DC motor - Enough torque to rotate load?

In summary, the torque of the gearmotor is 0.125Nm. The inertia of the cylinder is around 3.4 * 10^-5 Kg m^2. The drive shaft is around 1cm long. The cylinder is ~ 10cm long with a steel shaft put in its middle. Using a clamp at the base of the cylinder may be a viable option.
  • #1
dalou
3
0
Hi all,

I am new here as i want to ask something about an engineering project i am working on. I need a motor to rotate a 200 grams cylinder which will be hanging from the motor's shaft (vertically). I wanted less than 100 rpm so the motor I chose is a 2.1W 6V DC motor with a 50:1 reductor that leads to 60 rpm and 12.5Ncm. Will that be enough to keep that load rotating? I have no idea how much 12.5Ncm is and have nothing to compare it with. Moreover, what kind of coupling should I look for to fix the shaft of the cylinder to that of the motor? Will regular couplings be strong enough or will the cylinder fall down eventually? Thanks a lot for any responses, I really need your help here to make sure I won't buy anything wrong!
 
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  • #2
nothing? please any comment would be helpful, i really need an opinion here..
 
  • #3
dalou said:
Hi all,

I am new here as i want to ask something about an engineering project i am working on. I need a motor to rotate a 200 grams cylinder which will be hanging from the motor's shaft (vertically). I wanted less than 100 rpm so the motor I chose is a 2.1W 6V DC motor with a 50:1 reductor that leads to 60 rpm and 12.5Ncm. Will that be enough to keep that load rotating? I have no idea how much 12.5Ncm is and have nothing to compare it with. Moreover, what kind of coupling should I look for to fix the shaft of the cylinder to that of the motor? Will regular couplings be strong enough or will the cylinder fall down eventually? Thanks a lot for any responses, I really need your help here to make sure I won't buy anything wrong!

What's the torque of the gearmotor? The inertia of your cylinder? So the motor comes with a gear reducer or you're adding it yourself? Regardless, gearing it down will increase your torque; which you won't need much of once you get the cylinder actually moving.

Coupling depends on what it has to do. Regular coupling, what do you mean? Can you drill a holes into your cylinder and is it long relative to the drive shaft? If I could, I'd pin it right through the drive shaft (which will probably be pretty short), or use a set screw. If you can do a through-hole down the entire cylinder you can use a clamp at the base; whatever you want to do.
 
  • #4
First of all thank you for your response..

The gearing comes integrated with the motor. From the motor's datasheet:
Supply Voltage: 6V
Power Rating: 2.1 W
Output Ratio: 50:1
Output Speed: 60rpm
Torque: 0.125Nm (This number includes the gearbox, i.e. it is already increased due to the use of gerbox)

The inertia of the cylinder is around 3.4 * 10^-5 Kg m^2. Moreover, the cylinder will be dipped and rotating in an aqueous solution. And I don't mind about acceleration rate, as long as it is able to get started rotating.

The drive shaft is around 1cm long. The cylinder is ~ 10cm long with a steel shaft put in its middle. How would you fix the one shaft (that of the cylinder) to the rotating one of the motor. I had in mind something like that:
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=3258189#header
would that work ok? Or would the weight of the cylinder be too much to be supported by this?

Thanks a lot,

dalou
 
  • #5


Hello and welcome to the community!

Based on the information you provided, the DC motor you have chosen should have enough torque to rotate a 200 gram cylinder. 12.5Ncm (Newton centimeters) is a measure of torque, which is the rotational force needed to cause an object to rotate. In this case, the 12.5Ncm should be enough to rotate the cylinder at 60 rpm. However, it is always a good idea to double check the specifications of the motor to make sure it can handle the weight and speed requirements of your project.

As for the coupling, it will depend on the specific motor and cylinder you are using. Regular couplings may be strong enough, but it is best to consult with a mechanical engineer or refer to the manufacturer's recommendations to ensure a secure and safe connection between the motor and cylinder shafts. It is important to make sure the coupling can handle the weight and rotational force without slipping or breaking.

I hope this helps and good luck with your project!
 

1. How do DC motors produce torque?

DC motors produce torque through the interaction of an electric current and magnetic fields. The current flows through the motor's coils, creating a magnetic field that interacts with the permanent magnets attached to the motor's shaft. This interaction produces a force known as torque, which causes the shaft to rotate.

2. What factors affect the amount of torque a DC motor can produce?

The amount of torque a DC motor can produce is affected by several factors, including the strength of the permanent magnets, the number of coils in the motor, the amount of current flowing through the coils, and the size and shape of the motor's armature.

3. Can a DC motor produce enough torque to rotate a heavy load?

Yes, DC motors can be designed to produce enough torque to rotate heavy loads. The key is to select a motor with the appropriate specifications for the specific load, such as the required torque, speed, and power.

4. How do I calculate the torque required to rotate a specific load with a DC motor?

To calculate the torque required to rotate a load with a DC motor, you will need to know the weight of the load, the distance from the motor's shaft to the center of gravity of the load, and the speed at which you want the load to rotate. You can then use the formula Torque = Weight x Distance x Angular Speed to determine the necessary torque.

5. Are there any safety considerations when using a DC motor to rotate a load?

Yes, there are several safety considerations to keep in mind when using a DC motor to rotate a load. It is crucial to ensure that the motor is properly sized for the load and that all mechanical connections are secure. Additionally, proper grounding and insulation should be used to prevent electrical hazards. Regular maintenance and inspection of the motor are also important to ensure safe operation.

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