1. What is the Brushless Motor Speed Equation?

The brushless motor speed equation calculates the rotational speed (RPM) of a brushless DC motor based on its Kv rating and the applied voltage. This simple relationship helps predict motor performance under different voltage conditions.

2. How Does the Calculator Work?

The calculator uses the fundamental brushless motor equation:

Where:

• \( RPM \) — Rotational speed in revolutions per minute
• \( Kv \) — Motor velocity constant in RPM per volt
• \( V \) — Applied voltage in volts

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

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 safe speed range.

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 speed I'll get in my application?
A: This is the theoretical no-load speed. Actual speed will be lower due to load, friction, and other factors.

Q2: What affects a motor's Kv rating?
A: Kv is determined by the motor's design - number of windings, magnets, and overall construction. Lower Kv means more torque but less speed at a given voltage.

Q3: Can I use this for brushed motors?
A: The concept is similar, but brushed motors typically have different performance characteristics and the calculation may be less accurate.

Q4: What if I use a different voltage than rated?
A: The equation still applies - motor speed will scale linearly with voltage, but exceeding rated voltage may damage the motor.

Q5: How does load affect the actual RPM?
A: Under load, the motor will draw more current and the RPM will drop due to increased back EMF and voltage drop across internal resistance.