URGENT!!!!!! HELP!!!!! about DC Motors

[Sean Baltagi]

I'm in a bind!!! let me explain. i'm trying to make a rotating display for a project i have to do for my architecture class. i made a table that is 40" square, then i have a 1/4" thick plexi that was routed to 36" round. I wanted the plexi to sit flush with the wood, so i routed 36 1/4" circle into the table i made, the rout was 1/4" deep. now to the problem. How can i rotate it? i need a motor that rotates no more than 4 RPM and has high torque. The plexi alone weighs 12 lbs. so i need the motor to be able to carry and rotate at least 20lbs. ANy help on how i can make this thing rotate would be greatly appretiate!!!! my presentation is monday night!

Thanks

Sean

 

[Tom Schindler]

You could buy a higher RPM motor and gear it down.





Tom

 

[Jeff C]

Go to your local hobby shop and look at brushless motors and see if you can get an ac/dc converter. When you find a motor, you'll likely have to fit it with gears of some sort. That way you can have a high speed, high torque motor, and just gear it large enough so that it spins slow.

 

[Gavin Allan]

You need to rest it on several ball bearings underneath. The bearings will support the weight, but let it spin easily.



As for rotation, you are going to have to gear it down somehow.



If you had a center spindle, you could cut gear teeth in the side of the platter and drive it from a pinion gear mounted on the motor shaft. Another way might be to make a belt-drive arrangement with a long belt around the platter.



This is gonna be a hard one to pull off over the weekend.

 

[Kevin Palmer]

Go to a salvage yard, AKA junk yard and buy a Windshield Wiper Motor. Lots of torq so it will be able to handle the load.



The ball bearing suggestion is a good idea as it will take the lateral torq off the motor.

It may spins to fast for your needs. You can do one of two things.



Get a resister to slow it down, just like the wiper unit uses in your switch or mount a gear to it as well as the table your spinning.



Little gear on the motor, bigger gear on the table.

 

[roger Biddlecombe]

try getting a lazy susan, get 18in dia , set your disc on it, [craft store],use wiper moter and mount wooden disc with groove on edge to fit shaft ,make several dias ,1.5in to 2.5in, put groove in edge to take 0ring,mount under outer edge,apply power it will work, it is simple no gears etc ,Roger

 

[Richard L]

Yep, gears, different size pulleys, sprocket and chains.

You might even want to look at a direct drive system that uses very small rubber wheel on the motor and it makes friction contact with the underside of the turntable. The further you move the motor towards the outer parimeter of the turntable, the slower the turntable will turn. You could calculate the rotation of the turntable using the circumference of the motor mounted wheel and the circumference of the turntable depending upon where the motor wheel contacts the underside of the turntable.



...Rich

 

[ReggieMRegalOne05 Legaspi]

Ever thought of old ponograph motor? The old, portable, battery powered ones. Pawnshops or thrift shops might still have one laying around.

 

[Andy G]

www.jameco.com



They carry motors with attached geardown boxes in the $20 ballpark.



When you get to their website, click on "electromechanical", then "motors" then "gearhead". Then at the next page, do not select any parameters and just click "show results". This will give you the entire selection of high torque, geared motor/boxes.



best of luck on your project



cheers,