KEVOS® MAKEOS · Power Transmission
Belt Drive Tensions and Shaft Load
What belt tensions and shaft load are needed to transmit this power without slipping?
Effective pull, tight and slack side tensions at the slip limit, centrifugal tension and resulting shaft load of a flat or V-belt drive.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Power transmitted | kW | Design power (motor power × service factor). |
| Pulley pitch diameter | mm | Pitch diameter of the pulley being checked (usually the smaller one). |
| Pulley speed | rpm | Speed of that pulley. |
| Wrap angle on this pulley | ° | Arc of contact on that pulley (see the open belt drive tool). |
| Coefficient of friction | Belt-to-pulley friction coefficient from the belt maker. | |
| Groove included angle (0 = flat belt) | ° | Included groove angle for V-belts (about 34–40°); 0 for flat belts. |
| Belt mass per metre | kg/m | Belt mass per metre (all belts together) from the belt data sheet. |
Method and formulas
- Belt speed v = π d n ÷ 60 000; effective pull Fe = P ÷ v.
- e^(μₑθ) with μₑ = μ ÷ sin(β/2) for V-grooves; slack T₂ = Fe ÷ (e^(μₑθ) − 1) + m v²; tight T₁ = T₂ + Fe.
- Shaft load = √(T₁² + T₂² − 2T₁T₂ cos θ) with the centrifugal part removed.
- Example: 7.5 kW on a 160 mm pulley at 1450 rpm needs T₁ = 689.81 N and T₂ = 72.403 N, loading the shaft with 702.58 N.
Limitations
- Tensions are at the slip limit; install with a margin (the belt maker’s recommended static tension).
- Belt bending and fatigue are not checked.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Set belt tension for a drive
- Find bearing loads from a belt drive
- Check whether a drive will slip
Who it is for
- Design engineers
- Maintenance engineers
- Automation engineers
What you get
- Belt speed
- Effective pull
- Tight and slack side tensions
- Centrifugal tension
- Shaft load
Interpreting the result
- Use the belt maker’s tension figures for installation; this result shows the minimum to avoid slip.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2473–2520. Topic reference; no source tables or recommended settings are reproduced.
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