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labview1958

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Everything posted by labview1958

  1. Is the magnetic field on the pole surface uniform? Or it has ONE peak pole? Or it has more then one peak per surface? Where can I can get info or formulas regarding the value of the magnetic field exactly on it's pole surface?
  2. Let me clarify. I am actually getting a sine wave which shows that the force is always repelling. I do not have attractive force, just more repelling or less repelling force. Put it another way: a "DC" sine wave. My guess is that the discs were magnetized perpendicularly. Only I could not get them aligned as the point with the strongest field is not the centre of the disc. for example the earth's geographical north pole is not where the magnetic north pole is.
  3. Are you implying that half the bottom of the disk is a north pole and the other half a south pole? I have never come across such a magnet. It is a normal disk magnetwhich is available for sale on the net.
  4. Well the bottom of the magnet is a north pole and the top is a south pole. Well the magnet must be oriented vertically.
  5. The magnets are oriented in the vertcal direction. Thus north poles face each other. I also rotated a small disk magnet above another much larger (about twice the diameter) disk magnet. I got the same result.
  6. It is an extremly smooth sine curve with one peak and one valley for a 360 degree turn.
  7. I have slowly rotated a disk magnet above an identical disk magnet. The result: a sine wave. A graph of one peak and one vally per 360 degree rotation. The north poles are facing each other and are perfectly alligned. I am measuring repulsive force.Why is that? can anyone help?
  8. Is it true that if a magnet is rated 1 Tesla, it should be considered as 1/3 Tesla for the attractive force between a steel plate placed on top and touching the magnet. Is it because there is always a small gap between the touching steel plate and magnet?
  9. Let's say the magnet is a cube of 1mm. Then the area of the north pole is 1mm x 1mm = 1 x10^-6.m^2. Is the total current on the north pole 8x10^5 x 1 x 10^-6 = 0.8 A ?
  10. A permanent magnet can be model as a solenoid. If I have a permanent magnet of 1 Tesla, how much current is that equivalent to? My guess is about 1x10^5 Amps. Is that right?
  11. If I have a cuboid shape magnet (1mx1mx1m) with a field rated at 1 Tesla, can I find it's magnetic dipole moment (A m^2).
  12. The magnets are rated at 1.23 Tesla. Should I use 1.23 Tesla or use this formula: B = mu(H+M) where H is 1.23T and M=0? Thus B=muH where H=1.23T, thus a much weaker B in my formula?
  13. The formula for the maximum force between identical magnets is: F = AB^2/2mu where A = cross-section area of the magnet in m^2. I have taken out two identical magnets from the manufacturer pack rated at 1.23 Tesla. I have found the Force by calculation to be 100N or can lift 10 kg. However the manufacturer pack says that one magnet can lift 4 kg. Is there a flaw in the formula or calculation?
  14. anyone intersted in discussing superconductivity?
  15. I have designed a setup for measuring pinning force of a superconductor. Here it is. Can it work? The superconductor is in the superconducting phase and it is rotated very slowly. Would the Balance show a net attractive force?
  16. Is there a formula connecting the levitational (lorentz) force of a bulk superconductor with it's pinning force? Does the pinning force increases with the lorentz force? Where can I find the answer?
  17. Sorry to but in. Since this message is about superconductivity then ...... Is there a formula connecting the levitational (lorentz) force of a bulk superconductor with it's pinning force? Does the pinning force increases with the lorentz force? Where can I find the answer?
  18. Is the moving filament over a conducting sheet track-steady theory (moon page 339) the same as the A-φ method ?
  19. Which type II superconductor has the strongest pinning force? Where can I find the ANSWER?
  20. When an ordinary train passes on a track, the track becomes hot. When a maglav train passes on a track, does the track becomes hot? Which is hotter, the maglav track or the ordinary train track? Is there a way to calculate the heat?
  21. Is it true that if the copper sphere is at 77K and room temperature is 300K, it would rapidly rise in temperature by let's say 50K compared to the copper sphere being at 250K rising to 300K. In other words the rate of heat transfer depends on the difference big or small between the two temperatures?
  22. The magnet is inside the hollow sphere.
  23. Can someone make this simpler? The magnetic field on the z axis of a solenoid (in Gaussian units) is: B=[2\pi(N/L)I/c][sin A_2-sin A_1], where A_i is the angle between a line perpendicular to the axis of the solenoid at one end and a point on the z axis.
  24. I have a similar problem. If I have a 100 gram copper sphere immersed in liquid nitrogen for an hour it would have a temperature of 77K. If I take it out an put it in "still" air at 300K, how long would it take it to come to 300K? Can that be calculated for "still" air?
  25. A correction Drag Force=k*Lift Force where k = ω/v and ω = 2/(μσΔ) • where μ = permeability of free space • v = velocity of conductor/magnet • σ = conductivity of track • Δ = thickness of conductor ω = characteristic velocity Where to get additional experimental data?
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