Motor Sizing Calculator
Accurate motor sizing calculations for various applications
Motor Sizing Calculator
Compliant with IEC 60034 Standards
Recommended Motor Parameters:
Continuous Power (kW): 0.00
Acceleration Torque (Nm): 0.00
Total Peak Torque (Nm): 0.00
How to Use the Motor Sizing Calculator
Input Required Torque
- Enter the continuous torque required by your application in Newton-meters (Nm).
- This is the torque needed to overcome friction and external loads.
Input Operating Speed
- Provide the desired operating speed of the motor in Revolutions Per Minute (RPM).
- This is the speed at which the motor will run during normal operation.
Input Acceleration & Inertia
- Enter the desired acceleration time in seconds.
- Input the total load inertia in kilogram-meter squared (kg.m²).
- These values are crucial for calculating peak torque during acceleration.
Motor Sizing Fundamentals
Key Factors
For successful motor sizing, three important factors must be determined: torque, inertia, and speed.
- Torque: The rotational force required to move the load.
- Inertia: The resistance of an object to changes in its state of motion.
- Speed: The rotational velocity at which the motor operates.
Step-by-Step Calculation
The motor sizing starts with a first-pass estimation of all loading and a simple move profile defining the worst-case acceleration and velocity requirements. This process follows the Laws of Motion by Newton.
- Define/calculate the key aspects of the motion profile required.
- Calculate/estimate all of the torque loadings in the system.
- Estimate any additional torque required due to the environment or the system dynamics.
- Check your results against an initial motor selection that fits within your desired size and physical constraints.
- Factor in the motor itself to the system and repeat step 4 if necessary.
- Check the electrical input power requirements to see that they align with what’s available.
Key Factors & Formulas
Continuous Power (kW):
P_cont = (T_req × N × 2π) / (60 × 1000)
Acceleration Torque (Nm):
T_accel = (J_load × N × 2π) / (60 × t_accel)
Total Peak Torque (Nm):
T_peak = T_req + T_accel
Where: T_req = Required Torque (Nm), N = Operating Speed (RPM), J_load = Load Inertia (kg.m²), t_accel = Acceleration Time (s)
Example Calculation
Motor Sizing Example:
Required Torque: 10 Nm
Operating Speed: 1500 RPM
Acceleration Time: 0.5 s
Load Inertia: 0.01 kg.m²
P_cont = (10 × 1500 × 2π) / (60 × 1000) ≈ 1.57 kW
T_accel = (0.01 × 1500 × 2π) / (60 × 0.5) ≈ 3.14 Nm
T_peak = 10 + 3.14 = 13.14 Nm
Results: Continuous Power = 1.57 kW | Acceleration Torque = 3.14 Nm | Total Peak Torque = 13.14 Nm
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