Hi!
I did a couple of little experiments today with an inductor core, and have managed to tie my brain in a knot. Can anyone help me explain the difference between these two scenarios to myself?
Experiment 1.
I took two lengths of 0.5 mm enamelled wire, held them together and wrapped them together a few times clockwise around a bobbin, so that there were 14 turns of each, forming two layers. I added the core and measured each winding at about 1.34 mH at 1KHz. Then I put the pair in parallel, and measured 1.35 mH. The two coils of wire are acting as a single, thicker coil, which is pretty much as I expected. (I could also get a very low reading by putting them in anti-parallel.
Experiment 2.
I wound a layer of 15 turns of wire around the bobbin, clockwise, and then wound a second layer anticlockwise. The windings read about 1.5 mH each. When I put them in parallel, phase aligned, I read 0.75mH - half the value of a single winding. (Or about zero when anti-parallel.) The two coils are now acting independently, as though they are two separate inductors.
So, both are two windings, in parallel, on the same core, wired so that the signals are in phase. But they behave differently.
Is the second scenario different simply that the two coils can no longer act as a single entity, because one is anticlockwise?
Thanks!
Stewart
I did a couple of little experiments today with an inductor core, and have managed to tie my brain in a knot. Can anyone help me explain the difference between these two scenarios to myself?
Experiment 1.
I took two lengths of 0.5 mm enamelled wire, held them together and wrapped them together a few times clockwise around a bobbin, so that there were 14 turns of each, forming two layers. I added the core and measured each winding at about 1.34 mH at 1KHz. Then I put the pair in parallel, and measured 1.35 mH. The two coils of wire are acting as a single, thicker coil, which is pretty much as I expected. (I could also get a very low reading by putting them in anti-parallel.
Experiment 2.
I wound a layer of 15 turns of wire around the bobbin, clockwise, and then wound a second layer anticlockwise. The windings read about 1.5 mH each. When I put them in parallel, phase aligned, I read 0.75mH - half the value of a single winding. (Or about zero when anti-parallel.) The two coils are now acting independently, as though they are two separate inductors.
So, both are two windings, in parallel, on the same core, wired so that the signals are in phase. But they behave differently.
Is the second scenario different simply that the two coils can no longer act as a single entity, because one is anticlockwise?
Thanks!
Stewart