Examples
Examples
Try the starting example
- Pulley 1 pitch radius (mm)
- 50
- Pulley 2 pitch radius (mm)
- 100
- Pulley 1 center x (mm)
- 0
- Pulley 1 center y (mm)
- 0
- Pulley 2 center x (mm)
- 300
- Pulley 2 center y (mm)
- 0
- Center distance (mm)
- 300
- Exact ideal open-belt pitch length (mm)
- 1,079.591684
- Smaller-pulley wrap (degrees)
- 160.811864
- Larger-pulley wrap (degrees)
- 199.188136
Try another scenario
- Pulley 1 pitch radius (mm)
- 50
- Pulley 2 pitch radius (mm)
- 100
- Pulley 1 center x (mm)
- 0
- Pulley 1 center y (mm)
- 0
- Pulley 2 center x (mm)
- 400
- Pulley 2 center y (mm)
- 0
- Center distance (mm)
- 400
- Exact ideal open-belt pitch length (mm)
- 1,277.497074
- Smaller-pulley wrap (degrees)
- 165.638488
- Larger-pulley wrap (degrees)
- 194.361512
Calculation method
Calculation method
Center distance (mm)
C=hypot(x2-x1,y2-y1).
Exact ideal open-belt pitch length (mm)
2*sqrt(C²-(R-r)²)+pi*(R+r)+2*(R-r)*asin((R-r)/C).
Smaller-pulley wrap (degrees)
180-2*asin((R-r)/C)*180/pi.
Larger-pulley wrap (degrees)
180+2*asin((R-r)/C)*180/pi.
Symbols and units
- a
- Pulley 1 pitch radius (mm)
- b
- Pulley 2 pitch radius (mm)
- c
- Pulley 1 center x (mm)
- d
- Pulley 1 center y (mm)
- e
- Pulley 2 center x (mm)
- f
- Pulley 2 center y (mm)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- Supported routing is one open, uncrossed belt around two external circular pulleys in a plane. Pitch radii supplied; no multi-pulley serpentine routing, tension, stretch, teeth, flange or manufacturer belt selection. Supported limits: Radii>0; center distance>sum(radii) (nonintersecting pulleys); finite coordinates.
Are these inputs private?
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