Quick Sheave & RPM Calculator
Drive relationship
N₁ × d ≈ N₂ × D
The calculator estimates driven RPM, drive ratio, and belt velocity.
Calculated speed is theoretical. Effective pitch diameter, belt creep, groove wear, and field conditions can affect actual RPM.
Belt pathSheavesDriver contact arcDriven contact arc
Interactive figure: Change the values at right. The sheaves, belt path, center distance and both wrap/contact arcs redraw automatically.
Change the Drive
Watch the wrap: Increase the driven sheave diameter or shorten the center distance. The amber driver contact arc becomes shorter while the blue driven contact arc becomes longer.
1 — FIELD INFORMATION
The service-factor menu is retained from the prototype and should be verified against the applicable service-factor selection logic before public release.
2 — DRIVE REQUIREMENT
Required Ratio
Motor
Design HP
Target Speed
3 — RECOMMENDED DRIVE & BELT SELECTION
| Section | Driver | Driven | Actual RPM | Belt Speed | Wrap | Nominal HP/Belt | K1 | K2 | Corrected HP/Belt | Belts |
|---|
4 — SELECTED DRIVE GEOMETRY
5 — BELT & INSTALLATION INFORMATION
6 — ENGINEERING BASIS / WHERE THE RESULT COMES FROM
Preliminary engineering selection — verify before installation.
This calculator uses the nominal V-belt horsepower relationships and Table 17-9 data from Shigley & Mischke, Mechanical Engineering Design, 5th Edition, together with the prototype contact-angle correction K1 and belt-length correction K2 logic previously developed for this M&RGC tool. Final belt products, ratings, dimensions, materials, tension and supplier recommendations must be verified with current manufacturer data.
This calculator uses the nominal V-belt horsepower relationships and Table 17-9 data from Shigley & Mischke, Mechanical Engineering Design, 5th Edition, together with the prototype contact-angle correction K1 and belt-length correction K2 logic previously developed for this M&RGC tool. Final belt products, ratings, dimensions, materials, tension and supplier recommendations must be verified with current manufacturer data.
WHY THIS SELECTION? — Show calculations
Field RPM Verification
A difference is a clue—not automatically “slip.”
Possible causes include belt creep/slip, worn grooves, effective diameter, alignment, variable-pitch sheaves, or RPM measurement.
Observe → Measure → Isolate → Verify → Correct → Test
Belt Installation & Tensioning
1. De-energize and secure
Follow applicable lockout/tagout procedures before inspection or adjustment.
2. Inspect the complete drive
Check grooves, shafts, bearings, keys, guards, belts, and driven equipment.
3. Install the correct matched set
Do not pry belts over sheave flanges.
4. Align the sheaves
Check parallel/offset and angular alignment.
5. Measure tension
Use the current belt manufacturer's specified method and values.
6. Run-in and recheck
Secure the equipment again before rechecking tension.
Deflection-Force Worksheet
Never measure or adjust belt tension on moving equipment.