  There are relays operating with 5V DC and these can have coil resistances in the 40 - 70 Ohm range, making less loss, and using two such in series connection to switch them on or off at the same time as if they were a single coil you could use the same switching circuit.  OF course  each of the poles of these coils at the prongs of the C core should be chosen correctly to function as needed for the diametric magnet poles in every moment.

rgds, Gyula

[conradelektro]

Hi Conrad,

Would like to suggest connecting one-one resistor between each Hall device output and the positive rail, like a pull-up resistor, value may be anything in the some kOhm range like 4.7 kOhm to 10 kOhm.

One more thing: to make your pulse motor more efficient, you may wish to consider using the magnetic poles at both ends of your relay coil, it would cost input-power-wise the same but  the output torque would increase.

There are relays operating with 5V DC and these can have coil resistances in the 40 - 70 Ohm range, making less loss, and using two such in series connection to switch them on or off at the same time as if they were a single coil you could use the same switching circuit.

rgds, Gyula

@Gyula:

Thank you for the good advice, that helps a lot.

I would like to ask you, whether you know some good P-channel Mosfets which could be useful for this circuit. The P-channel AUIRF9Z34N seems to be an overkill (can switch a heavy current). I think one could use smaller ones , e.g. for switching only up to 1 Ampere. (N-channel Mosfets would need additional transistors, because the Hall sensor switches from High to Low when activated.)

I have 90 Ohm DC resistance coils from some other relais and will try them as well.

The "horse shoe like core with two coils" is also a very good idea. I have to think about this, because the space around the spinning ring magnet is limited in my set up . Once the magnet is spinning (heopefully very fast) I want to place various generator coils near it to test for DLE (reduced drag and speed increase). Horse shoe + two drive coils + two Hall sensors, where does the generator coil go?

In version two of this spinner I will leave more space around the ring magnet (also below the axle). At the moment I am testing various placements of the Hall sensors. (They should never switch on at the same time. Duration of "on time" is critical for power consumption.)

I have got 10 very good bearings (with ceramic balls) and a collection of diametrically magnetised ring magnets, so I can build several versions. I am thinking about an even smaller rotor (10 mm diameter ring magnet) because theoretically it could spin faster than a bigger one.

Greetings, Conrad

[DeepCut]

New coil has no effect on rotor speed when shorted.

It also accelerates when used as an air core.

All of the details are in the infobox of the video :

https://www.youtube.com/watch?v=e9X7tqNCZqM


Cheers,

DC.

[conradelektro]

New coil has no effect on rotor speed when shorted.
It also accelerates when used as an air core.
All of the details are in the infobox of the video :
https://www.youtube.com/watch?v=e9X7tqNCZqM
Cheers,
DC.

Nice speed! I get the impression that the effect (no drag, speed up) can be produced with any coil as long as the magnet spins fast enough?

(My set up is not finished, many other chores hold me up.)

Greetings, Conrad

[DeepCut]

Nice speed! I get the impression that the effect (no drag, speed up) can be produced with any coil as long as the magnet spins fast enough?

(My set up is not finished, many other chores hold me up.)

Greetings, Conrad

I think not any coil, but any coil of many turns.

Capacitance seems to be the key, as we drive an inductor at higher frequencies it behaves more like a capacitor.

The last time i wound a coil of this size it didn't perform so well due to it's inductance, which is also governed by it's physical dimensions not just the number of turns, but it put out 1,100 VAC. It gave me a terrible electric shock when i mishandled it, right across my chest and made me yelp !

I want to see how it does when i step down the voltage, if that works then the next step is multiple coils.

Unfortunately it costs me around £40 to make the coil!


All the best,

DC.