Back EMF vs. Collapsing Magnetic Field Spike

[darkwizard]

Put a 85 v neon light and a 4.7k 1watt resistance between the collector of the transistor and the emitter this will prevent any damage to the transistor.

[nilrehob]

@ Jetijs

Nice motors!

My scope is a dual-channel, so I just did a test with one over the coil to get the voltage and one over a resistor in series to get the amp. The voltage is a square-wave while the amp is a sawtooth-wave.

But no spike as on Your and everybody else's shots

I'll take a timeout from this thread now and build the SS SSG in between my Tesla switch tests.
If I don't get the mysterious spike with it I guess I'll have to stop being a skeptic enthusiast and become a regular enthusiast, it might help

@ darkwizard

I will, thanks.
The first time I encountered the SSG was on one of Sephiroth's very good vids on you-tube;
"don't forget the neon!" he said, and I won't

[nilrehob]

I just did a quick build of the SS SSG, I was too curious to make a proper build.
Its working like a charm although it looks like a crows nest with all wires everywhere.
The battery being charged is climbing fast and if I replace it with the small cap I've been using it shoots like a rocket.
Thank You neon!

But the scope looks just like before. No extra spike anywhere.
You guys must be kidding me!

I'll see if I can tune it with other resistors or whatever tomorrow.
Good night!

[darkwizard]

I`t is suppossed to give you another spike? NO

[Aaron]

charging batt takes spike

The battery being charged is climbing fast and if I replace it with the small cap I've been using it shoots like a rocket.
Thank You neon!

But the scope looks just like before. No extra spike anywhere.
You guys must be kidding me!

The battery or capacitor being charged is soaking up the spike.

[Jetijs]

But the scope looks just like before. No extra spike anywhere.
You guys must be kidding me!

You must disconnect the battery to see the spikes, because if a battery or cap is attached, it absorbs the spike. You can do this for a short time, but there will be a risk to damage the transistor. Also a neon across the transistor will not show the real spike, because neon will start to conduct at 90v. To see the spike in full magnitude, you must remove the neon and disconnect the charging battery or cap. But do that quick or else the transistor will fry.

[ren]

Jet is right Heed what he has to say!


I upgraded my trifilar to a quadfilar and upon testing it for transients I popped all three MJL's almost instantly. Funny, I could run it on two power windings quite comfortably without a load connected. As soon as I moved to three it just packs it in if there is no load.

Also worth noting that you should be able to see the start of the spike even with the battery connected. Mine got larger (with load connected) when I went up to three power wires.

[nilrehob]

@ Aaron, Jetijs and ren

First I thought: "Yeah, thats it! The cap/bat is absorbing the spike, thats why It doesn't show up on the scope." and went to test it on my SSG-fan. Sure, there was the spike once I had disconnected the neon and cap/bat, and two echoes each about a tenth in size of the one before.

But then the skeptic in me came back: "Of course it's an even higher spike now, it's the same as before, just compressed in time a bit more which makes it higher!"



How do You get both the by-classic-science-unknown-radiant-spike and the good-old-measurable-and-calculable-spike on the scope at the same time?

[Matthew Jones]

The the energy that shows up in spikes from a radient discharge travels at high speeds. They are of such high frequency and that you can only see them on a scope when they are going to a load (IE Voltage burning in the neon). They slow down enough that the scope can draw them.
When you add a charge battery to your system the actual radiant part of the spike has a bigger pipe to travel and the scope can no longer see it at its full voltage.
You should with a charge battery hooked be able to see the base of the spike. This is the point at which the PURE voltage spike starts to convert to a heavier mass and create and mix with the input current.
The spike will go from 300-500volt down to 30 +- volt.
This why on scope when looking at the spikes in the full veiw, they will expand at the base. But the tops do not stretch as you focus the scope in on them.

Matt

[darkwizard]

Nilrehob i understand what you are saying, there isn't any extra spike here, the energy that you input to the coil is converted in high voltage.

There is what Tesla discovered, Tesla discovered that the auto induced emf spike is higher in potential than EMF and it called radiant, nothing else.

Any person with a background of electronics knows what is this spike but they ignore it, they simply call this spike BACK EMF

[nilrehob]

Then why make it so mystical?
Is this the best way to handle the "free energy" critics?

[Aaron]

The spike is NOT back emf

Back EMF "voltage" is lower than the input voltage 100% of the time. Back EMF is NOT the spike, period - it has been spelled out clearly that Back EMF is NOT the spike.

I would appreciate no more comments about calling the spike Back EMF because it is NOT WHAT THE SPIKE IS. It is misinformation plain and simple and everyone using the term back emf for the spike is simply doing so incorrectly - out of not even knowing what the difference is.

LOOK AT THE CHRONOLOGY OF EVENTS - it is common sense:

1. You charge a coil.
2. DURING the applied charge on the coil, LENZ's Law is in effect and you get BACK EMF - DURING THE APPLIED CHARGE.
3. You disconnect the power and you get the spike.

It is no more complicated than that...you get the spike AFTER the applied power and AFTER the Back EMF have DISAPPEARED.

[darkwizard]

Flyback diode - Wikipedia, the free encyclopedia

Induction at the Opening of a Contact

According to Lenz's law, if the current through an inductance changes, this inductance induces a voltage so the current will go on flowing as long there is energy in the magnetic field. If the current can only flow through the air, the voltage is therefore so high that the air conducts. That is why in mechanically-switched circuits, the near-instantaneous dissipation which occurs without a flyback diode is often observed as an arc across the opening mechanical contacts. Energy is dissipated in this arc primarily as intense heat which causes undesireable premature erosion of the contacts. Some energy is also lost from the system as a whole and from the arc as a broad spectrum of electromagnetic radiation, in the form of radiowaves and light. These radiowaves can cause undesirable clicks and pops on nearby radio receivers.

[Aaron]

What is Back EMF

This is an old scope shot from my 2000 turn trifilar Bedini oscillator.



The little stubs at the bottom are about 13 volts input....BACK EMF is occurring DURING the input portion of those little stubs. Again - the BACK EMF is occurring during those little stubs at the bottom WHILE 13 volts is being applied to the coil. Lenz Law is taking place DURING the application of 13 volts - that is where the Back EMF is.

See the tall spikes? That is hundreds of volts potential and it is those spikes that you want and those spikes have NOTHING to do with Back EMF and is NOT Forward EMF.

The most efficient coil arrangement to get the transfer of this if using a secondary is a 1:1 turn ratio. It is not a turns ratio setup for stepping up voltage, it is a time rate of change setup.

Anyone needing further clarification on what Back EMF is, please read this:

Definitions of Back EMF

• The counter-electromotive force (abbreviated counter emf, or CEMF ) Graf, "counterelectromotive force", Dictionary of Electronics is the voltage ...
  en.wikipedia.org/wiki/Back_EMF
• A voltage produced that tends to oppose the voltage that created it.
  www.dup-training.com/usmotor/moodle/mod/glossary/view.php
• Voltage induced in a circuit which opposes the applied voltage, eg in the armature of a dc motor as it rotates in its magnetic field.
  www.quarrying.org/dictionary/b.html
• The emf that opposes the normal flow of current in a circuit.
  www.hvacmechanic.com/glossary/glossary_b.htm

What is the common theme here? A counter current that opposes the applied field. The applied field, the normal flow of current, the applied voltage - these are all things that Back EMF are opposing....and it is all of these things that are NOT the spike. The spike is NOT the applied field, it is NOT the normal flow of current, it is NOT the applied Voltage and it is most definitely NOT the counter current that opposes these things that are also not what the spike are.

What law describes this action?
Lenz's Law

In 1834, Russian physicist Heinrich Lenz discovered the directional relationships between induced magnetic fields, voltage, and current when a conductor is passed within the lines of force of a magnetic field. Lenz's law states:


"An induced electromotive force generates a current that induces a counter magnetic field that opposes the magnetic field generating the current."


The FACT that the spike is not back emf has been firmly established in all basic electromagnetics for many, many, many years. It is also not a forward EMF.


Current can be maintained in a coil after power is disconnected but any of the above is not it.

[Aaron]

not back emf

Flyback diode - Wikipedia, the free encyclopedia

Induction at the Opening of a Contact

According to Lenz's law, if the current through an inductance changes, this inductance induces a voltage so the current will go on flowing as long there is energy in the magnetic field. If the current can only flow through the air, the voltage is therefore so high that the air conducts. That is why in mechanically-switched circuits, the near-instantaneous dissipation which occurs without a flyback diode is often observed as an arc across the opening mechanical contacts. Energy is dissipated in this arc primarily as intense heat which causes undesireable premature erosion of the contacts. Some energy is also lost from the system as a whole and from the arc as a broad spectrum of electromagnetic radiation, in the form of radiowaves and light. These radiowaves can cause undesirable clicks and pops on nearby radio receivers.

Yes and none of that is what Back EMF is. AND Back EMF is always LOWER than what is applied. Lower, therefore, it is NOT the spike, which can be many times higher. Back EMF is also defined as being the opposing current DURING the application of power and NOT when disconnecting the power.