Hall-Effect Sensor Levitator

I had heard the brushless motors in floppy drives and CD-ROMs contained hall-effect sensors, and looking for an excuse to build a better levitator I started experimenting. The sensors found in brushless motors are linear, symmetric devices, and perfectly suitable for small levitators. This levitator uses PWM to control the electromagnet, and thicker wire, so it's much more efficient than my previous model. The amount of heat generated when levitating an object is so tiny it can run indefinitely.

Construction details here: http://uzzors2k.4hv.org/index.php?page=magneticlevitation

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Science & Technology

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• Uzzors2k

[a1mint]

How many Watts does it use. Interested to know if because it generates so little heat, that the energy used is so little.

Also, what if you put a delay in the sensor reaction. The object would start moving up and down, performing more work. Would that generate more heat?

[Uzzors2k]

@a1mint I haven't taken any measurements of power consumption, though that would be interesting. IIRC my infrared levitator used about 15-20W of power to levitate 100 gram objects, though this was with the aid of a magnet. A delay or other imperfection in the regulation loop would indeed increase power usage, since the object would be constantly accelerated up and down. The large bouts of force needed from the electromagnet would require current surges, which represent a R*I^2 loss.

[a1mint]

@Uzzors2k The interesting part is, I think, and correct me if I'm wrong, the act of keeping the object levitated can take next to not energy, because no work is being performed. The potential energy of gravity is being opposed.

If that weren't the case, and if it takes (a lot of) energy to keep an object afloat, then using permanent magnets would spend energy, which it doesn't because permanent magnets can not be a source of energy.

[Uzzors2k]

@a1mint According to my understanding of physics the actual levitation doesn't require energy like you say. However the process of creating the magnetic field required to suspend the object does, but only through resistive losses in the electromagnet. Theoretically by using a superconducting electromagnet, you wouldn't require energy to suspend an object.

[a1mint]

@Uzzors2k So, an interesting application would be an (electric) magnet monorail of sorts that hangs off a metal railing. The magnet would keep the train near, but not touching, the rail. Safety wheel on top would ensure the train can't fall down. Energy would be fed through the rails. The train would pick that up through induction. The train can use part of its energy from its momentum somehow, so that even when power fails it can coast while still floating...

Just a wild idea.

[Uzzors2k]

@a1mint I think I've heard of this before as an application of room-temp superconductors. It'd be sort of like those levitation demonstrations using pyrolytic graphite, liquid nitrogen and magnets.

[nilesh066]

How you tune the PID controller for the levitation?

[a1mint]

@Uzzors2k Indeed. What about using an AC power source?

[blivori]

what hall effect sensor did you use?? and how many coil windings?

[seonsshrestha]

where's the video discription?