Working Magnetic Motor on you tube??

[Yadaraf]

hi everyone i was watching the video again and around 2:09 through 2:11  someone says something... does anyone know what he says?

http://www.youtube.com/watch?v=PIvZJ9xGutI

crash_uni8,

I struggled with Al's audio as well.  At 2:09 I thought he was taking a measurement and saying under his breath "that's not good."

After watching his process, reading the tach for myself, and listening carefully, I concluded the following:

... Stator speed: before stopping two of the stators: 1700 RPM

... Stator speed: after acceleration -- at very end of video:  4700 RPM

Let me know if you arrive at a different conclusion.

Cheers, 

Yada..
.

[MeggerMan]

@All,
I did some more tests and I have come to the conclusion that the bearings really need to made of something like aluminium alloy because even stainless steel is too magnetic and suffers from magnetic friction.

One alternate solution to ball bearing races is to mount the rotor magnet on a nylon shaft with two ribs top and bottom so the points of contact are minimal.  I found spinning a magnet on a 4mm nylon bolt is very good.
The bronze bush idea is suddenly looking very attractive I hate to say.

The sealed bearings out of a hard disk drive were very bad friction wise, I thought the ceramic bearing were cogging a bit with the magnets on top, but the sealed bearings were acting as it they were covered in syrup.

[edit] I found that one of the ceramic bearings had its teflon shield brushing the inner race causing very slight friction. The bearings with the rubber seal have, I think, a permanent contact with the inner race cause extensive friction. I guess the idea behind a double metal shield is to have a large overlap between the two shields to prevent dirt getting in and the lube getting out - yet there is no contact. [/edit]

I think my next step is to order some lightweight ali bearings:

Pictures of sealed ceramic 5x10x4mm and standard sealed 5x10.5x4mm bearings:



@Bruce,
Many thanks for sourcing the bearings - I look forward to getting more details on them.

Regards
Rob

[blue_energy]

@Yadaraf,

Here's the sample with my 266g rotor just for comparison. I know that 237g as was my other rotor and this 266g differ from the original but it isn't at all certain that the original is 258g because that's its weight without the red piece seen on top of it in the video. So. let's see what this sample will show and then I may revert back to the lighter rotor because achieving AGW here wasn't as easy at higher rpm.

Omni,

Attached is an analysis of the last file.  Neither of the last two audios are similar to Al's audio with respect to the dominant and dynamic 174 Hz tone.

Both audio files are fairly clean, but low in amplitude.  If you could locate the microphone closer, that might help.  Please remember to disable the AGC if possible.

If you can use two mics to monitor the stator and rotor separately, plug one into the LEFT channel [rotor?] and the second into the RIGHT [stator].   

Cheers,   

Yada..
.

After filtering out the noise in the sound track of Alsetalokin's first video, I enhanced the portion around 174 Hertz.  Then, independently, I produced a reference 174 Hz tone for comparison.  I noticed that there is no dominant tone on the video near 174 Hz until after the second acceleration - and it builds in frequency until it gets there as the rotor/stator speed up.  To check for sure that what I was hearing was correct, I superimposed the 174 reference tone against the enhanced portion of the audio at that point and played them back together. 

One of the interesting phenomema of sound is that, as two tones which are nearly the same pitch approach each other slowly, when they are almost 'in tune', audible phasing 'beats' are heard until they are exacly in tune - at which points the beats disappear.  The audio from Al's video and the 174 Hz reference tone, played together, exhibit this property as the rotor/stator speeds up until they are at their maximum rpm.  Only at this point do the beats cease. 

Please find an attached mp3 which demonstrates this.  The first 3 seconds are the 174 Hz reference tone.  Then, there is an excerpt from the enhanced audio at the point where the rotor/stator are approaching their maximum rpm.  You can hear an increasing tone that sounds as if it is approaching the same frequency.  Finally, the same excerpt superimposed over the reference tone.  You can hear the 'beats' speed up and finally disappear as the sound from the rotor approaches and lands on 174 Hz.

On the video, Al mentions that the final speed of the rotor is '...about 1,700 rpm'.  If it happened to be 1,740 rpm - then 174 Hz would be exactly 1 tenth of the speed of the rotor.  At that point it gets a little sticky though, because I can't think of an overtone/fundamental relationship which involves a 5.  But - it's been over 30 years since my 'Physics of Music' class - so maybe there is an explanation there.

[MeggerMan]

@Blue energy,
The MP3 was impressive - well done!

174Hz = 174 beats /second = 10440 beats / minute

8 rotor magnets passing the stator would give 1700 rpm x 8 / 60 =  226Hz

174Hz would imply a rotor speed of 1305 rpm and a stator speed of 5220 rpm.

Regards
Rob

[RunningBare]

@Blue energy,
The MP3 was impressive - well done!

174Hz = 174 beats /second = 10440 beats / minute

8 rotor magnets passing the stator would give 1700 rpm x 8 / 60 =  226Hz

174Hz would imply a rotor speed of 1305 rpm and a stator speed of 5220 rpm.

Regards
Rob

And would be much closer to ALs quoted stator/rotor speeds of 1250/5000