Hi guys i'm in search for a dc motor which is capable of handling 100kg of weight. it will be using a radial load and no axial load will be applied to it. or if there is a motor with which can handle axial load then much better. the speed is 50-90 rpm
My plan is a pulley will be attached to the motor shaft and another pulley attached to a tube will be placed in the pivot point of the object holder. then it can be control to increase and decrease speed of motor and reverse the direction of the motor.
Also how can i control this motor with arduino?. I only know how to use L293D and SN75. What if the motor have higher current then i can't use the following.
If you look for sales and such, you might get a winch like below for cheap. A couple years back I got the bottom winch for $40 and have seen recently the winch in the link on special sale for ~$50.
one other alternative that you could look into is the motor that cars use for the automatic window. it have some serious torque, however i dont think that the motor is capable of the speed you want. or you could actually use a very fast motor and use gear/belt system that could reduce the speed to exchange with torque.
endl3ss:
Hi guys i'm in search for a dc motor which is capable of handling 100kg of weight. it will be using a radial load and no axial load will be applied to it. or if there is a motor with which can handle axial load then much better. the speed is 50-90 rpm
If you are wanting to handle a radial load of that magnitude, you are going to want radial ball bearings on the output shaft (probably on both ends of the motor shaft - front and rear housing); if you can't get that, then mounting the motor and driving a jackshaft that has such bearings will work, too. The idea is that you need such ball bearings for the load, because without them, the motor will fail quickly (ie - bushings are -not- going to work).
endl3ss:
My plan is a pulley will be attached to the motor shaft and another pulley attached to a tube will be placed in the pivot point of the object holder.
Maybe you should draw us a diagram, because I certainly was unable to understand what this means, exactly...
Well - you could modify such a servo to be continuous rotation - but that servo is unlikely to serve your purposes, unless your pulleys are only a couple of centimeters in diameter.
The person who mentioned that we need to know your pulley diameter in order to be able to determine an appropriate motor was right; it also appears you don't have an understanding of what torque means.
In the case of this Pololu servo, it has 115 kg-cm torque. What this means is that if you had a lever mounted on the shaft, that sticks out 1 cm from the centerpoint of the shaft, and you hung a 115 kg weight from the end of that lever, the servo could move it. Thus my comment about a pulley 2 cm in diameter, because that would be the max size of pulley you could use (because a pulley is nothing more than that circular lever). If you used, for instance a 4 cm diameter pulley (thus, a lever 2 cm long) - your torque would be decreased by half; you could only lift a 57.5 kg weight. If your pulley was 1 cm in diameter (ie, a 0.5 cm lever), you could lift double the weight (230 kg). Do you understand how that works?
Note that in reality you are very unlikely to see such results; just like any other part specification, these specs are "ideal world" specs, and you never want to run near them - so plan for a motor with a spec 15-25% bigger than what you think you need.
Now this motor is likely waaaay beyond anything you need. Note the spec on it: 1000 foot-pounds! What this means is that if you attached a pulley 2 feet in diameter (ie - a lever one foot long, or about 30 cm), you could life 1000 pounds (approx 453.5 kg) with it! That goes way, way beyond anything you need (and, given that this is an industrial spec motor - I doubt that it is cheap to purchase, especially in single quantity).
endl3ss:
Also how can i control this motor with arduino?. I only know how to use L293D and SN75. What if the motor have higher current then i can't use the following.
Well - you use an h-bridge (and power supply) sized for the motor, of course. Let's say you did purchase the above planetary gear motor. That uses this motor:
Unfortunately, everything on that site is generalized - this is more the kind of motor you go to the company and say "Hey, I have this application - can you size me a motor and controller for it, I thought that maybe the DM40 might be a good fit - I want to run at 24 VDC..."; then you throw them a wad of cash ($10k USD or so to start, maybe) - and you work with them to help you design the product.
Note that they sell motor controllers for their motors:
...though they don't seem to be available for the DM40 - but I bet they sell something; they do give an idea of what kind of current to expect - say at 12 VDC, somewhere around 25 amps or so.
You would want to use a very beefy DC power supply (on the cheap, an automobile starter/charger supply could work, short term - not continuous duty, of course); and a very beefy h-bridge motor controller (probably something around 30-50 amps); there are a few out there that aren't terribly expensive (I think Pololu might sell one or two; there is also this company:
...hardly inexpensive, though. If you do some research, you can find relatively cheaper brushed DC motor controllers that can control such beefy motors...