Estimate how far a belt moves during one drive-pulley revolution, its linear speed and its total travel over a chosen running time. Enter the effective pulley diameter in millimetres and the drive pulley’s rotational speed in revolutions per minute (RPM). Results assume no slip and constant speed.
- Enter the effective diameter where the belt travels around the drive pulley. Use diameter, not radius.
- Enter the drive pulley’s RPM after any gearbox or transmission reduction. The RPM entry is the number of revolutions completed in one minute; the calculator divides the corresponding travel by one minute to obtain speed.
- Enter the time for which the belt runs at that speed.
Distance per revolution is reported in millimetres, speed in metres per second, and total travel in metres. The one-minute travel result is a distance in metres; its numerical value also gives the speed in metres per minute.
| Result | Calculation | Rounded value |
|---|---|---|
| Travel per revolution | π × 100 | 314.159 mm |
| Belt speed | π × 100 × 120 ÷ 60000 | 0.628319 m/s |
| Travel in one minute | π × 100 × 120 ÷ 1000 | 37.699 m |
| Travel in five minutes | π × 100 × 120 × 5 ÷ 1000 | 188.496 m |
The calculation assumes a circular pulley, a constant effective diameter, steady rotational speed and no belt slip. Use the effective or pitch diameter appropriate to the belt system; the outside diameter may differ from the diameter governing belt travel. For a timing pulley, tooth count multiplied by belt pitch gives travel per revolution, and dividing that distance by π gives an equivalent pitch diameter.
The result excludes acceleration, stops, belt stretch and changes under load. Total travel is cumulative movement past a fixed point, not the belt loop’s physical length or the conveyor’s end-to-end length. Material travel matches belt travel only when the material does not slide relative to the belt.
Zero RPM gives zero speed and travel. Zero running time gives zero total travel while preserving the calculated speed. Diameter must be positive. Unavailable results indicate invalid or out-of-range calculations and must not be interpreted as zero.
Does one pulley revolution move the belt by its entire loop length?
No. With no slip, one pulley revolution moves the belt by the pulley’s effective circumference, π times its effective diameter. A marked point on the belt may require many pulley revolutions to complete one circuit.
Should I enter motor RPM or pulley RPM?
Enter the drive pulley’s actual RPM. Motor RPM is suitable only when the motor and pulley rotate at the same speed.
Why might measured belt speed differ from the result?
Possible causes include slip, an incorrect effective diameter, pulley RPM differing from the entered value, and changes in operating conditions. Compare measurements taken at the same operating speed and load.