I ran this test, and here are the results I got.
The phase flipped when I turned the coil as expected. But I'm not sure how to interpret these results. My theory is that this is caused by the alignment of the magnetic domains within the iron. As one domain is effected by the magnetic field...
Could you explain why inductive coupling and eddy currents would give rise to this phase change? Not the -90 degree phase change, but the change in phase change with position.
You are right, the phase difference when the two coils are concentric is 270 degrees and as I move the sense coil away from the drive coil the phase difference increases. At a 6 inch separation I get a phase difference reading of 274.74 degrees.
Sure, I have one 8" solenoid with 300 turns being driven by an audio amplifier at 10Hz sine wave. I also have a "sense" coil which is 2" in diameter with 20k turns. These are laying flat on a half inch thick piece of low-carbon iron.
The sense coil signal goes into a voltage follower to...
Hey all,
I'm working on a project now where I am using a solenoid driven at a 10Hz AC current to create a magnetic field on a solid piece of low carbon iron, and then using a smaller solenoid to capture the magnetic flux coming from the iron.
By measuring the phase of the resulting waves...