Enter the motor (driver) speed (RPM) and the driven (output) speed (RPM) into the Sheave Ratio Calculator. The calculator will evaluate and display the Sheave Ratio.
Sheave Ratio Formula
The following formula is used to calculate the Sheave Ratio.
SHR = MS / OS
- Where SHR is the Sheave Ratio (dimensionless)
- MS is the motor (driver) speed (RPM)
- OS is the driven (output) speed (RPM)
To calculate the sheave ratio, divide the motor (driver) speed by the driven (output) speed. For a belt-and-sheave (pulley) drive with negligible slip, this speed ratio also equals (driven sheave pitch diameter) ÷ (driver sheave pitch diameter).
How to Calculate Sheave Ratio?
The following example problems outline how to calculate Sheave Ratio.
Example Problem #1:
- First, determine the motor (driver) speed (RPM).
- The motor speed (RPM) is given as: 50.
- Next, determine the driven (output) speed (RPM).
- The driven (output) speed (RPM) is provided as: 20.
- Finally, calculate the Sheave Ratio using the equation above:
SHR = MS / OS
The values given above are inserted into the equation below and the solution is calculated:
SHR = 50 / 20 = 2.5
Example Problem #2:
For this problem, the variables required are provided below:
motor speed (RPM) = 60
driven (output) speed (RPM) = 10
Test your knowledge using the equation and check your answer with the calculator above.
SHR = MS / OS = ?
