1. What is Brushless Motor RPM?

Brushless motor RPM (Revolutions Per Minute) is the rotational speed of the motor shaft. It's determined by the input voltage, motor's Kv rating (RPM per volt), and any gear reduction applied.

2. How Does the Calculator Work?

The calculator uses the brushless motor RPM formula:

Where:

• \( Voltage \) — Input voltage to the motor (V)
• \( Kv \) — Motor velocity constant (RPM per volt)
• \( Gear\ Ratio \) — Ratio of motor speed to output speed (e.g., 3:1 would be entered as 3)

Explanation: The Kv rating indicates how many RPM the motor will turn per volt with no load. The actual RPM under load will be lower due to efficiency losses.

3. Importance of RPM Calculation

Details: Knowing the expected RPM helps in selecting the right motor and gearing for your application, whether it's for drones, RC vehicles, or other projects requiring precise speed control.

4. Using the Calculator

Tips: Enter the battery voltage (under load if known), the motor's Kv rating (found in motor specifications), and the gear ratio (enter 1 for direct drive). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is Kv in brushless motors?
A: Kv is the motor velocity constant representing RPM per volt with no load. A 1000Kv motor would theoretically spin at 1000 RPM with 1V applied.

Q2: Why is actual RPM lower than calculated?
A: Real-world factors like voltage drop under load, motor efficiency, and friction reduce the actual RPM below the theoretical value.

Q3: How does gear ratio affect RPM?
A: A higher gear ratio (e.g., 3:1) reduces output RPM by that factor while increasing torque. A lower ratio increases RPM but reduces torque.

Q4: What's a typical Kv range for brushless motors?
A: Kv ranges vary by application: 100-500 for large multicopters, 500-1500 for cars/trucks, 2000+ for small drones and high-speed applications.

Q5: Can I use this for brushed motors?
A: No, brushed motors have different characteristics. This calculator is specifically for brushless motors.