- #1
mik652
- 3
- 0
Hi,
can someone explain me the next experiment:
If I have an AC coil on iron stick, and if I put Cu ring on that stick concentric with AC coil, when I turn coil power supply, the ring will levitate on some height. My question is:
Powered AC coil produces an AC magnetic field. If I put a closed conducting loop (Cu ring) in that magnet field, in the ring will be induced current (Faradey law) in such direction to opposes magnetic field from AC coil (Lenz law). But in first quarter (N pole increasing) of sine wave of magnetic field from coil, the ring and and the coil will reject each other. In second and third quarter of a sine wave (N pole decreasing, and S pole increasing), the ring and the coil will attract each other. And in forth quarter of sine wave (S pole decreasing) the ring and the coil will reject each other again. Base on this I can conclude that the ring should stay in one position and should oscillate. Where is my mistake?
Maybe this is the answer (in first quarter, the ring is close to coil, and the reject force move coil on some distance. When force change its direction, inertia of the ring move the ring for a while and then starts to oscillate?
On the other hand if I draw the lines of forces that acts on ring, the are in such direction to tray to increase and decrease (depend from quarter of sine wave) the radius of the ring. The forces lines lie in ring surface.
Base on this if I put the same coil in the same magnetic field as described above, but in other position, so the magnetic field lines and the ring surface line are at 30 degrees, for example. Ring is fixed in its center, so it can only rotate, what will happen with ring. Will it rotates to position that surface line and magnetic field lines are at right angle, or to position where the angle between the lines are at 0 or 180 degrees? If we draw the lines of forces we can find that the ring will just oscillate in any position.
Where is my mistake in understanding of this situation?
Best regards
can someone explain me the next experiment:
If I have an AC coil on iron stick, and if I put Cu ring on that stick concentric with AC coil, when I turn coil power supply, the ring will levitate on some height. My question is:
Powered AC coil produces an AC magnetic field. If I put a closed conducting loop (Cu ring) in that magnet field, in the ring will be induced current (Faradey law) in such direction to opposes magnetic field from AC coil (Lenz law). But in first quarter (N pole increasing) of sine wave of magnetic field from coil, the ring and and the coil will reject each other. In second and third quarter of a sine wave (N pole decreasing, and S pole increasing), the ring and the coil will attract each other. And in forth quarter of sine wave (S pole decreasing) the ring and the coil will reject each other again. Base on this I can conclude that the ring should stay in one position and should oscillate. Where is my mistake?
Maybe this is the answer (in first quarter, the ring is close to coil, and the reject force move coil on some distance. When force change its direction, inertia of the ring move the ring for a while and then starts to oscillate?
On the other hand if I draw the lines of forces that acts on ring, the are in such direction to tray to increase and decrease (depend from quarter of sine wave) the radius of the ring. The forces lines lie in ring surface.
Base on this if I put the same coil in the same magnetic field as described above, but in other position, so the magnetic field lines and the ring surface line are at 30 degrees, for example. Ring is fixed in its center, so it can only rotate, what will happen with ring. Will it rotates to position that surface line and magnetic field lines are at right angle, or to position where the angle between the lines are at 0 or 180 degrees? If we draw the lines of forces we can find that the ring will just oscillate in any position.
Where is my mistake in understanding of this situation?
Best regards