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Controlled levitation of a ceramic magnet or a neodymium magnet (axes vertical) |
| No, this is not the curvature of the earth. This geometry contrary to the precedent, permits the object in levitation to rotate freely 360° around its vertical axis. If the object is made rotating, it will keep its momentum a very long time... Ceramic magnet Ø19 mm x 10 mm th. or neodymium Ø25 mm x 5 mm th.. (fly over the picture) |
Ceramic magnet (grade 5) Sizes: Ø 19 mm - th.10 mm weight:13 g |
Spherical composed objects in levitation: (Ø 65 mm or 82 mm - weight: > 50 g), the poles plane of levitated magnet have the tendency to stay parallel to the poles plane of sustentation magnets and this property is reinforced by the control of the position for witch the stability is amazing. The coupling with the coils fields becomes rapidly insufficient for a levitation elevation above 20 mm, on this test jig the practical limit of levitation is about 25 mm. A toy normaly suspended: (fly over the picture) |
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Video: 80 Ko - 10 s duration (.AVI - wmv9). (click on the picture) 
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| Note: In the geometry #5, the elements are positioned very differently compared to the precedent geometries, the elevation and trim of the levitating object are self-stability by principle, the active stabilization is applied only to the vertical axis. (4 or 6 field coils, 2 or 3 servo boards and 6 magnets sets for sustentation) | Note: A weak oscillation around the vertical axis remains during the video, showing the freedom of an object in levitation, this oscillation is the indication that a direction has been slightly privileged by the adjusments. | Note: In this demo, 6 coils fields, 3 servo controller boards and 6x2 sustentation magnets are used. One coil for elevation control is inserted at the centre for the weight compensation of different objects (not connected here). |
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Other object composed and levitation of a neodymium magnet with its axis horizontal |
| Dodecahedron on base in horizontal position. weight: 50 grams, material: aluminium, magnet: neodymium Ø25 mm x 5 mm th .test jig for geometry #5 in vertical position like used in demos at the right hand. (fly over the picture) |
Neodymium magnet Ø25 mm x 5 mm its magnetization axis is now horizontal. The magnet is separated from the test jig by an aluminium sheet. (fly over the picture) |
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| Notes : (What is difficult here: the dodecahedron...) The pentagons edges size: 26 mm. Levitation elevation: app. 16 mm (maximum safe value with this test jig: 20 mm). Video 86 ko - .AVI wmv9 - (the setting in rotation is voluntary). |
Notes : The magnets control the trim, the field coils become the sustentation coils, the optional altitude coil inserted in the center becomes the horizontal axis stability coil (in substitution of the gravity force). |
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the magnet in levitation become free along the long axis of the new domain |
| Test jig for geometry #5-6 |
Vidéo : 400 Ko, 10 s duration (.AVI - wmv9). (click on the picture) |
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| Notes : Inexpensive and compact configuration, 5 field coils, 10 Hall sensors and one servo board. This setup permits to make levitate the magnet easily at an elevation of 25 mm. This test jig can be also configured with 10 field coils (5 coils on each sides). In both cases, the coils are oriented at right angle to the longitudinal axis. this setup is nearest of the geometry #5. the properties are slightly differents. more infos in Tech's page | Notes : The adjustment of passive stopping fields at each extremity permits to curve the trajectory by the creating an "hight point" at the center of the stability axis, thus we can get the motion like the one shows on the video. The using of a laser beam for to guide the magnet along is displacement axis is very effective. more infos in Tech's page |
What does it occur if one removes the passive stopping magnets and closes on itself the “oblong” domain of the geometry #5-6 ? |
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We get a circular domaine allowing the positioning of the magnet in levitation at any location |
| Test jig for geometries #5 & #6 |
Test jig for geo #6 used in mode geo #5. |
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| Notes: 3 configurations tested : a - static positioning setup 12 field coils, 24 Hall sensors & 3 servo controller board (1 master et 2 slaves). b - dynamic positioning setup) 12 field coils, 2 Hall sensors, 4 servo controller boards and 1 small geared servo motor (for tracking the levitated magnet). |
c - geo #5 setup with only 3 Hall's sensors at the center (differential mode) or for plateform better than those using the geo #3 or #4. This setup works in geo #5 mode (levitated magnet at the center) or for a plateform (positioning magnet at the center and levitated magnets all around the plateform. The setups a & b allow the moving or the positioning of the levitated magnet at any place on the circle materialized by the 12 field coils, the 3 sensors at the center are not used in those setups. |
PHOTOS
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00040883
Recommended links :
Magnetic levitation - Science is fun (David Sligar's Science Site)
Magnetic levitation - Physic, Maths, Electronic and more (Barry's Site)
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