1. What is the Motor Speed Equation?

The motor speed equation calculates the rotational speed of an AC induction motor based on the frequency of the power supply and the number of magnetic poles in the motor. This fundamental relationship helps in motor selection and performance analysis.

2. How Does the Calculator Work?

The calculator uses the motor speed equation:

Where:

• \( Speed \) — Rotational speed in revolutions per minute (rpm)
• \( f \) — Frequency of the power supply in Hertz (Hz)
• \( p \) — Number of magnetic poles in the motor

Explanation: The equation shows that motor speed is directly proportional to frequency and inversely proportional to the number of poles.

3. Importance of Motor Speed Calculation

Details: Knowing the synchronous speed of a motor is essential for proper motor selection, performance prediction, and troubleshooting in industrial applications.

4. Using the Calculator

Tips: Enter frequency in Hz and number of poles (must be even number). Standard frequencies are 50Hz or 60Hz, and poles typically range from 2 to 12.

5. Frequently Asked Questions (FAQ)

Q1: Why is the number 120 used in the equation?
A: The factor 120 comes from converting seconds to minutes (60) and accounting for the fact that each AC cycle produces two poles (60 × 2 = 120).

Q2: What is synchronous speed vs actual speed?
A: Synchronous speed is theoretical, while actual speed is slightly less due to slip in induction motors.

Q3: Can this be used for DC motors?
A: No, this equation is specific to AC induction motors. DC motor speed depends on voltage and load.

Q4: What are typical pole numbers?
A: Common pole numbers are 2, 4, 6, 8, etc. More poles mean lower speed but higher torque.

Q5: How does variable frequency affect speed?
A: Variable frequency drives can control motor speed by changing the input frequency proportionally.