Inductive Kickback

[ramset]

Synchro
sometimes we post when we shouldn't...a bit too much to drink is one of those times.
maybe you should take a break ...

Chet

[synchro1]

@Tinman,

That's how to measure "Flyback" recovery; First we back the Reed switch away from the "Sweet Spot"!

LoL: Look how little "Flyback" we recover when we only charge the power coil part way!

[citfta]

I have asked Stefan to lock this thread as it no longer serves a useful purpose.  I have also asked that synchro be put on notice for his childish behavior.

[tinman]

@Tinman,

That's how to measure "Flyback" recovery; First we back the Reed switch away from the "Sweet Spot"!

LoL: Look how little "Flyback" we recover when we only charge the power coil part way!

Why lock the thread?-because of synchro?

Anyway,below is a scope shot for the test you requested.
Notice the ringing starts when all the current has been dissipated from the inductor.

[gyulasun]

Hi all

Youp seems not to be so easy this flyback spike understanding.

For me what i see on the scope is that at the end of the pulse, when the reed sharply opens, the current trace goes to almost  instantly (verticaly) to zero. And only AFTER this shut down,  begins the flybackspike.

So to me the current who build up the magneticfield is gone , totally dissipated, finished at the end of the pulse. He was totally used to precisely build the magnetic field. So he has no more direction at all.

Than it stays the expanded magnetic field around the coil (??) and what exactly happens at that point is ?? But  on the scope ,  suddenly a strong narrow  "high negative voltage" trace appears  and also a strong very very narrow and strong current trace (not shown on the pic) also. What does create this event is still puzzling to me.

If it is the collapsing of the magneticfield please explain the process with simple words if possible.
But anyway to me that is a new current who has nothing to do directly with the one that created the magneticfield. It is what i call hes "son"

Youp, please don't shoot me down it's only an idea.

Laurent

Hi Laurent,

Would like to ask which circuit point did you measure the current you show at the yellow trace? 
It is the input current going into the drive coil, is this correct? 

Here is the schematic, please describe where you inserted the current sensing resistor,  was it in series with the drive (5mH) coil? in this case use number 5 as a reference to that point:
http://overunity.com/16167/sharing-ideas-on-how-to-make-a-more-efficent-motor-using-flyback-moderated/msg466151/#msg466151 

Thanks, 
Gyula