Motor Rated Torque
Based on T = 9550 P/n: torque from power & speed, power from torque & speed, speed from power & torque.
Inputs
Formula
T = 9550 P / n (P:kW, n:rpm, T:N·m)
Fundamentals
Motor torque shows its ability to drive a load in rotation — a key selection metric.
Torque–power: $T=9550\,P/n$ ($P$ kW, $n$ r/min, result N·m); or $T=P_\text{em}/\omega$ from electromagnetic power.
History
The motor torque-speed characteristic came from DC-motor (19th c.) and induction-motor (Tesla, 1887) theory.
Engineering applications
Used to match starting/running torque and check overload for hoists, conveyors and machine tools.
Glossary
| Torque $T$ | Rotational driving moment (N·m). |
| Power $P$ | Mechanical output (kW). |
| Speed $n$ | Revolutions per minute (r/min). |
How to use
- Fill in Power P, Speed n, Torque T in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Torque T, Power P, Speed n in the results area.
Formula notesMotor rated torque T = 9550·P/n (P kW, n r/min).
Formula · Worked Example · Knowledge
Formula
Rated torque $T=9550P/n$ (P kW, n rpm, T N·m); reverse for power or speed.
Worked Example
P=15 kW, n=1500 → T=95.5 N·m; with T=100 → P=15.7 kW.
Key Points
- In the constant-power range, higher speed → lower torque.
- Starting torque often exceeds rated.
- Induction motors have a pull-out (max) torque.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Power P (kW) | P | kW | 15 |
| Speed n (rpm) | n | rpm | 1500 |
| Torque T (N·m) | T | N·m | 0 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Torque T | T | N·m |
| Power P | P | kW |
| Speed n | n | rpm |
Applications
- Common engineering use cases
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: T = 9550 P / n (P:kW, n:rpm, T:N·m)
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Common engineering use cases