Rotation design


by dt1156
Tags: design, rotation
dt1156
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#1
Apr18-13, 11:45 PM
P: 3
Hey guys looking to design something that will rotate a 2kg discus in place. I attached a simple schematic of what it will look like. I also don't know what kind of motor to use to rotate the shaft. I went to Fry's but their motors looked to weak to power it. Anyone know a site I can buy a motor that can get the job done for me?
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NascentOxygen
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#2
Apr19-13, 12:16 AM
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Quote Quote by dt1156 View Post
Hey guys looking to design something that will rotate a 2kg discus in place. I attached a simple schematic of what it will look like. I also don't know what kind of motor to use to rotate the shaft. I went to Fry's but their motors looked to weak to power it. Anyone know a site I can buy a motor that can get the job done for me?
Hi dt1156!

One major omission in your specifications: the speed range over which you wish to spin it. Also, would be worth pointing out your discus's diameter.

Are you planning mains operation, or a low voltage? My first thought is a ceiling fan motor and speed controller, but take great care, because a smooth discus is going to offer far less resistance than a big fan, so the discus will have a much faster top speed. This could be dangerous.

To what purpose will you put this spinning disc?
Danger
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#3
Apr19-13, 02:48 AM
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A fan is a good idea. My first thought was to hit a surplus store or scrapyard and grab an old vinyl record turntable. You already have 2 or maybe 3 mechanically selectable speeds, with the option of adding an electronic controller. It has the advantage of needing only a restraint such as a couple of straps or some Velcro as opposed to an entire mounting system.

dt1156
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#4
Apr19-13, 02:33 PM
P: 3

Rotation design


Quote Quote by NascentOxygen View Post
Hi dt1156!

One major omission in your specifications: the speed range over which you wish to spin it. Also, would be worth pointing out your discus's diameter.

Are you planning mains operation, or a low voltage? My first thought is a ceiling fan motor and speed controller, but take great care, because a smooth discus is going to offer far less resistance than a big fan, so the discus will have a much faster top speed. This could be dangerous.

To what purpose will you put this spinning disc?
The discus's diameter is 9in, 5/16" screw size and weights 2kg and round shape. I've included a picture of a discus that looks very similiar to mine. The point of this design is to create a test to gather data from the discus while it is in rotation without having anyone actually throw it. This is a group project where my group will be placing an acceleramator inside the discus and a programming a microcontroller to convert the acceleration readings into the distance the discus traveled. I'm just designing this rotational test part.
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NascentOxygen
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#5
Apr19-13, 08:28 PM
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.... One major omission in your specifications: the speed range over which you wish to spin it.
dt1156
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#6
Apr21-13, 12:47 PM
P: 3
Not much faster than the average rotational speed of a discus thrown by a olympic athelte. I couldn't find any measurements of a discus thrown by olympians so I asked my group and someone took a guess at around 10 revolutions per sec which is around 62 rad/s.


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