1. What is Shaft Speed?

Shaft speed, measured in revolutions per minute (rpm), is the rotational speed of an electric motor's shaft. It's determined by the frequency of the power supply and the number of magnetic poles in the motor.

2. How Does the Calculator Work?

The calculator uses the shaft speed formula:

Where:

• \( Speed \) — Shaft speed in revolutions per minute (rpm)
• \( Frequency \) — Power supply frequency in Hertz (Hz)
• \( Poles \) — Number of magnetic poles in the motor

Explanation: The formula calculates the synchronous speed of an AC motor, where 60 converts seconds to minutes.

3. Importance of Shaft Speed Calculation

Details: Knowing the shaft speed is essential for proper motor selection, system design, and ensuring compatibility with driven equipment.

4. Using the Calculator

Tips: Enter the power supply frequency in Hz and the number of poles in the motor. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is synchronous speed?
A: Synchronous speed is the theoretical speed at which the motor's magnetic field rotates, which is slightly higher than the actual shaft speed due to slip.

Q2: How do I determine the number of poles?
A: The number of poles is typically specified in the motor's documentation or nameplate. It's always an even number (2, 4, 6, etc.).

Q3: What's the difference between synchronous and actual speed?
A: Actual speed is slightly less than synchronous speed due to slip, which is necessary for torque production in induction motors.

Q4: Does this work for DC motors?
A: No, this formula is for AC motors only. DC motor speed depends on voltage and field current.

Q5: What are typical frequency values?
A: 50 Hz in most countries, 60 Hz in North America and some other regions.