Slack-side and take-up tension
Traction and sag require absolute belt tensions, not only effective difference.
Engineering
Conveyor Load Calculator
Calculate material and moving line load, running resistance, lift force, effective and starting tension, drive power, and pulley torque for a belt conveyor screen.
BELT CONVEYOR LOAD
Translate throughput and speed into kilograms per metre before calculating drive demand
Throughput becomes a belt load only after belt speed is known. This calculator derives material kilograms per metre, adds belt mass, estimates running and lift forces, applies a starting factor, and converts effective tension into power and pulley torque. The ledger exposes every force component and does not claim to reproduce a full conveyor tension analysis.
Material line load (kg/m)—
Material on loaded length (kg)—
Running effective tension (N)—
Starting effective tension (N)—
Running belt power (kW)—
Drive pulley torque (N*m)—
BELT CONVEYOR LOAD
Conveyor line-load and tension ledger
Use the component forces to identify whether throughput, belt mass, route, lift, or assumed resistance governs. A starting factor is not a dynamic model and must not be used to select belt rating or drive hardware without the applicable method.
| Load component | Flow or coefficient | Speed or geometry | Calculated result | Unit or meaning |
|---|
CURRENT CALCULATION PROCESS
Formula, substitution, intermediate values, and reconciliation
qmaterial = mdot/v; Frr = f(qmaterial+qbelt)gL; Flift = (mdot/v)gH; Te = Frr+Flift; P=Te v; Tpulley=Te D/2
The model separates material line load, belt mass resistance, and elevation force. The same effective tension produces both running power and pulley torque; a separate factor scales it for a start screen.
| Input / symbol | Engineering meaning and unit | Current value |
|---|---|---|
| massFlowTph | Material flow (t/h) — Steady throughput | 500 |
| beltSpeed | Belt speed (m/s) — Actual or proposed operating speed | 2.8 |
| beltMassKgM | Belt mass (kg/m) — Mass per one metre of belt length on the modeled basis | 22 |
| conveyorLengthM | Conveyor length (m) — Carrying path used in resistance screen | 220 |
| liftM | Vertical lift (m) — Positive uphill; negative downhill | 28 |
| resistanceCoefficient | Running resistance coefficient — Planning coefficient for moving line mass | 0.03 |
| drivePulleyDiameterM | Drive pulley diameter (m) — Pitch diameter for torque screen | 0.8 |
| startFactor | Starting tension factor — Entered multiplier on running effective tension | 1.45 |
Intermediate values remain unrounded until display formatting.
HOW TO USE THIS MODEL
Create one named running or starting load case
- Enter throughput and belt speed from the same operating case.
- Enter belt mass on a clearly stated single-length or system basis consistent with the resistance model.
- Enter carrying length, signed lift, and a documented planning resistance coefficient.
- Use pulley pitch diameter and a starting factor that matches the intended screen.
- Review line load, effective tension, power, and torque, then complete detailed resistance and dynamic tension analysis.
BELT CONVEYOR LOAD FUNDAMENTALS
Load quantities behind conveyor drive demand
- Material line load
- Material mass per metre, equal to mass flow divided by belt speed.
- Belt line mass
- Belt mass represented per metre in the chosen resistance model.
- Running resistance
- Force required to overcome rolling, flexure, indentation, alignment, skirt, and other effects.
- Lift force
- Force component associated with changing material elevation.
- Effective tension
- Difference in belt tensions providing useful drive force at the pulley.
- Pulley torque
- Effective tension multiplied by pulley pitch radius.
MODEL AND FORMULA
Preserve the force chain from throughput to torque
qmaterial = mdot/v; Frr = f(qmaterial+qbelt)gL; Flift = (mdot/v)gH; Te = Frr+Flift; P=Te v; Tpulley=Te D/2
The model separates material line load, belt mass resistance, and elevation force. The same effective tension produces both running power and pulley torque; a separate factor scales it for a start screen.
DEEPER ENGINEERING ANALYSIS
Why detailed belt tensions require more than effective tension
Starting dynamics
Acceleration, drive control, take-up response, belt elasticity, and material motion can create transient peaks.
Downhill regeneration
A sufficiently negative lift can drive the belt; braking, regeneration, rollback, and emergency stopping then govern.
WORKED DECISION CASES
Two load cases with different concerns
Uphill mineral conveyor
Lift force dominates running demand, so pulley torque and brake or restart requirements receive special review.
Long horizontal conveyor
Material lift is zero, but accumulated idler and belt resistance governs; alignment and maintenance evidence become critical.
TECHNICAL LANGUAGE
Conveyor load glossary
- Effective tension
- Tight-side minus slack-side belt tension associated with drive force.
- Tight side
- Higher-tension belt span at the drive pulley.
- Slack side
- Lower-tension belt span at the drive pulley.
- Traction
- Frictional ability of pulley lagging and belt to transmit tension ratio without slip.
- Belt sag
- Vertical deflection between idlers affected by load and tension.
- Regenerative conveyor
- Downhill conveyor capable of returning power to the drive system.
EVIDENCE AND DATA LINEAGE
Retain one synchronized flow, speed, and route case
Keep throughput and belt-speed records, material and belt mass basis, route length and elevation survey, resistance source, pulley pitch diameter, starting method, drive control, take-up arrangement, unrounded force ledger, and detailed tension-model revision.
LIMITS AND EXCLUSIONS
What the load screen excludes
- No detailed conveyor resistances, absolute tight/slack tensions, pulley traction, belt sag, rating, take-up, or transition analysis is included.
- No acceleration, VFD torque, flywheel, brake, rollback, emergency-stop, or regenerative transient is modeled.
- No pulley, shaft, bearing, idler, structure, foundation, chute, guarding, fire, dust, or electrical safety design is established.
RELIABLE SOURCES
References for this page's method and boundaries
FREQUENTLY ASKED QUESTIONS
Questions about conveyor load and tension
Why does line load decrease when speed increases?
At fixed mass flow, faster belt moves the same tonnes with fewer kilograms on each metre.
Does lower line load mean higher speed is always better?
No. Dust, impact, wear, spillage, chute behavior, power, and safety can worsen.
Is belt mass counted once or twice?
Use a mass basis consistent with the chosen resistance model; this simplified input must be documented.
Can lift be negative?
Yes, but a strongly downhill case may become regenerative and requires a dedicated brake and dynamic analysis.
Does starting factor select motor size?
No. It is a screening multiplier, not a motor torque-speed, VFD, or transient conveyor model.
Can pulley torque size the shaft?
Not alone. Service factors, transient torque, pulley assembly, shaft bending, fatigue, keying, and bearings remain.
RELATED CALCULATORS
Continue the engineering review
Use these follow-on models to test a different boundary without hiding it inside this calculation.
IMPORTANT ENGINEERING NOTE
Do not select belt or drive hardware from the screening tension alone
Final selection requires the governing conveyor method, all resistance and load cases, absolute and transient belt tensions, drive and brake behavior, mechanical and structural capacity, material handling and guarding design, and qualified approval.