Magnetic levitation board not working

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HighTechPower
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Hi. I'm designing a magnetic levitation board based on schematics attached herewith. However it does not levitate the magnet. Plz note Q1 is P channel MOSFET. Also note that I used coil L1 as X1 & X2 and coil L2 as Y1 & Y2. Where Xs and Ys represents horizontal & vertical directions respectively. I think the original schematic has label errors for Xs and Ys as that confuse with horizontal and vertical directions otherwise I used same circuit. Another thing that I did not used R14, R16, C3, and C4.
 
Attachments
  • Circuit schematic of a magnetic levitation driver with two coil drive stages (Q2–Q5, Q6–Q9 with LM324 op-amps), a sensor-signal section with RP1 and RP2 trimmers, a 78L05 regulator, and a P-channel IRF9530 MOSFET stage.
    sch_3.jpg
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  • Circuit schematic of a magnetic levitation driver: three 49E Hall sensors (U1, U2, U3) with a J3 connector, a J2 connector, coils L1 and L2 with DL1, DL2, DL3 jumpers, and an LED array of LED1 to LED8 with resistor R1 (560).
    sch_4.jpg
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Last edited:
Welcome to PhysicsForums. :smile:
HighTechPower said:
However it does not levitate the magnet.
I'm no expert in Maglev, but if you are using AC magnetic field drive, you are intending to lift a conducting object via eddy currents, right? I don't think you lift a magnet using AC magnetic fields...
 
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Hi there. Now I also added the said resistors & capacitors however no success.
 
berkeman said:
lift a conducting object
and probably a non-magnetic one such as Aluminum?
 
Keith_McClary said:
and probably a non-magnetic one such as Aluminum?
Good question, but I don't know for sure. The demos that I've seen just used some metal plates, but I don't know if they were ferrous or not. Why would it matter with an AC magnetic field?
 
berkeman said:
but I don't know if they were ferrous or not. Why would it matter with an AC magnetic field?
Perhaps because AC levitation require interaction with the magnetic field from the current induced in the target object. A ferrous target will be attracted to the exciter magnet probably more strongly than the field from the eddy currents.

@HighTechPower, see if it will levitate a coin.

Referring to sch_4, any idea what the U1,2,3 sensors are? Do they detect light, or magnetic fields, or ?

Also, what are DL1,2,3?

Edit:
Looking at the circuit again I realized that it is a DC position servo. The U1,2,3 sensors are probably light sensors that detect when and how much the suspended object blocks light from the LEDs.

As such, a ferrous object is needed and following the original L1 and L2 connection instructions would be critical. I suggest you try their original configuration.
End Edit

Edit-2:
Also, trying to suspend a magnet will not work. A magnetic object will just spin in space and attract to the stronger field from L1 or, L2. (Might make an oscillator though!)
End Edit-2

Cheers,
Tom
 
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Finally it's success with some changes to the original circuit.
 
Tom.G said:
Please! Please! Details Please!
Well bro I made changes attached in pic herewith. I simply raised Vcc/2 from 2.5 V to 6 V while keeping signals from hall effect sensors at 2.5 V with this circuit. For this to happen please note that resistors R19 & R23 should be of same value and similarly R18 & R24 should be of same value.
 
Attachments
  • Schematic of an op-amp difference amplifier using an LM324: HE SENSE X input through R19 to inverting pin 2, +2.5 V REF through R23 to non-inverting pin 3, +6 V REF through R24 to the reference node, feedback resistor R18 from output pin 1 to pin 2.
    Changes.jpg
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I would like to see an image of the apparatus at work.
 
Keith_McClary said:
I would like to see an image of the apparatus at work.
Please see attachments.
 
Attachments
  • Green printed circuit board with a large brown ferrite ring core in the centre, four white cylindrical coils with screws at the top and bottom of the ring, and a red LED at the top right.
    Azeem's High Tech Power 41.jpg
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  • Photo of a green printed circuit board with a large rusty metal disc and a smaller grey disc held in place by cable ties over a stack of cylindrical magnets, with a yellow LED at top left and a red LED at top right.
    Azeem's High Tech Power 42.jpg
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  • Top view of a green printed circuit board with heatsinks along the left and right edges, electrolytic capacitors in the corners, two integrated circuit chips at the top, and a central mounting area with four potentiometers. The board is labelled Muhammad Azeem, High Tech Power, Islamabad.
    Azeem's High Tech Power 43.jpg
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  • Close-up photo of a levitation setup: a black ring-shaped magnet sits on a green circuit board, with several copper-wound coils on top and a black disc magnet floating above them.
    Azeem's High Tech Power 46.jpg
    56.9 KB · Views: 243
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Earnshaw's theorem proves that it is impossible for a static system using only paramagnetic materials (such as ferromagnetic iron) to levitate stably against gravity.
 
HighTechPower said:
Well bro I made changes attached in pic herewith. I simply raised Vcc/2 from 2.5 V to 6 V while keeping signals from hall effect sensors at 2.5 V with this circuit. For this to happen please note that resistors R19 & R23 should be of same value and similarly R18 & R24 should be of same value.
But we never knew those existed. o_O :cry: :cry:

Anyhow, Glad it works. And thanks for the feedback!

Cheers,
Tom