Electric Motor Speed Calculator

Synchronous Speed Formula:

\[ RPM = \frac{120 \times Frequency}{Poles} \]

Synchronous Speed:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Synchronous Speed?

Synchronous speed is the theoretical speed at which the magnetic field rotates in an AC induction motor. It represents the maximum possible speed the motor can achieve under ideal conditions without slip.

2. How Does the Calculator Work?

The calculator uses the synchronous speed formula:

\[ RPM = \frac{120 \times Frequency}{Poles} \]

Where:

\( RPM \) — Revolutions per minute (motor speed)
\( Frequency \) — AC power supply frequency in Hertz
\( Poles \) — Number of magnetic poles in the motor (always even number)

Explanation: The formula calculates the rotational speed of the magnetic field in an AC induction motor based on the electrical frequency and number of poles.

3. Importance of Synchronous Speed Calculation

Details: Understanding synchronous speed is crucial for motor selection, system design, and predicting motor performance in various applications from industrial machinery to household appliances.

4. Using the Calculator

Tips: Enter frequency in Hz (typically 50 or 60 Hz), and number of poles (must be even number, typically 2, 4, 6, or 8). All values must be valid (frequency > 0, poles ≥ 2 and even).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between synchronous speed and actual speed?
A: Actual speed is always slightly less than synchronous speed due to slip, which is necessary for torque production in induction motors.

Q2: Why must the number of poles be even?
A: Poles always come in pairs (north and south) in electric motors, so the total number must be even for proper magnetic field formation.

Q3: What are typical frequency values?
A: 50 Hz in most countries, 60 Hz in North America and some other regions. Some industrial applications use other frequencies.

Q4: How does pole number affect motor speed?
A: More poles result in slower synchronous speed. A 2-pole motor runs faster than a 4-pole motor at the same frequency.

Q5: Can this calculator be used for synchronous motors?
A: Yes, synchronous motors actually run at synchronous speed, while induction motors run slightly slower due to slip.