1. What is Motor Sizing?

Motor sizing is the process of determining the appropriate power rating for an electric motor based on the torque and speed requirements of the application. Proper sizing ensures efficient operation and prevents motor failure.

2. How Does the Calculator Work?

The calculator uses the power calculation formula:

Where:

• \( P \) — Power in kilowatts (kW)
• \( T \) — Torque in Newton-meters (Nm)
• \( \omega \) — Rotational speed in revolutions per minute (RPM)
• 9.5488 — Conversion factor (30/π)

Explanation: The formula converts torque and rotational speed into mechanical power, accounting for unit conversions.

3. Importance of Proper Motor Sizing

Details: Correct motor sizing is critical for energy efficiency, operational reliability, and preventing premature motor failure. Oversized motors waste energy, while undersized motors may overheat.

4. Using the Calculator

Tips: Enter torque in Nm and rotational speed in RPM. The calculator will determine the required motor power in kW. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What safety factor should I use?
A: Typically 10-20% additional power is recommended to account for load variations and ensure reliable operation.

Q2: How does this differ for AC vs DC motors?
A: The power calculation is the same, but selection criteria may differ based on motor type and application requirements.

Q3: What if I have intermittent duty cycles?
A: For intermittent operation, you may be able to use a smaller motor than calculated, but consult manufacturer specifications.

Q4: Should I consider efficiency in my calculations?
A: This calculator gives mechanical power required. Divide by motor efficiency (typically 0.8-0.95) to get electrical input power.

Q5: How does temperature affect motor sizing?
A: High ambient temperatures may require derating (selecting a larger motor) to account for reduced cooling capacity.