How to calculate the rpm of a motor and speed reducer

Written by andrea helaine
  • Share
  • Tweet
  • Share
  • Pin
  • Email
How to calculate the rpm of a motor and speed reducer
In a speed reducer, the motor turns the small cog that turns the large cog to reduce the speed. (Large and small Cog Wheels together. image by daseaford from Fotolia.com)

Motors run at a specific revolutions per minute (RPM) and a speed reducer is needed if you want to keep that motor, but have a lower RPM. Calculating the RPM resulting from a motor and speed reducer assembly requires only basic mathematical knowledge.

Skill level:
Easy

Other People Are Reading

Things you need

  • Motor base RPM
  • Speed reducer ratio

Show MoreHide

Instructions

  1. 1

    Write down the rated RPM of your motor; for example, 5000 RPM.

  2. 2

    Write down the ratio of the speed reducer; for example, 12:5.

  3. 3

    Calculate the reduction by dividing 12 by 5, which equals 2.4.

  4. 4

    The RPM of the assembly is the RPM motor divided by the reduction. In our example, it would be 5000 RPM/2.4 = 2083 RPM.

Tips and warnings

  • The ratio of a reducer will always be in the form of A:B, where A>B.
  • The RPM found should always be lower than the base RPM of the motor. If it is not, either redo your calculation or make sure you did not get a speed multiplier instead of a reducer.

Don't Miss

Filter:
  • All types
  • Articles
  • Slideshows
  • Videos
Sort:
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the eHow.co.uk site, you consent to the use of cookies. For more information, please see our Cookie policy.