Torque Speed Curve Calculator

Speed (RPM)	Torque (Nm)	Power (kW)
0	220.00	0.00
300	205.33	6.45
600	190.67	11.98
900	176.00	16.59
1200	161.33	20.27
1500	146.67	23.04
1800	132.00	24.88
2100	117.33	25.80
2400	102.67	25.80
2700	88.00	24.88
3000	73.33	23.04

Formula Used

Linear torque speed relation: T = T_stall × (1 − N / N_no-load)

Angular speed: ω = 2πN / 60

Mechanical power: P = T × ω

Slip percentage: Slip = ((N_no-load − N_operating) / N_no-load) × 100

Gear adjusted shaft torque: T_out = T × Gear Ratio

Gear adjusted shaft speed: N_out = N / Gear Ratio

This approach suits quick engineering estimation, motor comparison, and load matching studies. Real machines may show nonlinear regions near saturation or breakdown torque.

How to Use This Calculator

Enter stall torque from the machine datasheet.
Enter no load speed in RPM.
Set the intended operating speed.
Provide efficiency, gear ratio, and load torque.
Enter rated voltage and current for extra power context.
Select how many curve points you want plotted.
Press Generate Curve to see the results above the form.
Review torque margin, power, and shaft output values.
Use the export buttons to save a CSV or PDF summary.

FAQs

1. What does a torque speed curve show?

A torque speed curve shows how available torque changes as rotational speed increases. It helps engineers compare starting behavior, operating range, and load compatibility.

2. Why does torque usually fall as speed rises?

Many drive systems produce high starting torque and lower torque near no load speed. The simplified linear model captures that common trend for quick analysis.

3. What is stall torque?

Stall torque is the maximum torque available at zero speed. It marks the starting point of the curve and indicates the system’s launch capability.

4. What is no load speed?

No load speed is the maximum speed reached with minimal resisting torque. At this point, useful output torque approaches zero in the linear model.

5. Why is torque margin important?

Torque margin compares available torque against required load torque. A positive margin suggests safer operation, while a negative margin suggests overload risk.

6. How does gear ratio affect the output?

Gear reduction increases shaft torque and decreases shaft speed. This helps match a fast motor to a heavier load needing more turning force.

7. Is this calculator suitable for all motors?

This tool is best for preliminary estimates. Real torque speed behavior can differ for induction motors, DC motors, servos, and variable frequency drives.

8. Why export the results?

Exporting helps with reporting, comparison, recordkeeping, and design review. You can save the generated data for later analysis or documentation.