STEORN DEMO LIVE & STREAM in Dublin, December 15th, 10 AM

[teslaalset]

@teslaalset.
I think @Omega_0's explanation of the seeming phase shift is the correct one, that it, there is no phase shift between I and V.

I guess I am too focussed on my own insights. That is always dangerous 
I'll step back and try to understand Omega's approach.

Now, if I understand Omega_O correctly following is happening:
- pulse is generated just before the magnet enters the coil position. The L value is around 0.98 Henry. This causes the current to stay low in value
- then the magnet passes the coil and saturation is occuring leading to low L value and high rise of current.

Well, if the pulse voltage is 12 V and the coil value is say roughly 1 Henry the current change can be derived from the following formula : 
U_L= L x di/dt.
From that one can calculate the current acceleration value after switching the power.
So, in this case, di/dt = 12 A/s

[PaulLowrance]

Just to the point. The core inductance is on the order of micro henries. Just forget about the 0.98 henry measurements.

[teslaalset]

Just to the point. The core inductance is on the order of micro henries. Just forget about the 0.98 henry measurements.

Paul are you saying that the values shown in Steorn's video are fake?
Have a look at about 25 second from the start of this video:
http://www.youtube.com/watch?v=EMOTqzjm8eM

[PaulLowrance]

It's not fake. It's not of any use except Sean was trying to show a point how the inductance changes a bit. That's all. To be honest with you, that Steorn inductance measurement is 100% worthless in terms of replicating an Orbo. That LCR meter will not saturate that core.

To be more specific to my previous post, when the magnet is at TDC, the core has ultra high permeability (that lasts a few microseconds in my replication). When core is in that state of ultra high permeability, changes in current have no measurable effect on magnet interaction. What decreases the attraction between magnet & core by measurable amounts is when the core is well into the saturation curve.

A few people have said how the core is always in saturation. As the magnet approaches the core, it has no problem reorienting the domains to align with the field from the magnet. In order for the coil to change that orientation back to a loop requires high current. So on a scope shot one will initially see a short period where the current hardly changes, micro amps, and then suddenly the current will soar upward. In my setup, that short period is a few micro seconds. Then the core (relative to the coil) switches almost instantly from ~ a henry to ~~ a hundred micro henries. When coil inductance is low, micro henries, that's when work is done; i.e., when the core & magnet attraction begins to decrease.

Since the inductance is so low during the pulse, it may seem like there's no EMF, but there is a bit. You can see in some of Steorn's scope shots the RL rise time, microseconds, not milliseconds. So it does take work, albeit small, and there is excess energy.

[teslaalset]

.....
A few people have said how the core is always in saturation. As the magnet approaches the core, it has no problem reorienting the domains to align with the field from the magnet. In order for the coil to change that orientation back to a loop requires high current. So on a scope shot one will initially see a short period where the current hardly changes, micro amps, and then suddenly the current will soar upward. In my setup, that short period is a few micro seconds. Then the core (relative to the coil) switches almost instantly from ~ a henry to ~~ a hundred micro henries. When coil inductance is low, micro henries, that's when work is done; i.e., when the core & magnet attraction begins to decrease.

Thanks Paul, that is very useful data.
I had very similar sequence in mind, but with a factor 100 on the inductance off. Good to know.

b.t.w. how did you obtain your MetGlas cores a while ago?
I tried to get samples from www.metglas.com, but no response at all.
Then I tried Elna. They have a lead time of almost half a year. Terrible!