Calculate drive pull from carry/return resistance and the whole moving belt mass. Optionally check flat-belt drum traction, maximum tension and load slip.
Inputs, outputs and applicability
Inputs
- Carrying-run support
- Total product mass m on the carrying run
- Whole-loop belt mass mb, carrying plus return runs
- Effective drive drum diameter D
- Belt speed v in the positive direction
- Acceleration a (negative for deceleration)
- Conveying slope θ (negative downhill)
- Kinetic friction μb between belt underside and slider bed (example)
- Equivalent carrying-run resistance coefficient cc (example)
- Equivalent return-run resistance coefficient cr (example)
- Additional running resistance F₀ excluded above (example)
- Free drum/idler inertia Jf referred to the drive drum (example)
- Driven-drum-side rotating inertia Jd (example)
- Reduction i = motor speed / drive speed
- Forward-drive efficiency η
- Applicable motor-shaft torque limit Tlim at this speed/direction (example)
- Check tension, drum traction and product slip
- Operating low-side tension Tl, not initial pretension (example)
- Static friction μd between belt and drum (example)
- Drive-drum wrap angle β
- Applicable allowable total belt/joint tension Tb (example)
- Static friction μt between product and belt top (example)
Results
- Required motor-shaft torque Tm (negative means braking) (N·m)
- Drive pull Fu transmitted by the drum to the belt (signed) (N)
- Drive-drum shaft torque Td including inertia (N·m)
- Drive drum speed nd (rpm)
- Motor speed nm (rpm)
- Required forward-drive motor input power (W)
- Lossless braking power to absorb (W)
- Carry + return + additional running resistance (N)
- Carrying-run resistance (N)
- Return-run resistance (N)
- Entered torque limit / absolute required torque (—)
- Required high-side tension Th (N)
- Theoretical minimum low-side tension for drum traction (N)
- Available drum traction / absolute drive pull (—)
- Entered total tension allowable / required high-side tension (—)
- Contact force from belt to product (signed) (N)
- Product traction limit / absolute required product contact force (—)
Nc=(m+mb/2)g cosθ; Nr=(mb/2)g cosθ; Rc=μbNc or ccNc; Rr=crNr; Fu=(m+mb)a+mg sinθ+Rc+Rr+F₀+Jf a/r²; Td=Fu r+Jd a/r; ωd=v/r; Tm=Td/(iη) if Td≥0, otherwise Td/i. Th=Tl+|Fu|; Tl,min=|Fu|/[exp(μdβ)−1]; Fproduct=m(a+g sinθ).
Basic flat-belt model with equal carrying/return lengths, splitting total belt mass equally. Positive travel, v≥0 and |θ|≤60°. Includes acceleration of the whole belt; its closed-loop gravity terms cancel, so only products contribute net gravity lift. Underside μb and product-top μt describe different contacts. Roller-bed cc and return cr are equivalent coefficients based on the stated normal loads; add excluded roller weight/bearing/flexure/skirt resistance in F₀ without double counting. Jf covers free drums/idlers, and Jd covers driven-drum-side rotating bodies, each referred by summing Jj(ωj/ωd)². Exclude translating belt mass and motor rotor inertia. Free-body acceleration enters Fu; driven-side inertia adds shaft torque only. Capstan traction applies to flat-belt tension difference, not toothed-belt tooth skip or chains. Enter operating low-side Tl separately; initial-pretension redistribution/take-up is not solved. β is converted to radians. Tb must apply to the full width, joint, temperature and speed. Product slip is an aggregate along-route check; tipping, tracking and lateral slip are separate. Excludes breakaway friction, accumulation, curves, belt sag, transient tension, shaft loads, structural checks, RMS/thermal duty and life. Braking uses lossless reverse conversion, not a stop/regeneration approval.