Working Magnetic Motor on you tube??

[MeggerMan]

@j7

Cheers

j7

@all

I am sorry that I failed mention that using bronze bearings will most likely require a very precise vertical mounting.

Cheers

j7

Perhaps surface tension is the wrong word, large area liquid/fluid friction perhaps?
Found an article for you:
http://www.nmbtc.com/pdf/forum/ball.pdf
Here's an idea:
1. Put a bronze slab onto a large flat bronze metal slope cover in sewing machine oil and see how quick the slab drifts to the bottom.
2. Take a hardened steel ball bearing placed on a stainless steel slope coated in sewing machine oil and see how quick the ball rolls to the bottom.

Another question, how many cars or lorries that you know of use bush/sleeved bearing for the wheel hubs - OK a lot of the engine parts run on bush type bearings, but then they do live in a world of oil. 

So in summary ball vs sleeve, the ball wins on the friction side for small devices, thats not to say the same is true for a 100 tonne rotor.
But go for it, build a sleeve version stator and see if its an improvement.


Regards
Rob

[Yadaraf]

.
I reanalyzed the FunkyJive enhanced audio from Al's first video.  This time I performed a power spectrum analysis (see below).

... Q:  If some one can explain why there is a 20dB increase at 172.3 Hz after the rotor accelerates, I'd appreciate it.   

Note that as the rotor accelerates there is not a frequency shift at 172.3 Hz like there is at 839.8 Hz, which increases to 861.3 Hz after acceleration [@ very end of video].  The increase in 21.5 Hz corresponds to an increase of 3000 RPM [stator].

Comments are welcome.

Cheers,

Yada..
.

[Omnibus]

@Yadaraf,

"Q:  If some one can explain why there is a 20dB increase at 172.3 Hz after the rotor accelerates, I'd appreciate it. "

Could it be that that's the stator bearing after it's latched at AGW rotation? When I get my rotor back (on Thursday, hopefully) I'll send you an audio sample with the stator latched in AGW rotation (not difficult to achieve after applying penetrating lubricating oil) to see if there would be such characteristic frequency at all, and whether or not it would increase after the AGW latch.

[Yadaraf]

@Yadaraf,

"Q:  If some one can explain why there is a 20dB increase at 172.3 Hz after the rotor accelerates, I'd appreciate it. "

Could it be that that's the stator bearing after it's latched at AGW rotation? When I get my rotor back (on Thursday, hopefully) I'll send you an audio sample with the stator latched in AGW rotation (not difficult to achieve after applying penetrating lubricating oil) to see if there would be such characteristic frequency at all, and whether or not it would increase after the AGW latch.

Omni,

I think you know this, but bear with me.  The left series of graphs is the result of sampling with three stators rotating -- with the primary stator latched AGW @1700 RPM -- right before Al stops two of the stators.  After Al stops two of the stators, the device accelerates, and both the rotor and stator increase in speed as observed in the freq shift from 839.8 Hz to 861.3 Hz.  The right series of graphs is the result of sampling at the very end of Al's video.

During acceleration and the 839/861 freq shift, the mode at 172.3 Hz remains fixed, but is amplified 20dB (a linear factor of 20/3 = 6X).  I'm really scratching my head about this amplification.    Previously, I suggested that this "lower" mode corresponded to bearing noise fom the slower-spinning rotor, but I do not believe that any longer.  Perhaps the material in the rotor or base plate is resonating like a speaker cone.  Perhaps something else in the room is resonating sympathetically. 

The amplification is very peculiar to me.   

For the fun of it, you might bombard your device with 172.3 Hz (174 Hz?) from a signal generator.  It "sounds" out there, I know.  I'll reanalyze the audio [again] tomorrow.

Cheers,   

Yada..
.

[JFK]

Hmmm, I don't know where Al is from, but that frequency is awfully close to the 2nd harmonic of the 60 hz "hum" from the power grid here in the USA.
Have no clue as to why there would be an increase in amplitude either.

- just throwing it out there.