Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Selecting motor and gearbox

Selecting motor and gearbox

Selecting motor and gearbox

I need to review some criteria for design of electrically-driven machines, especially for proper selection of electric motors and gearboxes.
I know some of this stuff from an university course that I took some years ago, in Italy. I have some resources in italian but now I would like to study from a textbook in english.
I searched very long without finding anything that fits. Is it possible that this topic is not covered in american/british engineering programs? It sounds very unlikely to me.
Could you please suggest a good textbook for mechanical or mechatronic engineering students about the design of electrically-driven machines? Thanks in advance!

RE: Selecting motor and gearbox

Other than the fundamental mechanics/dynamics of F=ma and T=Jα, textbooks probably won't be that useful for this application (IMHO). A useful summary I've recommended many times is The Smart Motion Cheat Sheet (websearch & find it somewhere).

Considering gearmotors, their task is to deliver a specified torque at a specified RPM. So your task is to calculate the maximum torque needed for your application. I suggest you find and study Engineering & Applications Guides from gearmotor manufacturers like SEW Eurodrive, Dodge, Nord, others. I recall that years ago SEW had a very detailed Engineering Guide used for sizing exercises for their gearmotors.

Blue Technik LLC
Virtuoso Robotics Engineering

RE: Selecting motor and gearbox

I'm not sure how much detail you want to go into for "selection of gearboxes", but "Shigley's mechanical engineering design" (10th ed, Budynas & Nisbett) has detailed chapters on gears and shafts. I found this very useful last year during a University project involving electric motors + gearboxes.

With regards to electric motor selection - I didn't find anything with detailed guidance for selection, but "Mechatronics" (6th ed, Bolton) was useful for understanding how each type works and some factors affecting selection.

RE: Selecting motor and gearbox

For the motors part, you could consider "Electric Motors and Drives" by Austin Hughes.
I second the vote for Shigley's book for the mechanics.


RE: Selecting motor and gearbox

Thanks for your valuable suggestions. I will read the references you recommended.
I also searched a little further by my own and I found "Mechatronics with experiments" by S. Cetinkunt. Section 3.6 is titled "Actuator sizing" and it seems ok, but I haven't read it carefully, yet.

RE: Selecting motor and gearbox


What is it you are trying to figure out? The mechanics of machines needed to understand gearboxes is not very complicated. An off the shelf gearbox is a black box, with gear ratio, efficiency, maximum speed, maximum, torque, mounting holes, and input and output shafts or connections. You should not really care what is inside.


RE: Selecting motor and gearbox

The horsepower of a gearbox has to match or exceed that of its drive motor.

RE: Selecting motor and gearbox

If you have a good understanding of the operating conditions for the machine being driven by the motor/gearbox, you can find a method for sizing the motor/gearbox on the website of most any commercial motor/gearbox manufacturer. Of course these OEM sizing methods will typically give a very conservative (but sensible) result, which you may not like.

RE: Selecting motor and gearbox

Quote (chicopee)

The horsepower of a gearbox has to match or exceed that of its drive motor.

And the torque capacity must exceed anything that can be applied externally.


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close