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Author Topic: Motorized top  (Read 4626 times)

ta0

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Re: Motorized top
« Reply #30 on: June 03, 2020, 09:40:56 PM »

Q1: How does the metal tip connect to the rest of the Infini-Top? Fixed to the round black chassis fixed to the motor casing?
Q2: Same question for the triangular black part with the large white nylon gear at its center? Is the big gear keyed to the upper blue shell half, or do they connect through a frictional pivot bearing with potential slip? And what other connections to the black part itself -- besides the gears?
The tip is fixed to the black casing.
The axle of the big gear is keyed to the blue shell. The only other point of contact is the hole through which the tip goes through the shell. Actually, there is also a round free spinning piece that serves to push the blue on-off switch when you press down on the top.



But the top seems rough, we don't know if this is a real and working motorized top.
The Infini-Top precesses clockwise or counterclockwise ?

The Infini-Top with the full shell and good batteries works very well. As you can see at the end of the video below, it will rise by itself from a laying down position.
It precesses clockwise, like the black internal part that carries most of the weight.

https://www.youtube.com/watch?v=GwE9MOdZ5l8

Filmed at 240 fps. Thanks to the LEDs we can follow the internal black casing without removing part of the shell. You can see slow motion (1/20 X) at about 0:30 and 4:30. The rotational speed remains pretty consistent, at about 1600 RPM clockwise for the black case and 720 RPM counterclockwise for the blue shell.

By the way, it took me a while to figure out how to change the batteries!  :-[ Each time I replaced the original Chinese "Dureday" brand batteries which were pretty empty with fresh Duracell batteries, it stopped working!  :-\ When I finally realized what was going on, I remembered that it had happened to me once before. Chinese batteries have longer nipples (you can say they are perkier  :P ) and reach the positive contact, while American (at least Duracell) batteries might not (by a fraction of a mm, so not easy to see).  >:( I had to add aluminum foil to two contacts to have it working.
« Last Edit: June 04, 2020, 12:04:18 AM by ta0 »
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Jeremy McCreary

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Re: Motorized top
« Reply #31 on: June 03, 2020, 11:21:56 PM »

Resembles Iacopo's motorized top, but without the fairing around the flywheel...

https://youtu.be/jbIvO87eiIY

The thin power supply wires keep the tip from slipping relative to the table, much as tip resistance does in Iacopo'a case.

But the dynamic's basically the same: With the tip-bearing chassis containing the motor casing prevented from turning for whatever reason, the motor keeps enough angular momentum in the flywheel to stabilize the entire assembly against gravity.
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Art is how we decorate space, music is how we decorate time ... and with spinning tops, we decorate both.
—after Jean-Michel Basquiat, 1960-1988

Everything in the world is strange and marvelous to well-open eyes.
—Jose Ortega y Gasset, 1883-1955

ta0

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Re: Motorized top
« Reply #32 on: June 03, 2020, 11:33:04 PM »

But the dynamic's basically the same: With the tip-bearing chassis containing the motor casing prevented from turning for whatever reason, the motor keeps enough angular momentum in the flywheel to stabilize the entire assembly against gravity.
From what I see on the video, it appears just as a gyro. I don't see proof that it's a rising top.
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Jeremy McCreary

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Re: Motorized top
« Reply #33 on: June 04, 2020, 12:13:20 AM »

But the dynamic's basically the same: With the tip-bearing chassis containing the motor casing prevented from turning for whatever reason, the motor keeps enough angular momentum in the flywheel to stabilize the entire assembly against gravity.
From what I see on the video, it appears just as a gyro. I don't see proof that it's a rising top.

Fair enough, but doesn't that make Iacopo's motorized top just a gyro, too? I wasn't implying anything about rising.

Thanks for all the info on the Infini-top! That last video was especially helpful. I really need to invest in a decent slo-mo camera.

For an onboard motor in a free-standing top to counter spin decay until the battery dies, the motor must ultimately get purchase on the outside world through either tip or air resistance. In the Infini-Top, the dominant purchase is the air resistance on the shell -- which has a lot of exposed surface area and relief to make up for its low air speed. Fair statement?
« Last Edit: June 04, 2020, 12:17:41 AM by Jeremy McCreary »
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Iacopo

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Re: Motorized top
« Reply #34 on: June 04, 2020, 02:31:41 AM »

Resembles Iacopo's motorized top, but without the fairing around the flywheel...

https://youtu.be/jbIvO87eiIY

The thin power supply wires keep the tip from slipping relative to the table, much as tip resistance does in Iacopo'a case.

From what I see on the video, it appears just as a gyro. I don't see proof that it's a rising top.

Yes, this one is similar to the mine, and, like the mine, it is unstable, it slowly sinks down by the time, and never rises.
In fact the tip, in both the tops, rolls in the "wrong" direction, opposite to that of a normal spinning top, and the rolling resistance is in direction to make the top to sink down and not to rise. 
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Iacopo

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Re: Motorized top
« Reply #35 on: June 04, 2020, 04:16:24 AM »


But the top seems rough, we don't know if this is a real and working motorized top.
The Infini-Top precesses clockwise or counterclockwise ?

The Infini-Top with the full shell and good batteries works very well. As you can see at the end of the video below, it will rise by itself from a laying down position.
It precesses clockwise, like the black internal part that carries most of the weight.

Sorry, I haven't thought that the Infini-Top too is blue, but I was referring to the other blue top, the rough hand-made blue top of the video posted by Jeremy.
I never doubted that the Infini-Top is a functioning and effective motorized top.

The Infini-Top seems to behave quite similarly to a normal spinning top;
the tip is attached to the black chassis, which is the heavier part of the top, so the top walks and precesses in the same direction, (clockwise), like a normal top.
The tip rolls in the correct direction for the rise of the top, like in normal tops.
Vibration seems not necessary in this top.

Then there is a lightweight casing, pushed backwards, (counterclockwise), by the black chassis, through the motor.
The casing, for reaction, gripping on the air, pushes the black chassis clockwise, through the motor.  This keeps the top spinning by the time.
It's a bit like a swimmer, who moves backwards his arms into the water, (the light casing into the air), and, for reaction, the body of the swimmer is pushed forward, (the black chassis is pushed clockwise).
If I remember well, you already gave a similar explanation, which I believe it is correct, at least for this motorized top.

The rotational speed remains pretty consistent, at about 1600 RPM clockwise for the black case and 720 RPM counterclockwise for the blue shell.

So the black chassis, through the motor, spins the casing at 2320 RPM.
1600 and 720 RPM are the speeds at which the torques of air drag and tip friction find an equilibrium and have the same magnitude.


But I can't understand yet the toupie lumineuse.  Not even having it in my hands.  The tip here is part of the casing, so the tip friction can't be used for to push the casing backwards against the air and keep the top spinning.
« Last Edit: June 04, 2020, 04:27:04 AM by Iacopo »
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Jeremy McCreary

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Re: Motorized top
« Reply #36 on: June 06, 2020, 02:23:39 PM »

Another motorized top -- the hard-to-find and rather clever "Toop", ca. 2012...

https://youtu.be/nkdxKbmmjCg

Nice to know that cool people play with tops, too. Love the name "Toop".

Guessing that the motor spins the body of the Toop against the drag on the T-handle/impeller above.

https://youtu.be/RkIarQQJRDQ

Beyond the usual free-standing and battle top action, lots of additional play value in the lighting, the handle, the magnetic tip and stem, the stacking, and the magnetic wand manipulation from above or below. Also, lots of potential for experimentation.

After all, the only thing better than watching a top spin is messing with it.
« Last Edit: June 06, 2020, 10:26:42 PM by Jeremy McCreary »
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ta0

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Re: Motorized top
« Reply #37 on: June 07, 2020, 08:18:18 AM »

Another motorized top -- the hard-to-find and rather clever "Toop", ca. 2012...
We have discussed the Toop (link) and it's (now beaten) Guinness record before. Looking at that previous thread, I remembered that's when I first found the battery nipple problem.  :D
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Iacopo

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Re: Motorized top
« Reply #38 on: June 07, 2020, 01:52:36 PM »

The Toop and the Infini-top seem two motorized tops of the same kind, working in the same way.
The Toop uses the blades to keep moving, and the Infini-top uses the casing instead of the blades, in the same way.
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