Motor sizing calculator

Choose the drive type, enter mass, dimensions, speed and acceleration time. The calculator gives the load torque including acceleration and friction, then the torque, speed and power at the motor shaft through the gearbox, for rotary tables, ball screw axes, belt conveyors and hoists.

What it calculates

• Rotary table / turntable: inertia, acceleration torque, friction torque
• Ball screw axis: horizontal or vertical, process force, screw pitch and efficiency
• Belt conveyor on a slope and hoist / winch
• Motor torque, speed and power through the gear ratio and gearbox efficiency, with service factor

Formulas

Rotary: J = m·r²/2,  α = ω/t_a,  T = J·α + T_f
Screw: F = m·g·μ (horizontal) or m·g (vertical) + F_proc + m·a
       T = F·P / (2π·η_s),  n = v / P
Belt:  F = m·g·(μ·cosθ + sinθ) + m·a,  T = F·D/2
Hoist: F = m·(g + a),  T = F·D/2
Motor: T_m = T / (i·η_g),  n_m = n·i,  P = T_m·2π·n_m / 60

Worked example

How to use it

1. Create a free account with Google or e-mail.
2. Open the calculator and enter your values; units can be metric or imperial.
3. Read the result with its formula and source, and export to PDF, DXF or CSV where available.

Frequently asked questions

How do I choose a motor for a conveyor?

Calculate the belt pull from friction, slope and acceleration, convert it to torque at the drum, then divide by the gear ratio and efficiency to get motor torque and power.

Why does acceleration matter?

During start-up the motor must overcome inertia as well as the steady load; short acceleration times can double the required torque.

What service factor should I use?

About 1.0–1.2 for smooth loads and 1.5 or more for shock loads or frequent starts.

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Results are engineering estimates for planning. They do not replace the applicable standard, a qualified procedure or a check by a qualified engineer.