1. What is the Synchronous Motor Speed Formula?

The synchronous speed formula calculates the rotational speed of the magnetic field in a synchronous motor. It depends on the frequency of the AC power supply and the number of poles in the motor.

2. How Does the Calculator Work?

The calculator uses the synchronous speed equation:

Where:

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

Explanation: The 120 factor comes from converting seconds to minutes (60) and accounting for the fact that each AC cycle produces two poles (60×2=120).

3. Importance of Synchronous Speed Calculation

Details: Knowing the synchronous speed is essential for motor selection, speed control, and understanding motor performance characteristics.

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: Why is synchronous speed important?
A: It determines the motor's operating speed when synchronized with the AC frequency, crucial for applications requiring precise speed control.

Q2: What's the difference between synchronous and actual speed?
A: In synchronous motors, the rotor turns at exactly synchronous speed. In induction motors, there's a slight difference called slip.

Q3: How does frequency affect motor speed?
A: Higher frequency increases synchronous speed proportionally. This is how variable frequency drives control motor speed.

Q4: Why must pole number be even?
A: Magnetic poles always come in pairs (north and south), so the number must be even for proper magnetic field formation.

Q5: What are typical synchronous speeds?
A: For 60Hz systems: 3600 RPM (2-pole), 1800 RPM (4-pole), 1200 RPM (6-pole). For 50Hz: 3000 RPM, 1500 RPM, 1000 RPM respectively.