Back EMF vs Collapsed Spikes.....

[tao]

Back EMF vs Collapsed Spikes.....

http://www.youtube.com/watch?v=9_rvJQb2SDY

Watch the above and learn the KEY difference...

More info at a later time......

[BEP]

Yes. This is completely correct. However, rather than argue the point most will use the terms being used.

I know the difference between CEMF and Flyback. The big difference is you need to avoid or prevent BEMF/CEMF and try to make use of Flyback. (If using SS then most will simply short it out rather than use it and they usually don't consider real CEMF except as reluctance.)

BEMF is reactive force fighting the work force. Flyback is wasted energy (for narrow minded folks).
Newton's third law: "For every action, there is an equal and opposite reaction." OR properly translated: "For every force, there is an equal and opposite force." (I understand he did not write his papers in a modern speak)

To fight BEMF your coil must be an open circuit.

To make use of Flyback you can add a second 'open' coil within your first coil with a single end connected to the first. The key is to counterwind that second internal coil. The term used was 'induced stepping'.

You've heard of capacitive Jacob's ladders? Now you know how to make an inductive form.

[gyulasun]

@Tao

Thanks for this topic and the video link, looking forward to read more on this very interesting and important topic.

@Bep

May I refer to your circuit uploaded here because it perfectly fits to this topic: http://www.overunity.com/index.php/topic,2831.msg41943.html#msg41943

which if I understand well make use of the energy of the collapsed spike when the cathode follower switches off. It means then you can roughly half the switch-on time for the cathode follower because the "other half"  of energy can come from the capacitor which stores the energy of the spike at collapse,  right?  Please comment if I am wrong.
I would be interested in a schematics also on your thoughts in your last post, though I guess now it is mainly included in the one at the above link? 

Thanks,

Gyula

[wattsup]

Are you guys absolutely sure about this. I always thought BEMF was the current inrush that happens when you collapse a field. Why was this not put forth a year ago?

Many members on the board (including me) have been taking about BEMF and most have got it wrong. Ouch and a half.  @Hum - no comment please.

Tao, this one bit of info has opened my eyes. Thanks. Finally someone who can vulgarize the subject.

So in layman terms BEMF is the circuits natural ability to counter current flow when the circuit is running or on. Sort of like a natural rheostat.

So when you open one end of the circuit, the polarity reverses and current goes back to the source.

So what happens if you open the other end instead. Does it still go back to the other source?

If yes, does this mean both + and - could act as source? This question has been bugging me for a long time now.

So what happens if you open both ends of the circuit at the same time?

Maybe opening both ends at the same time will create what Tesla did with sending spikes or sparks perpendicular to the coil.

@BEP

That circuit referred to by gyulasun reminds me of your reverse wound Cook Coil. Is that a diode on the circuit? Or a zener diode?

By the way, I'll be winding my primary this weekend on my CBC Build 2, but now I think I will do it in a way to be able to slide it off and reverse the direction to do trials in both directions.

[gyulasun]

That circuit referred to by gyulasun reminds me of your reverse wound Cook Coil. Is that a diode on the circuit? Or a zener diode?

Hi,  if I may chime in... it is a drawing symbol for a Schottky diode. Schottky diodes are inherently capable of switching at a very high speed which is needed here because when you switch off current in the coil the collapsing field induces the spike "at once" and you do not want to miss any small part of it by using a low speed diode like 1N4007 for instance.

Gyula