Quickly size gate hoist motors using load, speed, and radius today accurately. Apply efficiency, gearing, and service factor to match real site conditions safely.
Enter your site values. Use allowances for friction, acceleration, and service factor to reflect real hoisting conditions.
Use these sample values to test outputs and confirm your units.
| Load | Speed | Friction | Efficiency | Gear Ratio | Service Factor | Drum Radius | Lift Height |
|---|---|---|---|---|---|---|---|
| 1200 kg | 0.12 m/s | 8% | 78% | 20 | 1.25 | 0.20 m | 3 m |
| 18 kN | 6 m/min | 12% | 75% | 30 | 1.35 | 0.25 m | 5 m |
The calculator estimates motor input power from the lifting force and speed:
F_load = m × g (or enter force directly in kN)F_total = F_load × (1 + f) + F_extra + m × aP_mech = F_total × vP_motor = (P_mech ÷ η_total) × SFT_drum = F_total × rrpm_drum = (v ÷ (2πr)) × 60rpm_motor = rpm_drum × gear_ratioWhere g is gravity, f is friction allowance, v is lifting speed, r is drum radius, η_total combines hoist and gearbox efficiencies, and SF is service factor.
Gate hoists in construction must lift reliably through variable friction, weather, and debris. This calculator converts your load and lifting speed into motor input power, then applies efficiencies and a service factor. The output supports early sizing, bid packages, and quick checks during commissioning when field conditions differ from drawings.
Record the total lifted load, including gate leaf, stem, lifting beam, and any attachments. Measure the intended lifting speed or cycle time, and confirm drum radius to the rope centerline. Note guide condition, seal drag, and any binding forces. Capture gearbox ratio and typical efficiency from the drive nameplate or vendor sheet.
The total lifting force combines the main load with friction allowance, extra force, and acceleration. Drum torque equals force times radius, so small radius changes can shift torque noticeably. If torque is high while power is moderate, the system may need a stronger gearbox or larger drum rather than a larger motor.
Mechanical power at the drum is force multiplied by speed. The motor input power increases when efficiencies drop, so conservative values are safer for dusty sites or older equipment. Service factor accounts for starts, stops, shock loads, and duty severity. A higher factor helps prevent overheating and nuisance trips during repeated lifts.
Using 1200 kg, 0.12 m/s, 8% friction, 78% hoist efficiency, 95% gearbox efficiency, 20:1 ratio, 0.20 m drum radius, and a 1.25 service factor produces a defensible motor rating estimate. After installation, compare actual current draw and lift time. If current is elevated, inspect alignment, lubrication, and guide wear before upsizing the motor. Document assumptions in your submittal and maintenance log.
Enter the total lifted load: gate leaf, stem, lifting beam, chains, and any attachments. If you only have force, switch to kN and enter it directly.
Use a realistic overall hoist efficiency that includes bearings, drum, and drivetrain losses. If unknown, start with 70–85% for mechanical systems and refine using vendor data or field measurements.
For light, occasional lifts, 1.10–1.20 is common. For frequent starts, shock loading, or harsh site conditions, 1.25–1.50 helps protect against overheating and trips.
Extra force covers non-ideal loads such as seal drag, debris binding, wind pressure, or icing. Estimate it conservatively from inspections or test pulls and add it in Newtons.
Torque equals force times radius. A larger radius raises required torque and affects drum rpm, which changes motor speed through the gear ratio. Measure to the rope or chain centerline.
It estimates lifting power. For lowering, consider braking, regeneration, and controlled descent requirements. Use the torque and speed outputs as a starting point, then confirm with the drive and brake manufacturer.
Verify units first. Then review friction allowance, extra force, and efficiencies. Inspect alignment, lubrication, guides, and seals. A binding gate can inflate force more than speed changes.
This tool provides an engineering estimate for motor sizing. For final selection, confirm duty class, braking method, thermal limits, and local safety requirements.
Accurate inputs create safer lifts and longer equipment life.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.