Self-sustaining DC Motor, using old 5 1/4" Floppy Drive Magnet

[pomodoro]

Hi Conrad, yes your post was what gave me the idea, I should have checked the link.  Have you any links for previous replications?

[conradelektro]

Hi Conrad, yes your post was what gave me the idea, I should have checked the link.  Have you any links for previous replications?

I did not find anything useful in the WWW. Aspden was active back in the nineties and nothing seems to have happened since.

I am building a contraption which will spin 6 magnets arranged in a hexagon (spin axis in the centre of the hexagon). The magnets can be oriented in various ways. But it will take some time, I am a slow builder.

Your posts inspired the idea that "spin down time from a certain speed" can also be used as a measurement method (instead of "spin up time to a certain speed"). Spin down is kind of easier to measure because the terminal speed does not have to be known precisely. One only has to assure that one starts the spin down always from the same terminal speed.

The terminal speed of a DC motor depends largely on the supply Voltage (which of course implies a certain Amperage). So, if one drives the "DC motor + magnet rotor" with a given Voltage (from a laboratory power supply) it should always spin up to the same terminal speed after a short time (hopefully in a few seconds).

Then the only variables are "length of time running" and "spin down time". Since "spin down time" will be rather long (many seconds) with a heavy rotor, differences should be pronounced (I hope).

Aspden also talked about orientating the contraption along a north - south - axis (or perpendicular to this axis). This only makes sense if one thinks about a "magnetic effect". If it is a "property of space", orientation of the contraption should not matter.

But may be the whole thing is nonsense. We will see. I will spin a "magnet rotor" and a "rotor without magnets". The rotor is made from plywood. If I manage to do some extended tests, I will also build a resin rotor with and without magnets (which will be heavy, about 1 kg).

It would help a lot if you did some spin down measurements with your set up. You could use a simple wooden disk as an alternative to your Floppy Drive Magnet just to see whether it spins down faster. You could use thin plywood and construct the disc with several layers of the thin plywood till the wooden disk has about the same weight than the Floppy Drive Magnet.

Greetings, Conrad

[MagnaProp]

Here is the motor in question...The fact that the upside down mounting is just as good probably means that the motor has very low friction and that the magnet is not interacting with it...

Thanks for the motor info. I agree with your preliminary assessment. sm0ky2 said he attached a non-magnetic flywheel to his set up and it didn't run as long. We unfortunately don't know what exact motor he used so maybe the windings in his motor caused a different effect? Sounds like it may be worth attaching a non-magnetic flywheel of the same shape and weight and see if the results are the same.

If you remove the yellow piece so the magnet is not attached to the motor shaft, do you notice a difference between running the motor with the magnet held in place by hand or removed?

Do any metal pieces stick to the shielded side of the magnet. Curious how much, if any, magnetism is getting through the shield?

[sm0ky2]

@pomodoro
   
     Excellent replication, I wondered if I could explain enough without actually still having the device in question.
that seems to be where I was at with it when I left off.



@MagnaProp

Thanks for the motor info. I agree with your preliminary assessment. sm0ky2 said he attached a non-magnetic flywheel to his set up and it didn't run as long. We unfortunately don't know what exact motor he used so maybe the windings in his motor caused a different effect? Sounds like it may be worth attaching a non-magnetic flywheel of the same shape and weight and see if the results are the same.

If you remove the yellow piece so the magnet is not attached to the motor shaft, do you notice a difference between running the motor with the magnet held in place by hand or removed?

Do any metal pieces stick to the shielded side of the magnet. Curious how much, if any, magnetism is getting through the shield?

The size seems similar in size to the motor I had but it was long ago (maybe a touch smaller than mine, but close),
one thing I can say the motor I used had two semi-circle permanent magnets on the inside surface, and the coil rotated there within.
   Knowing what I do about motor design, tells me this should not make a whole lot of difference. motors are designed in a number of variations, and combinations of electric and permanent magnetic fields, biasing, etc. but the general principal under which they operate remains the same, as Tesla has given us. Once operating, the coils induce a magnetic field in their counter-part. So, in essence, a coil-produced magnetic field is exactly the same as a permanent magnet of same field strength and dimensions.

I'm thinking more along the lines of the rotating field affecting the field interactions inside the motor, either by reducing/cancelling the back-EMF or something like that.

[Magluvin]

Here is the motor in question. There is a PDF that comes up with all the info you need, just google the part number.  I have not been able to do more tests as yet. The fact that the upside down mounting is just as good probably means that the motor has very low friction and that the magnet is not interacting with it. Anyhow, that my opinion.  I guess it would be worth while spinning the motor for a few minutes, stopping it by hand and using a charged up large capacitor to restart it. The repeating the process after a long rest, but with the cap only.  To see if Aspdens experiment can be replicated with this sort of weird magnet.  I wish he gave us more details.  Here is the best I could find .
http://www.scribd.com/doc/76567187/1995-Harold-Aspden-Discovery-of-Virtual-Inertia#scribd

That is a core less motor. The armature has no core. Just learned about these recently when I got into drones.  So without the core on the rotor itself, the core less motor is most likely quite different.

From the description of the original motor used, I would try Radioshack. 2 magnet halves and an armature, like we have all seen before. Just size will be the question now.

It seems odd, that if it works, the coils are not connected to anything(outside the motor at the terminals). But there is a connection made with the brushes as the rotor spins. A 3 pole motor shorts the windings at times, as do other motors with more poles, but the 3 pole does it for a longer period of rotation. The shorting is an inefficiency instilled into the design. So for me, eliminating the idea that the coils dont have anything to do with it is off the table for now. Just thoughts

Mags

Mags

Mags

I like that motor by the way. Core less are very efficient and very quick to accelerate or just change speed.