Spark-gap + Step-down-transformer = OU?

[7imix]

Your secondary should measure no voltage before you open the switch. Yet you have that cliff you mention before it starts oscillating. I'm a bit confused about that.

Me too.

[broli]

Me too.

I think it may be sort of logical. We talked about instant momentum transfer (again, momentum being flux here) which causes a similar almost instantaneous jump in current like initial concept this thread started with. Basically if you had no cap and only a load you would see a very fast rise in voltage and then a gradual decline. So you can also try with just a resistive load and see what it gives. That and certainly give that bigger cap a try to get rid of any unwanted stuff.

I have a 2 channel DSO myself so when my toroid arrives I'll try to contribute personally and we can compare notes.

[7imix]

I think it may be sort of logical. We talked about instant momentum transfer (again, momentum being flux here) which causes a similar almost instantaneous jump in current like initial concept this thread started with. Basically if you had no cap and only a load you would see a very fast rise in voltage and then a gradual decline. So you can also try with just a resistive load and see what it gives. That and certainly give that bigger cap a try to get rid of any unwanted stuff.

I have a 2 channel DSO myself so when my toroid arrives I'll try to contribute personally and we can compare notes.

Sweet. Thanks. Which two channel dso do you have? What frequency can it measure up to? I want to try overclocking a dso some day.

I drove the coil with a 555/mosfet circuit and it got rid of the anomaly. Somehow the manual switch is producing that waveform. I now see exactly what I expect. When the circuit is closed by the 555 I see a small spike followed by a sloping fall on the secondary with cap, and when the circuit is opened I see a large negative spike followed by an lc oscillation.

Here is a pic of the oscillation I am getting. I'll make a movie soon. The leads on the scope are reversed so the big spike seen is negative-going.



I think I want to rewire the toroid with wire that has thinner insulation so I can fit more turns on the toroid.

[broli]

The DSO is a ATTEN ADS 1022C some specs:

Bandwidth 25MHz
Rise Time <=14ns
Sample Range 500MS/s
Vertical Sensitivity 2mV ~ 5V/div
Sample Rate Real time 500MS/s,
Equivalent 50GSa/s
Scan Time Base 25ns ~ 50s/div
Trigger Type Edge, Pulse, Video and Alternate
Standard USB Device, USB Host, RS-232
Mathematics Add, Subtract, Divide, Reverse and FFT
Display 64k, Full color LCD, 320 x 234
Language Manifold languages
Weight 2.2kg
Size 305*154*133mm

That's a good scope shot. Can you tell us the capacitance you're using, and how high that voltage peak is? And perhaps a comparison to voltage levels with primary only. Thanks.

[7imix]

Thanks for the scope specs. Nice scope.

The cap I used in that shot is 22 nF, I should probably use an even bigger one.

The voltage is not very high since I am running off 5 volts. The spikes off the secondary fluctuated between slightly higher and slightly lower than the primary, but I wasn't taking into account the DC offset. I'll take some more detailed measurements tomorrow.

[broli]

Btw do you actually measure a voltage in the cap when across the primary? Usually this is only when the switch is closed and the inductor is "charging" after it hit the ohmic current limit the cap will discharge over a certain time period through the inductor and remain at 0 volt.

http://www.falstad.com/circuit/

[nilrehob]

The technique proposed in this thread might also work in motor/generators.
Perhaps thats what the Lockridge Device is all about,
and all other self-runners for that matter?
The motor coil shall have higher inductance than the generator coil,
but not by means of number of turns there either,
its the geometry of the coils that matters.

/Hob

[nilrehob]

It's well known that spacing of the windings of the toroids affects the inductance significantly:

I have now had the chance to test the "spacing effect" on a small toroid,
but it does not seem to work this way.
Can you direct me to somewhere where this "spacing effect" is stated or where you got the picture from?
I would like to read more about it.

/Hob

[broli]

I have now had the chance to test the "spacing effect" on a small toroid,
but it does not seem to work this way.
Can you direct me to somewhere where this "spacing effect" is stated or where you got the picture from?
I would like to read more about it.

/Hob

Winding toroid cores

[broli]

My toroid arrived and did a quick experiment without the LRC meter. Used known voltage and resistance in series with both coils and measured the time constant on the scope.

The coil has 16 windings on both close spaced and spread out coil. I included a picture of it.

The calculated insudctance was:
L= 2.208mH for the large coil
L= 2.576mH for the packed coil

These numbers aren't very impressive. The difference could be attributed to length change, but it's so small that any energy gain would be as well. On the other hand the difference could also be due the windings and we are dealing with the same coil irregardless of spacing.

[nilrehob]

My toroid arrived and did a quick experiment without the LRC meter. Used known voltage and resistance in series with both coils and measured the time constant on the scope.

The coil has 16 windings on both close spaced and spread out coil. I included a picture of it.

The calculated insudctance was:
L= 2.208mH for the large coil
L= 2.576mH for the packed coil

These numbers aren't very impressive. The difference could be attributed to length change, but it's so small that any energy gain would be as well. On the other hand the difference could also be due the windings and we are dealing with the same coil irregardless of spacing.

I found the same thing as you did as you might suspect,
still waiting for the transformer though,
hopefully its behaving differently when things are bigger.

/Hob

[nilrehob]

My toroid arrived and did a quick experiment without the LRC meter. Used known voltage and resistance in series with both coils and measured the time constant on the scope.

The coil has 16 windings on both close spaced and spread out coil. I included a picture of it.

The calculated insudctance was:
L= 2.208mH for the large coil
L= 2.576mH for the packed coil

These numbers aren't very impressive. The difference could be attributed to length change, but it's so small that any energy gain would be as well. On the other hand the difference could also be due the windings and we are dealing with the same coil irregardless of spacing.

I got my big transformer yesterday
unfortunately I experienced about the same small difference in inductance on it as well
Hopefully i will get more time to test it next weekend

/Hob

[broli]

Even though this is what reality shows us, it's not very intuitive from the "conventional" point of view. Knowing that a packed coil produces a stronger field, and that a core basically just traps and amplifies this field. Then how is it that in a closed core loop there's no difference in field strength when changing coil spacing? Makes no sense.

Another interesting type setup is simply using two air coils. A short winded coil inside a long winded one. But this would intuitively be rather inefficient due the fact that the flux of the short one doesn't go all the way through the long one.

YouTube - Don Smith replication first step

[gravityblock]

The permeability of magnetic materials can be changed by applying an orthogonal dc magnetic field which is oriented perpendicular to the main flux direction, in this way the inductance of the main coil can be controlled. This method has the effect of lowering the permeability by adding anisotropic of the magnetic material without affecting the linearity of the magnetizing process. The role of dc bias field is like a magnetic valve on the path to control the flux. Can this method work with pulsed DC for the main coil instead of AC?

GB

[broli]

The permeability of magnetic materials can be changed by applying an orthogonal dc magnetic field which is oriented perpendicular to the main flux direction, in this way the inductance of the main coil can be controlled. This method has the effect of lowering the permeability by adding anisotropic of the magnetic material without affecting the linearity of the magnetizing process. The role of dc bias field is like a magnetic valve on the path to control the flux. Can this method work with pulsed DC for the main coil instead of AC?

GB

Yes that would work. But then you also need to account for the inductive energy of the biasing coil.

In fact this process would be easier to do. Perhaps this is the magic part in some OU devices.

If air is also considered a "core" then you wouldn't even need a real core?