Selecting Motor for Project: Calculating RPM Requirements

  • Context: Undergrad 
  • Thread starter Thread starter kclouse
  • Start date Start date
  • Tags Tags
    Motor Project Rpm
Click For Summary

Discussion Overview

The discussion revolves around selecting an appropriate motor for a project involving the spinning of an aluminum disk at varying speeds between 400 and 3000 rpm. Participants explore motor specifications, types, and control mechanisms relevant to this application.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant suggests using brushless DC motors for precise speed control, though they note the importance of understanding the load on the motor.
  • Another participant raises the issue of friction losses, stating that if the disk is not touching anything other than its support, losses are minimal but difficult to calculate.
  • A suggestion is made for using a DC "outrunner" brushless motor, which is noted for generating more torque at lower rpm compared to conventional motors.
  • One participant provides details about the disk's specifications, indicating it will be 3.5 inches in diameter and 0.5 inches thick, milled to 1/32 inch thick, and coupled to the motor shaft.
  • A participant mentions that brushless motors require a controller for operation, which can also allow for varying rpm, highlighting the need for feedback mechanisms.

Areas of Agreement / Disagreement

Participants express varying opinions on the type of motor to use, with some advocating for brushless motors while others emphasize the importance of load considerations and friction losses. No consensus is reached on the best motor choice or specifications.

Contextual Notes

Participants do not fully explore the implications of load characteristics or the specific requirements for the controller, leaving these aspects somewhat unresolved.

kclouse
Messages
2
Reaction score
0
I'm trying to figure out how to select a motor for a project. I want to spin an aluminum disk between 400 and 3000 rpm. How would I go about calculating the correct specifications for a motor?

Thanks
-Kevin
 
Physics news on Phys.org
Since i don't know about your load. i suggest if you try with brush less DC motors because it is very good for precise speed controls.
 
Is this disk touching anything other than what is supporting it? If not, all losses are due to friction and those losses are extremely difficult to calculate (but are relatively small). Either way, if it is a small disk, a small dc motor will certainly give good speed control.
 
You'd probably want a dc "outrunner" brushless motor. These generate more torque at lower rpm than conventional dc motors. They're popular for radio control models. Do a web search for "radio control outrunner brushless motor" and you'll find quite a few site that sell these, along with specifications, like voltage, amps, torque, rpm, ...
 
Thanks all.

The disk will be made out of a 3.5 inch diameter .5 inch thick aluminum stock. It will be milled to 1/32 inch thick aside from the coupling that will attach directly to the motor shaft via two set screws.

I want to attach some kind of controller to the motor to allow roughly 100-300 rpm intervals from 400 to 3000 rpm.

The disk will be spinning perpendicular to the ground.

What do you think would work best?
 
Brushless motors already require a controller just to operate, and a typical controller allows the rpm to be varied. You just need some feedback from the controller or from the motor to determine and modulate rpm.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 6 ·
Replies
6
Views
8K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 12 ·
Replies
12
Views
11K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 16 ·
Replies
16
Views
9K
  • · Replies 4 ·
Replies
4
Views
2K