1. What is Synchronous Speed?

Synchronous speed is the speed of the rotating magnetic field in the stator of a synchronous motor. It depends on the frequency of the power supply and the number of poles in the motor.

2. How Does the Calculator Work?

The calculator uses the synchronous speed formula:

Where:

• \( N_s \) — Synchronous speed in RPM (revolutions per minute)
• \( f \) — Frequency of the power supply in Hz
• \( p \) — Number of poles in the motor (always an even number)

Explanation: The factor 120 comes from converting seconds to minutes (60) and accounting for the fact that each pair of poles creates one complete cycle (2).

3. Importance of Synchronous Speed Calculation

Details: Knowing the synchronous speed is essential for motor selection, speed control, and understanding motor performance characteristics. In synchronous motors, the rotor turns at exactly the synchronous speed.

4. Using the Calculator

Tips: Enter the power supply frequency in Hz and the number of poles in the motor. The number of poles must be an even number (2, 4, 6, etc.).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between synchronous and asynchronous motors?
A: Synchronous motors rotate at synchronous speed, while asynchronous (induction) motors rotate slightly slower due to slip.

Q2: Why must the number of poles be even?
A: Magnetic poles always come in pairs (north and south), so the total number must be even.

Q3: What are typical synchronous speeds?
A: For 60Hz systems: 3600 RPM (2-pole), 1800 RPM (4-pole), 1200 RPM (6-pole). For 50Hz systems: 3000 RPM, 1500 RPM, 1000 RPM respectively.

Q4: Can synchronous motors operate at other speeds?
A: True synchronous motors only operate at synchronous speed. Variable speed operation requires variable frequency drives.

Q5: How does load affect synchronous motor speed?
A: Synchronous motors maintain constant speed regardless of load, up to their maximum torque capability.