Choosing electric motor for rotating platform

Replies

• 

  praba230890

  Here the best motor that suits your problem is stepper motor. Because this is the only motor which you could control the by steps i,e by degrees using microprocessor's or microcontroller's which is programmed as per your requirements.
  
  

  Mr Zakaria

  Hi all,
  
  i want to build a solar tracker, which will have a platform, which will rotate in azimuth direction according to sun motion. The platform should have max tangential speed of 1.03 m/min (summer speed) and min tangential speed of 0.017 m/min (average speed). The platform will be put on wheels and the electric motor will be attached to the wheels. I will use 30cm diameter wheels for this application. For precision of 0.01 degrees, the wheel will have max 1.09 RPM and min 0.018 RPM. I have calculated the torque needed to accelerate the platform and also estimate the torque that needs to be overcomed due to friction. Basically, this is the total torque which i need to rotate the platform. My question is; how can i calculate the torque needed for the motor to drive the wheels? Can i just simply divide the total torque with the number of wheels used? The torque and RPM are needed to choose the suitable motor for the system. It would be also very helpful to me if you can suggest the supplier or which electric motor i should use for this application.
  
  Thanks in advance

• 

  Mr Zakaria

  Thanx praba230890.
  
  Does anyone know how to determine the torque needed for the motor which will drive the wheel, attached below the platform?
  Is it the same as torque needed to rotate the platform?
• 

  BarbarinoJiangxi

  Hello Friends,
  
  Thank you to your valuable suggestion. I think If you want to control the speed accurately you will probably need some sort of feedback control, in a closed loop system. A sensor gives the speed the platform rotates at, and this is compared with the desired speed. The error is used to adjust the motor speed. However, there are two other but related types of motors that will work. One is a stepping motor, the other is a synchronous motor. Both depend on being locked to a stable supply that generates pulses.
  
  
  Thanks lot
  Barbarino Jiangxi
• 

  praba230890

  If you added the toque due to friction and some other factors while calculation of wheel's required torque then it would be the same as the load torque. But i'm still unclear about this could you show us any diagrams of your setup that how you are going to connect the motor with the wheels and platform.
  
  

  Mr Zakaria

  Thanx praba230890.
  
  Does anyone know how to determine the torque needed for the motor which will drive the wheel, attached below the platform?
  Is it the same as torque needed to rotate the platform?