1. What is the RPM Of Motor Formula?

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

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

2. How Does the Formula Work?

The formula used is:

Where:

• \( RPM \) — Revolutions per minute (motor speed)
• \( f \) — Electrical frequency (Hz)
• \( P \) — Number of magnetic poles (must be even number)

Explanation: The 120 factor converts from Hz to minutes (60 seconds × 2 poles per cycle). The speed is inversely proportional to the number of poles.

3. Importance of RPM Calculation

Details: Knowing a motor's RPM is crucial for proper equipment selection, speed matching, and performance analysis in industrial applications.

4. Using the Calculator

Tips: Enter the electrical frequency (typically 50 or 60 Hz) and the number of poles (even number, usually between 2-12). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the number of poles always even?
A: AC motors require pairs of north and south magnetic poles, so the count must be even.

Q2: What's a typical frequency value?
A: 50 Hz in most countries, 60 Hz in North America and some other regions.

Q3: Does this calculate synchronous or actual RPM?
A: This gives synchronous speed. Actual RPM is slightly less due to slip (typically 2-5% less).

Q4: How does voltage affect RPM?
A: Voltage doesn't affect synchronous speed, but insufficient voltage may prevent reaching full speed.

Q5: What's the RPM for a 4-pole motor at 60Hz?
A: 1800 RPM (synchronous speed), with actual speed around 1725-1750 RPM.