Back EMF vs. Collapsing Magnetic Field Spike

[sucahyo]

Step 1: Replace batt being charged with cap

Measure energy from driving batt, compare with energy showing up in cap; energy in cap is smaller than energy drawn from bat.

Step 2: Coil is wound as 2+1

Do the same measurement; energy in cap is bigger than energy drawn from bat.

In case of Joule Thief Using mobius coil 1:1:1, 1.5Volts battery two 2N3055, the difference between LED brightness is not noticable. Different transistor base resistance also tested, LED will be dimmer or brighter on both output equally.

YouTube - Third winding for radiant oscillator?




about time compressed, is it another way of saying a very sudden high potential rise and fall?

[nilrehob]

3. You disconnect the power and you get the spike.

That IS the forward EMF.

Flyback diode - Wikipedia, the free encyclopedia

Induction at the Opening of a Contact

Exactly!

Back EMF is always LOWER than what is applied.

Yes, but the spike is not back EMF, it is forward EMF.
Since You have the book by Paul Scherz 2nd edition, please read it.

@ lighty, jibbguy
I agree.

about time compressed, is it another way of saying a very sudden high potential rise and fall?

That's the way I have interpreted it too.
We know the energy in the coil when it is saturated, that energy has to go some where when the applied current stops, if there is no significant current the voltage will be high, especially if time is short.

Forward EMF.

This is just like in the army: "if they don't understand; say it again, but louder"

[Hoppy]

John Bedini talks in terms of converting back EMF to forward EMF in this link:
John C. Bedini: Back EMF Motor / Generator / Battery Charger

The power coil discharge to the battery is what I think he is referring to. This will contain the radiant energy from the collapse of the power coil field. When discharged into a load, a pulse current flows for a time period and level dictated by the impedance of the load and the energy level stored in the coil. The resulting high voltage energy stored in the coil is in effect is a conversion of the supply input energy from a much lower voltage but higher current level. The 'leading edge spike' produced at the instant of the switch closing is the result of the coil inductance holding back the rise in current in the power coil.

The mystical radiant energy according to theory is 'sucked-in' during the magnetic field collapse and is additive to the forward EMF. This 'sucked-in' radiant energy is as a result of the initial compression of the aether caused by the coil charging. As I see, the forward EMF, although having a higher voltage level than the charging battery, will produce no more real power dissipation in the load than the originally applied power to the power coil, assuming we ignore any possible gain from the radiant event. It will in fact produce a lot less real power because of reactive switching losses. This is why John Bedini talks in terms of a typical 50% electrical throughput efficiency for the monopole energiser.

Hoppy

[Aaron]

@Nilrehob

Nilrehob,

Define EFM in your own words in simple terminology WITHOUT technical jargon. Explain in very simple terms conceptually what it is.

Also, separately define FORCE.

Also, separately define if FORCE in EMF is actually a force or not.

All with simple visual analogies and no technical jargon allowed.

[boguslaw]

John Bedini talks in terms of converting back EMF to forward EMF in this link:
John C. Bedini: Back EMF Motor / Generator / Battery Charger

The power coil discharge to the battery is what I think he is referring to. This will contain the radiant energy from the collapse of the power coil field. When discharged into a load, a pulse current flows for a time period and level dictated by the impedance of the load and the energy level stored in the coil. The resulting high voltage energy stored in the coil is in effect is a conversion of the supply input energy from a much lower voltage but higher current level. The 'leading edge spike' produced at the instant of the switch closing is the result of the coil inductance holding back the rise in current in the power coil.

The mystical radiant energy according to theory is 'sucked-in' during the magnetic field collapse and is additive to the forward EMF. This 'sucked-in' radiant energy is as a result of the initial compression of the aether caused by the coil charging. As I see, the forward EMF, although having a higher voltage level than the charging battery, will produce no more real power dissipation in the load than the originally applied power to the power coil, assuming we ignore any possible gain from the radiant event. It will in fact produce a lot less real power because of reactive switching losses. This is why John Bedini talks in terms of a typical 50% electrical throughput efficiency for the monopole energiser.

Hoppy

There is nothing mystical if you realize that Earth magnetic field is everywhere around.It HAS TO add to coil field or be repelled and then flood coil place again when coil field collapse.Both effects should manifest itself as tiny electrical signal.Nothing important for small systems, but this is really OU ! Consider this theory, because it's simple.

For God Sake! something must be going on related to Earth magnetic field, because such effect WAS cited in old good electronic books about vacuum tubes !

[lighty]

Earth's magnetic field at surface is about 0.2-0.7 Gauss. I'm pretty much sure it can easily be ignored, especially in the case of inductive discharge and coils with saturated cores and magnetic field that is several thousand times stronger than Earth's magnetic field.

[boguslaw]

Earth's magnetic field at surface is about 0.2-0.7 Gauss. I'm pretty much sure it can easily be ignored, especially in the case of inductive discharge and coils with saturated cores and magnetic field that is several thousand times stronger than Earth's magnetic field.

But it is FREE! Let it be weak..or not ?

You know, there is a game when two teams are pulling a rope with knot on it to move knot on one side or another.If teams are of the same power (in balance) - knot is not moved far. The same weak force and balanced forces (!) seems the same from outside.

Anyway - got a weak effect ? fine, then repeat it million times with positive feedback.Now you have power...

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[nilrehob]

Aaron

Define EFM in your own words in simple terminology WITHOUT technical jargon. Explain in very simple terms conceptually what it is.

No technical jargon? Wow, You really tie me up here! But I accept the challenge. I'll try to be as simple as possible, but please bear in mind that English is not my preferred language.

EMF, ElectroMotive Force (or just E in the metric system), is the difference in potential in a source that can make a current flow through a circuit.
You can also say that EMF is is the characteristic of any energy source capable of driving electric charge around a circuit.
A common unit is Volt and is defined as the difference in potential that can be maintained when the circuit is open.
In a battery, chemical energy is converted to EMF.
In a generator, mechanical energy is converted to EMF.

Also, separately define FORCE.

I guess F=m*a won't do although the unit actually is Newton? I'm not sure what You want here. Is it a trick question?

Also, separately define if FORCE in EMF is actually a force or not.

Its not.

All with simple visual analogies and no technical jargon allowed.

Now its Your turn, I expect You to do the same, "in your own words in simple terminology WITHOUT technical jargon"
When You've posted Your contribution, I hope we can continue to coils?

[lighty]

Anyway - got a weak effect ? fine, then repeat it million times with positive feedback.Now you have power...

The only problem is that one of the teams requires the energy input from user to even be in competition. Now, since you presumably move Earth's magnetic field for a certain amount of energy you had to give, you will get exactly the same amount of energy back. Minus losses. Which is well under COP<1.

Passive systems like Earth cells are potentially another thing.

[boguslaw]

The only problem is that one of the teams requires the energy input from user to even be in competition. Now, since you presumably move Earth's magnetic field for a certain amount of energy you had to give, you will get exactly the same amount of energy back. Minus losses. Which is well under COP<1.

Passive systems like Earth cells are potentially another thing.

Ed Leedscalnin permanent magnetic holder can store electric current indefinitely and hold quite a big iron mass. Not a powerful effect but it's confirmed.
How is this possible ?

[Aaron]

current

This is relates to how current can be maintained in a coil after input power is removed and is one way, there is another. Telsa has his own current definitions and called the impulse a current even though it isn't electron current or magnetic current.

[lighty]

Ed Leedscalnin permanent magnetic holder can store electric current indefinitely and hold quite a big iron mass. Not a powerful effect but it's confirmed.
How is this possible ?

I know it is possible since a few years ago I built a hell of a large PMH. I used precise laboratory gaussmeter to measure a flux at various points around "energized" PMH. The results were very interesting to say the least and they confirmed what Leedskalnin was describing. Even more interesting were measurements during various stages of keeper removal. So, the effect is real.

However, I still fail to see the connection with Earth magnetism. To energize PMH you have to put in quite a lot of electrical energy and while PMH will keep it, it will not produce any excess energy in terms of magnetism or electricity. Granted, it will hold keeper and some large mechanical load so in that way it is producing work as much as any permanent magnet. So, what PMH has to do with Earth's magnetic field?

[Aaron]

forward emf

No technical jargon?

Thanks for doing that Nilrehob!

I believe my explanations using the gas pressure analogies were about as non-technical as one can get.

Forward EMF as it is used throughout virtually every reference is one thing...the applied power to charge the coil to begin with and that is it. Back EFM opposes the forward emf.

When disconnecting the coil, you get the spike - and regardless of any current existing at this point, it isn't considered forward or back emf.

Please tell me if the spike is Forward EMF, then where is the Back EMF opposing the spike?

[sucahyo]

The power coil discharge to the battery is what I think he is referring to. This will contain the radiant energy from the collapse of the power coil field. When discharged into a load, a pulse current flows for a time period and level dictated by the impedance of the load and the energy level stored in the coil. The resulting high voltage energy stored in the coil is in effect is a conversion of the supply input energy from a much lower voltage but higher current level. The 'leading edge spike' produced at the instant of the switch closing is the result of the coil inductance holding back the rise in current in the power coil.

At first I thought that mentioning spike happen at switch closing is a typo, but after I read coil inductance holding back it is different. Isn't inductive collapse happen on switch opening, when current is disrupted?

Lighty mention the difference in radiant thread, but for lighting up 3 Volt LED with 1.5V powered coil induction, you can achieve it by disrupting either positive side or negative side.

This test should be easily replicated if you have 1.5 volt battery, a coil and a LED. Connect LED to coil in parallel. Connect both with reverse polarity of the LED, don't connect the LED pos to battery pos, but connect the LED neg to battery pos and LED pos to battery neg. LED won't light up otherwise, since spike direction is in reverse of powering current.

Notice that LED wouldn't light up when you connect the power, or after. LED will flash once you disconnect the power.

The BEMF I mention in this video is actually inductive collapse spike ........
YouTube - BEMF from 1.5V battery light up CFL bulb
YouTube - How BEMF happen #1, LED version

[nilrehob]

Please tell me if the spike is Forward EMF, then where is the Back EMF opposing the spike?

The collapsing field generates the fwd EMF spike.
Do You say that when the field is gone and you have the spike, the spike should generate a field?
The field in a coil is generated by current, not by voltage, and as the spike has very little current then maybe its too little to generate a field again. Maybe it does, but its hard to detect as it is so small?

I took the liberty to simulate a small circuit in a free program called Qucs that runs on Linux, I think it runs on Windows too.

The switch S1 is turned off after 10 ms. The probe Pr1 measuring volt is shown in the graph.
Note that the battery V1 is only 1 Volt, and the fwd EMF spike measured by Pr1 is reaching 200 Volt.
Even a simulation program knows about fwd EMF and that it sure can be higher than the source, in this case the battery.