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

[Omnibus]

@Omega_0,

I've tried that already (simple calorimetry). I've made a device and have written a program for my students to study heat of reaction, heat of solution etc. and I tried to use it for this purpose, to no avail. The heat released is too small for the device to detect it. Wonder if you're talking about the older results I reported which I corrected later. Now, corrected, for the kHz frequencies the maximum OU effect I got is around 1.9.

@broli,

The y-axis shows times, not percent. It would be an amazing OU effect if it turns out to be real.

[Omnibus]

There is no way to isolate the capacitance from the coil, but there is a way to check its effect by adding a small but known capacitor in parallel. If the OU is unaffected, then it is purely due to other reasons.

On the other hand, if you see a big increase in OU after adding the cap, then we can suspect the coil parasitic capacitance to be a culprit. I guess you have done that, but its worth repeating with a current probe.

@Omega_0,

Just checked it with a 0.0047uF in parallel. With capacitor the OU is 1.989. Without capacitor the OU is 1.997. Thanks for that suggestion. I think that's the crucial experiment to prove capacitance isn't an issue. Now I'll go on with the unwinding and will get back with results as soon as possible.

REDACTED: I have to correct the above because I had put the capacitance after the current probe. When I place the capacitance correctly so the current probe measures both the current through the coil and through the capacitor there is a clear increase in what appears as OU. This is to be expected, though, and I don't think it proves the OU is due to the parasitic capacitances in the coil until they themselves are measured. A telltale sign is that when rewinding the same primary coil wire on a separate spool (even with the primary wound underneath it) no OU is observed--the underunity is severe. Only when the transformer coil is used as is, even without the metal core, only then there is OU.

[broli]

While you're at it let me propose some very boring experiments  . Since you're going to wind it around a pvc tube this gives you the perfect opportunity to try out different cores, from transformer to iron and perhaps even a copper tube, at different insertion distance and compare results. It's tedious because it's a lot of repetitive work.

[Omnibus]

@broli,

The core didn't appear to make one bit of a difference. I got the same effect without the core. But now, get this, when I wound half of it on a different plastic and tried it it showed severe underunity. Now, first, let me mention that the secondary coil has about 70 turns while the one I just tried, wound around a different spool, yielded 470 turns. I'm winding now the second half of it and we'll see what happens (second part has 360 turns, so all in all we have about 830 turns in the primary).

Mind you this, the coil, intact but without the core, is made up of layers--primary coil being on top of the secondary. The secondary is made up of a much thicker wire. The primary coil, like I said, is made up of consecutive layers of the first part (green) and the reddish second part of the wire (the input of the transformer has a middle point). Probably the secondary coil is acting as a core and that brings about the effect. Let me do the second half and then we'll know better (also, will have to take apart another transformer to have the air core at hand).

[Omnibus]

OK, here's what I'm finding thus far. When I try the first part of the primary coil and wind it on a brand new spool I'm getting severe underunity. Severe underunity is observed when I add the second part of the primary coil to the first part. Now, having seen that I decided that somehow the presence of the secondary coil would make a difference. So I first wound that thicker wire, constituting the secondary coil, on the original spool, then isolated it with its original tape (had to pull it out of the trash) and then wound the second part of the primary coil around it. Severe underunity again. Now, what's going on? Wasn't there supposed to be capacitance and so on and so forth that would appear as OU? Obviously, the original air coil (which as I said shows OU even without the metal core) is wound in some special way which I couldn't discern entirely because wires are so tiny. Like I said, the first and the second part of the coil are wound in consecutive layers somehow. At one point I thought they were bifilar. That doesn't square with the fact that I'm observing current lagging behind voltage, typical for a regular air coil with inductance. So, there's something interesting here which is at play and is still escaping me. I'm tending more and more towards concluding that this is a real OU (my confidence being shaken earlier by the capacitance argument).