1. What is RPM from Voltage Calculation?

The RPM (Revolutions Per Minute) from voltage calculation determines the rotational speed of an electric motor based on the applied voltage and the motor's kV rating (RPM per volt).

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( Voltage \) — Applied voltage in volts (V)
• \( kV \) — Motor constant in RPM per volt (RPM/V)

Explanation: The kV rating indicates how many RPM the motor will turn per volt applied (with no load). Multiplying by the actual voltage gives the theoretical maximum RPM.

3. Importance of RPM Calculation

Details: Knowing the expected RPM helps in selecting the right motor for an application, predicting performance, and ensuring the motor operates within its designed parameters.

4. Using the Calculator

Tips: Enter the voltage applied to the motor and the motor's kV rating. Both values must be positive numbers. The result is the theoretical no-load RPM.

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 friction, current draw, and efficiency losses.

Q2: What is a typical kV rating for motors?
A: kV ratings vary widely: drone motors might be 1000-3000 RPM/V, while industrial motors might be 10-100 RPM/V.

Q3: Does battery voltage affect RPM?
A: Yes, higher voltage means higher RPM (assuming the motor can handle it). A 12V motor at 6V will run at half speed.

Q4: Why is my actual RPM lower than calculated?
A: Load, inefficiency, voltage drop under load, and temperature all reduce actual RPM below the theoretical value.

Q5: Can I use this for brushless and brushed motors?
A: Yes, the basic calculation works for both, though brushless motors typically have higher kV ratings.