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Belt & Pulley Drive

Ratio = D₂/D₁; output rpm = n₁·D₁/D₂; open-belt length L = 2C + π(D₁+D₂)/2 + (D₂−D₁)²/4C. Units: mm, rpm; belt speed in m/min.

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Driver Ø D₁ (mm)

Driven Ø D₂ (mm)

Driver speed n₁ (rpm)

Center distance C (mm)

Ratio

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Output rpm

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Belt speed

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Belt length

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Open-belt geometry (no slip). A helper, not a substitute for engineering judgment.