Sheave Ratio Calculator

Motor Speed (RPM): Gear Drive Output Speed (RPM):

Created by Team y2calculate

Content written by Jane (Ph.D.)

Coding and design by Marcelino (Ms)

Reviewed by David (Ph.D.)

Fact checked 🔍✓

[post_dates]

What is Sheave Ratio?

The Sheave Ratio (SHR) is a measure used in mechanical systems, particularly in machinery and power transmission setups. It represents the ratio of the motor speed (MS) to the gear drive output speed (GS). The Sheave Ratio is expressed mathematically as:

In simpler terms, the Sheave Ratio describes the relationship between the rotational speed of the motor and the rotational speed of the gear drive output. It provides a numerical value indicating how many times the motor must rotate to produce one complete rotation of the gear drive output.

sheave ratio formula

Sheave Ratio (SHR):
- A measure that shows how many times the motor must rotate to produce one complete rotation of the gear drive output.
Motor Speed (MS):
- The speed at which the motor is rotating, measured in revolutions per minute (RPM).
Gear Drive Output Speed (GS):
- The speed at which the output shaft of the gear drive is rotating, also measured in revolutions per minute (RPM).

why do we need sheave ratio?

The Sheave Ratio serves several important purposes in mechanical systems:

Control of Rotational Speed:
Transmission Efficiency:
Torque Matching:
System Design and Optimization:
Equipment Synchronization:
Energy Efficiency:
Troubleshooting and Maintenance:

How to calculate Sheave Ratio

Calculating the sheave ratio is simple, for the sake of simplicity we have made a share ration calculator for it, but for those who want to calculate the sheave ration manually than divide Motor Speed (RPM) by Gear Drive Output Speed (RPM).

Example how to find sheave ratio

let’s go through a couple of examples of how to find the Sheave Ratio:

Example 1: Conveyor System

Suppose you have a conveyor system with a motor rotating at 1200 RPM and a gear drive output spinning at 300 RPM. To find the Sheave Ratio:

In this example, the Sheave Ratio is 4, meaning the motor must rotate four times to complete one rotation of the gear drive output.

Example 2: Industrial Mixer

Consider an industrial mixer where the motor operates at 1500 RPM and the output shaft of the gearbox turns at 250 RPM. The Sheave Ratio is calculated as:

Here, the Sheave Ratio is 6, indicating that the motor must make six revolutions for every rotation of the gearbox output shaft.

These examples illustrate how to apply the Sheave Ratio formula to real-world scenarios, helping in the design and understanding of mechanical systems.

What indicates higher and lower sheave ratio?

Higher Sheave Ratio:
- A higher Sheave Ratio indicates that the motor must rotate more times to achieve one complete rotation of the gear drive output. For example, a Sheave Ratio of 8 means the motor has to make eight rotations for each rotation of the gear drive output. Higher Sheave Ratios are associated with a slower output speed compared to the input speed.
Lower Sheave Ratio:
- Conversely, a lower Sheave Ratio implies that the motor requires fewer rotations to achieve one complete rotation of the gear drive output. For instance, a Sheave Ratio of 2 means the motor completes one rotation for every two rotations of the gear drive output. Lower Sheave Ratios are associated with a faster output speed compared to the input speed.