Electric Motors
Motor Torque Calculator
Use Motor Torque Calculator to calculate shaft torque from shaft power and speed. Keep the entered conditions with the answer so later comparisons are fair.
Model Motor Torque
The defaults only show how Motor Torque works; replace them with values for the actual equipment or period.
The Motor Torque equation
Read the Motor Torque equation from the units on this page. A familiar symbol can shift meaning between DC, AC, energy, component, or billing work.
A clean Motor Torque result confirms the arithmetic for shaft torque; it does not prove the equipment rating or source data is the right one.
Only the entries shown on Motor Torque feed shaft torque. If another correction factor matters, keep it in the notes or make a separate run.
Sample Motor Torque run
Using the sample values, Shaft power = 7.5 kW; Speed = 1450 rpm, the primary result is 49.40 N·m.
This Motor Torque one-input test is a scale check, showing direction and sensitivity without turning the changed case into a recommendation.
If the changed shaft power comes from a real measurement, keep the original Motor Torque run so the source of the difference remains clear.
Source notes for Motor Torque
Treat the Motor Torque input panel like a short measurement log. If shaft power is assumed rather than measured, label it before copying shaft torque.
| Entry | Example | Check before use |
|---|---|---|
| Shaft power | 7.5 kW | Enter shaft power in kW. |
| Speed | 1450 rpm | Enter speed in rpm. |
Use Motor Poles Frequency for that neighboring calculation rather than adding unstated assumptions here.
What not to assume from Motor Torque
This is average steady shaft torque.
- Mechanical load profile
- Service factor
- Starting current
When shaft torque is close to a rating, use the stricter review path instead of relying on the extra decimals shown by Motor Torque.
When your notes point to VFD Motor Speed, open it after saving this baseline so the two cases do not get mixed.
Reading shaft torque
If shaft torque is near a limit, preserve the calculated value from Motor Torque and apply required margin after the calculation.
Keep Motor Torque tied to the motor nameplate, supply system, duty cycle, and starting condition.
Audit trail for shaft torque
Record the motor nameplate, supply voltage, enclosure, duty, and whether Motor Torque describes running or starting.
If a later Motor Torque run changes only shaft power, label it as sensitivity work. Several changed conditions deserve a new baseline.
If the next step shifts toward Motor Slip, keep that as a separate worksheet instead of forcing the numbers into Motor Torque.