1. What is VFD Hz to RPM Conversion?

The VFD (Variable Frequency Drive) Hz to RPM conversion calculates the rotational speed of an AC motor based on the frequency supplied by the VFD and the number of motor poles. This is essential for motor control and speed regulation in industrial applications.

2. How Does the Calculator Work?

The calculator uses the VFD Hz to RPM formula:

Where:

• \( RPM \) — Revolutions per minute (motor speed)
• \( Hz \) — Frequency in hertz (VFD output frequency)
• \( Poles \) — Number of motor poles (always even number)
• \( 60 \) — Conversion factor (seconds to minutes)

Explanation: The formula calculates the synchronous speed of an AC motor. The actual motor speed will be slightly less due to slip in induction motors.

3. Importance of RPM Calculation

Details: Accurate RPM calculation is crucial for proper motor sizing, speed control, process optimization, and preventing motor damage from overspeeding or underspeeding.

4. Using the Calculator

Tips: Enter frequency in 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 relationship between Hz and RPM?
A: RPM is directly proportional to frequency. Doubling the frequency doubles the motor speed, assuming constant number of poles.

Q2: Why do poles need to be even numbers?
A: AC motors are designed with even numbers of poles to create the rotating magnetic field necessary for operation.

Q3: What is synchronous speed vs actual speed?
A: Synchronous speed is the theoretical maximum, while actual speed is slightly less due to slip in induction motors (typically 2-5% less).

Q4: Can I use this for DC motors?
A: No, this formula is specific to AC motors controlled by VFDs. DC motors have different speed control characteristics.

Q5: What are common pole configurations?
A: Common configurations are 2-pole (high speed), 4-pole (standard), and 6-pole or 8-pole (low speed) motors.