1. What is the kV to RPM Equation?

The kV to RPM equation calculates the rotational speed of an electric motor based on its kV rating and the applied voltage. The kV rating represents the motor's RPM per volt with no load.

2. How Does the Calculator Work?

The calculator uses the simple equation:

Where:

• \( kV \) — Motor's kV rating (RPM per volt)
• \( V \) — Applied voltage (volts)

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 expected RPM helps in selecting the right motor and propeller combination for drones, RC vehicles, and other electric motor applications.

4. Using the Calculator

Tips: Enter the motor's kV rating (found in its specifications) and the voltage you plan to apply. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Is this the actual RPM under load?
A: No, this calculates the theoretical no-load RPM. Actual RPM under load will be lower due to factors like propeller load and efficiency losses.

Q2: What affects a motor's kV rating?
A: The kV rating is determined by the motor's design - number of windings, magnet strength, and other internal characteristics.

Q3: Can I use this for brushless and brushed motors?
A: Yes, the equation applies to both, though brushless motors are more commonly rated with kV values.

Q4: Why is my actual RPM lower than calculated?
A: Voltage drop in wires/battery, motor efficiency, and load (like a propeller) all reduce actual RPM below the theoretical value.

Q5: How does battery cell count relate to this?
A: Each LiPo cell provides about 3.7V nominal (4.2V fully charged). Multiply by cell count to get total voltage for the calculation.