1. What is the Motor RPM Formula?

Definition: This calculator determines the rotational speed (RPM) of an AC motor based on the electrical frequency and number of pole pairs.

Purpose: It helps electrical engineers and technicians understand and predict motor performance characteristics.

2. How Does the Formula Work?

The calculator uses the formula:

Where:

• \( RPM \) — Revolutions per minute
• \( f \) — Electrical frequency (Hz)
• \( P_p \) — Number of pole pairs

Explanation: The frequency (Hz) is multiplied by 60 to convert to minutes, then divided by the number of pole pairs to determine RPM.

3. Importance of Motor RPM Calculation

Details: Knowing the motor RPM is crucial for proper equipment selection, speed matching, and performance optimization in industrial applications.

4. Using the Calculator

Tips: Enter the electrical frequency in Hz and the number of pole pairs (not total poles). For example, a 4-pole motor has 2 pole pairs.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between poles and pole pairs?
A: A pole pair consists of one north and one south magnetic pole. Total poles = 2 × pole pairs.

Q2: What frequency should I use?
A: Standard power frequencies are 50Hz (Europe/Asia) or 60Hz (North America).

Q3: Why multiply by 60 in the formula?
A: Frequency is in cycles per second (Hz), and we convert to minutes (×60) to get RPM.

Q4: What's the RPM for a 4-pole motor at 60Hz?
A: 1800 RPM (2 pole pairs × 60Hz × 60 ÷ 2 = 1800).

Q5: Does this work for synchronous and induction motors?
A: This calculates synchronous speed. Induction motors run slightly slower due to slip.