Pulley Ratio

Determine driven shaft speeds and belt surface velocities for V-belt and timing belt power transmission.

Sheave Dimensions
Motor Speed
Speed Ratio
: 1
Output Speed
RPM
Belt Velocity
FPM

The Limits of Belts

While gearboxes are rigid, belts rely on friction (or teeth, in the case of timing belts). This makes them excellent for absorbing shock loads, but limits their power transmission capabilities at extremes.

Belt Velocity Limits

If belt velocity (Feet Per Minute) gets too high, centrifugal force pushes the belt away from the sheave, drastically reducing friction and power transmission.

  • Standard V-Belts: Maximize efficiency around 4,000 FPM. Above 6,000 FPM, they risk flying off the sheaves or disintegrating due to centrifugal forces.
  • Dynamic Balancing: If your sheave is running above 5,000 FPM, it generally requires dynamic two-plane balancing, not just static balancing.

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