CORE PRINCIPLES
What to establish first
- Transmitted power comes from the tight-side and slack-side tension difference.
- Belt speed is set by pulley diameter and rotational speed.
- Initial tension and wrap angle influence traction and bearing load.
Belt Drives
Belt speed, tension, power capacity and pulley calculations.
MODULE OVERVIEW
Belt Drives in practical engineering work.
Belt drives provide flexible power transmission and tolerate some centre-distance variation. Their capacity depends on belt speed, tension difference, pulley diameter, wrap, alignment, temperature and the manufacturer's rating method.
DESIGN CONCEPTS
Terms worth checking
- Belt speed
- Tension ratio
- Wrap angle
Common applications: Fans · Machine tools · Light conveyor drives
KEY RELATIONSHIP
Belt power relationship
P = (T₁ − T₂)v
- T₁ — tight-side tension, N
- T₂ — slack-side tension, N
- v — belt speed, m/s
The equation does not rate a belt; use supplier data for flexing, temperature and service-factor limits.
WORKED EXAMPLE
Known values → substitution → interpretation
- Known values
- T₁ − T₂ = 400 N; v = 8 m/s
- Method
- P = 400 × 8
- Interpretation
- The ideal transmitted power is 3.2 kW before drive losses.
KEY DESIGN CHECKS
Confirm the conditions behind the number
- Define the governing load case, duty cycle and required design life before using a simplified relation.
- Use compatible units and material data for the actual condition, temperature and manufacturing state.
- Compare the result with strength, stiffness, fatigue, safety, serviceability and applicable-code requirements.
COMMON ENGINEERING MISTAKES
Keep the model within its scope
- Applying belt power relationship outside the assumptions shown on this page.
- Using a nominal condition while a peak, alternating, transient or environmental case governs the design.
- Treating a calculated value as a final component selection without checking interfaces, tolerances and the current governing standard.
AVAILABLE CALCULATORS
Select a calculator
Engineering guide resources
This source-aware module explains the governing relationship, design checks and practical application. Use the related resource below or continue to the calculator library for an interactive calculation.
RELATED RESOURCE
Review torque and speed
Use the torque relationship before selecting a belt-drive stage.
Open related resource →REFERENCES & LIMITATIONS
Use this content as a transparent starting point
ReferenceISO 4184 and belt-manufacturer engineering manuals for sizing and rating procedures.ScopeRelationships are presented for the assumptions stated on this page and linked tool.Design reviewCheck material condition, loads, environment and the applicable current code.SafetyResults are educational/preliminary and do not certify safety or compliance.
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