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Motor Torque Calculator

AS/NZS 1359 + IEC 60034

Phase 3 Calculator

Inputs

Rated power of motor

Operating speed or synchronous speed

Mechanical load characteristic

Results

Full-Load Torque

49.39

N·m

Motor Typeinduction
Power (kW)7.5
Speed (RPM)1450
Starting Torque86.43 N·m
Breakdown Torque123.48 N·m
Power Factor at Load0.870
Pull-up Torque74.08 N·m
✅

Starting Torque Adequate for Load Type

175 %

✅

Breakdown Torque Margin

250 %

✅

Starting Method Compatible with Load

1 Pass/Fail

Important: These results are indicative only. Motor selection must be verified by a qualified electrical engineer in accordance with AS/NZS 1359 and manufacturer specifications before installation.

Motor Torque Calculation Guide — AS/NZS 1359 + IEC 60034

Motor torque is the rotational force produced by an electric motor. Accurate calculation is essential for selecting appropriately sized motors and verifying mechanical load compatibility. This calculator determines full-load torque, starting torque, and power relationships based on motor type, speed, starting method, and load characteristics.

Motor Types

  • Induction Motors: Most common type. Asynchronous operation with slip. Robust, low cost, suitable for constant load applications.
  • Synchronous Motors: Run at exactly line frequency. Used for power factor correction and constant speed requirements.
  • DC Motors: Precise speed control. Higher starting torque. Used in specialized applications.

Starting Methods

  • DOL (Direct On Line): Maximum starting torque. High inrush current. Suitable for light loads and small motors.
  • Star-Delta: Reduces starting current to 1/3 of DOL. Lower starting torque. Common for larger motors.
  • Soft Starter: Electronic current limiting. Smooth ramp-up. Reduces mechanical stress.
  • VFD (Variable Frequency Drive): Full speed control. Optimized starting profile. Most flexible option.

Load Types

  • Constant Torque: Load torque independent of speed (fans, compressors). Requires more power at higher speeds.
  • Variable Torque: Load torque varies with speed squared (centrifugal fans, pumps). Reduces power at lower speeds.
  • Constant Power: Load power independent of speed (hoisting, winding). Motor must handle high torque at low speed.

Disclaimer: These results are indicative only. Motor selection must be verified by a qualified electrical engineer in accordance with AS/NZS 1359 and equipment manufacturer specifications before installation. Mechanical load analysis and thermal derating are critical.