How Brushless Motors Work & How to Test Them

Brushless motors, also known as BLDC motors (short for Brushless DC motors), are electric motors that use a permanent magnet rotor and a stator with windings to produce rotational motion.

Here is a step-by-step explanation of how a brushless motor works:

  1. The motor’s stator contains a series of windings or coils arranged in a specific pattern around the inside of the motor casing.
  2. The motor’s rotor contains one or more permanent magnets, arranged in a specific pattern to interact with the magnetic field produced by the stator windings.
  3. The stator windings are connected to an electronic speed controller (ESC) that manages the flow of electricity to the motor.
  4. When electricity flows through the stator windings, it creates a magnetic field that interacts with the magnetic field produced by the rotor magnets.
  5. The interaction between the stator and rotor magnetic fields produces a force that causes the rotor to spin.
  6. As the rotor spins, the ESC monitors the speed and position of the rotor. It adjusts the flow of electricity to the stator windings to maintain the desired speed and direction of rotation.

Unlike traditional brushed motors, brushless motors do not rely on brushes to transfer electrical current to the rotor, which reduces wear and tear and increases efficiency and lifespan. The use of permanent magnets in the rotor also contributes to brushless motors’ higher efficiency and performance than their brushed counterparts.

Brushless and Brushed, What’s the Difference?

Brushless and brushed motors are different types of electric motors that use other mechanisms to produce rotational motion. The main differences between these two types of motors are their design and function.

Brushed Motors:

A brushed motor consists of a rotor, a stator, and brushes. The rotor contains one or more magnets, and the stator has a series of wire coils that produce a magnetic field when electricity flows through them. The brushes, made of carbon, transfer electricity to the rotor and keep it spinning.

The brushes in a brushed motor come into contact with the commutator, which is a component that switches the direction of the current flowing through the motor’s coils. As the brushes wear down over time, the motor’s performance can deteriorate, and they may need to be replaced.

Brushless Motors:

On the other hand, a brushless motor uses a different design that eliminates the need for brushes. Instead of a commutator and bushes, a brushless motor uses a control circuit to switch the direction of the current flowing through the motor’s coils.

The rotor in a brushless motor contains permanent magnets, while the stator has wire coils that create a magnetic field. When electricity flows through the coils, the interaction between the magnetic fields of the rotor and stator produces rotational motion.

Brushless motors are more efficient than brushed motors, as they have fewer moving parts and experience less wear and tear. They are also quieter, more reliable, and require less maintenance.

In summary, the main differences between brushed and brushless motors are their design andtheir design and function. Brushed motors use brushes to transfer electricity to the rotor, while brushless motors use a control circuit. Brushless motors are more efficient, and reliable and require less maintenance than brushed motors.

Best Brushless FPV Drone Motor:

There are many excellent brushless motors available on the market for FPV drones. The best motor for your drone will depend on your specific requirements, such as the size and weight of your drone, the type of propellers you are using, and the flight characteristics you are looking for. However, here are a few popular options that are known for their performance and reliability:

  1. T-Motor F40 Pro II: This motor is a popular choice among FPV drone pilots for its high power output and smooth operation. It is available in different KV ratings to suit different propeller sizes and has a durable design with a steel shaft and high-temperature magnets.
  2. EMAX RS2205-S: This motor is another popular choice among FPV pilots, known for its high-quality construction and smooth performance. It has a strong thrust-to-weight ratio available in different KV ratings to match different propeller sizes.
  3. BrotherHobby Returner R3: This motor is designed for high-performance racing drones and has a robust and lightweight design with high-quality components. It has a smooth and responsive performance and is available in different KV ratings.
  4. Racerstar BR2205: This motor is a more affordable option but still offers good performance for its price. It has a strong and durable design with high-temperature magnets and is available in different KV ratings to suit different propeller sizes.

Remember, when choosing a motor for your FPV drone, it’s essential to consider not only the motor’s performance but also its compatibility with your other components and your specific requirements.

How to test Brushless Drone Motors?

There are several ways to test brushless motors to ensure they are functioning correctly and performing as expected. Here are a few methods:

  1. Motor Spin Test: One simple test is to power the motor with a low-voltage battery and check if it spins smoothly without vibrations or noise. You can use a battery tester or a power supply to power the motor and a propeller or a small load to put a small bag on the motor.
  2. Thrust Test: To test the motor’s maximum thrust, you can use a thrust stand, which measures the amount of thrust the motor generates at different speeds. You can use a data logger to record the motor’s performance and compare it to the manufacturer’s specifications.
  3. Current and Voltage Test: You can measure the motor’s current draw and voltage using a multimeter to ensure they are within the manufacturer’s recommended range. High current interest or voltage can indicate a problem with the motor or the wiring.
  4. Temperature Test: You can also test the motor’s temperature after running it for a few minutes to ensure it’s not overheating. You can use an infrared thermometer or a thermal camera to measure the motor’s temperature and compare it to the manufacturer’s recommended maximum temperature.

It’s essential to follow proper safety precautions when testing motors, such as wearing protective gear and avoiding touching the rotating parts of the motor. Additionally, it’s a good idea to refer to the manufacturer’s documentation for specific testing procedures and recommended test equipment.


In conclusion, brushless motors are widely used in various applications, including drones, RC cars, and electric vehicles, due to their higher efficiency, power output, and reliability than brushed motors. They operate by using a series of permanent magnets on the rotor and electromagnets on the stator to produce rotational motion without any physical contact between the two. This design allows brushless motors to operate with less friction, less wear and tear, and less heat generation, resulting in a longer lifespan and improved performance. Additionally, brushless motors require electronic speed controllers to control their speed and direction. Their performance can be optimized by selecting the correct motor size, KV rating, and propeller size for the specific application. Brushless motors offer several advantages over brushed motors and have revolutionized the world of electric motors.

Mepsking FPV Forum, where you can learn everything about drone and flying skills. Check mepsking store if you want to buy drone parts.

Tutorials, Hacks and How-to

Can FPV Drones Hover?(Reasons and How to Make it Hover)

2023-2-28 10:19:33

Tutorials, Hacks and How-to

Complete Guide to FPV Drone Propellers

2023-2-28 10:25:49

0 comment AAuthor MAdministrator
    No Comments Yet. Be the first to share what you think!
Message Message