1. What is the BLDC RPM Equation?

The BLDC (Brushless DC) motor RPM equation calculates the rotational speed of a motor based on the input voltage and the motor's Kv rating. This provides a theoretical maximum speed under no-load conditions.

2. How Does the Calculator Work?

The calculator uses the BLDC RPM equation:

Where:

• \( V \) — Input voltage (volts)
• \( Kv \) — Motor velocity constant (RPM per volt)

Explanation: The equation shows the direct proportional relationship between voltage and RPM for a given motor Kv rating.

3. Importance of RPM Calculation

Details: Knowing the theoretical RPM helps in motor selection, propeller matching, and predicting performance in electrical applications like drones, RC vehicles, and industrial machinery.

4. Using the Calculator

Tips: Enter the input voltage in volts and the motor's Kv rating (found in motor specifications). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Is this the actual RPM under load?
A: No, this is the theoretical no-load RPM. Actual RPM under load will be lower due to factors like current draw, efficiency, and mechanical load.

Q2: What affects the actual RPM?
A: Load, battery condition, wiring resistance, ESC efficiency, temperature, and motor quality all affect real-world RPM.

Q3: How accurate is this calculation?
A: It's accurate for no-load conditions. For loaded conditions, multiply by estimated efficiency (typically 80-95% for quality motors).

Q4: What's a typical Kv range?
A: Small drone motors: 1000-3000 Kv, RC car motors: 2000-5000 Kv, industrial motors: often below 500 Kv.

Q5: Can I use this for brushed motors?
A: The basic principle is similar, but brushed motors typically have lower efficiency and different characteristics under load.