Brushed and brushless motors have become integral components in the world of drones. However, understanding the fundamental difference between the two is crucial for any enthusiast or professional seeking to maximize their drone’s performance. While both motors serve the same purpose of powering the propellers, the key dissimilarity lies in their construction and mechanism. This article aims to shed light on the disparity between brushed and brushless motors, exploring their respective advantages and limitations in the realm of drone technology.
Construction
Brushed Motors
Brushed motors consist of a rotating armature (or rotor) and a stationary set of magnets (or stator). The armature is made up of a series of coils wound around an iron core, which generates a magnetic field when electricity passes through it. This magnetic field interacts with the magnets in the stator, causing the rotor to rotate.
Brushless Motors
Brushless motors, on the other hand, have a more complex construction. Instead of using brushes to transfer electricity to the armature, they utilize a controller or electronic speed controller (ESC) to control the flow of current to the motor windings. The stator consists of a series of coils, while the rotor features a permanent magnet. The ESC determines the timing and sequence of current flow to the different sections of the motor, resulting in its rotation.
Working Principle
Brushed Motors
In brushed motors, the brushes and commutator play a crucial role in the working principle. The brushes supply current to the armature through the commutator, which constantly switches the direction of current flow to ensure the rotor continues to rotate. This mechanical switching of current direction creates friction and wear on the brushes and commutator, leading to a shorter lifespan of the motor.
Brushless Motors
In brushless motors, the functioning is entirely electronic. The ESC receives input signals from the flight controller and uses this information to control the flow of current to the motor windings. By energizing the appropriate coils at the right time, the ESC can create a rotating magnetic field that interacts with the permanent magnet on the rotor, causing it to spin. As no physical commutation is required, brushless motors have a longer lifespan and higher efficiency than their brushed counterparts.
Efficiency
Brushed Motors
Brushed motors are known to be relatively inefficient. This is primarily due to the friction and heat generated by the brushes and commutator. The constant wear on these components also contributes to efficiency loss over time. As a result, brushed motors typically waste more energy and produce less torque compared to brushless motors.
Brushless Motors
Brushless motors are significantly more efficient than brushed motors. The electronic commutation eliminates the need for physical brushes and commutators, reducing friction and heat. This allows brushless motors to convert a higher percentage of electrical energy into rotational mechanical energy, resulting in greater efficiency. The absence of brushes also means there is no wear and tear, allowing brushless motors to maintain their efficiency over a longer period.
Power Output
Brushed Motors
Brushed motors are generally capable of producing high amounts of torque, making them suitable for applications that require high initial power. However, their power output tends to decrease as the motor speeds up, limiting their overall performance in terms of sustained power delivery.
Brushless Motors
Brushless motors offer a more consistent power output throughout their operating range. They can maintain high levels of torque even at high speeds, providing a more reliable and responsive power delivery. This makes brushless motors more suitable for applications where sustained power is crucial, such as drones that need to maintain stable flight characteristics.
Speed Control
Brushed Motors
Brushed motors can be speed-controlled by varying the voltage applied to them. By increasing or decreasing the voltage, the speed of the motor can be adjusted. However, this method of speed control is relatively basic and does not offer fine-grained control over the motor’s performance.
Brushless Motors
Brushless motors offer more advanced speed control options. By adjusting the timing and sequence of current flow to the motor windings through the ESC, precise control over the motor’s speed and performance can be achieved. This allows for more accurate maneuverability and responsiveness in drones, making brushless motors the preferred choice for drone applications.
Maintenance
Brushed Motors
Brushed motors require regular maintenance due to the wear and tear associated with the brushes and commutator. The brushes tend to wear down over time and need to be replaced periodically to ensure proper motor functioning. Additionally, the commutator may require cleaning to remove debris and carbon buildup. Regular maintenance is essential to prolong the lifespan and optimize the performance of brushed motors.
Brushless Motors
Brushless motors require less maintenance compared to brushed motors. Since they do not have brushes or a commutator, there is no need for regular replacement or cleaning. However, proper care should still be taken to ensure the motor’s cooling system is functioning efficiently. Overheating can negatively impact the performance and lifespan of brushless motors, so monitoring temperature levels and providing adequate cooling is important.
Durability
Brushed Motors
Brushed motors are generally less durable compared to brushless motors due to the mechanical nature of their operation. The brushes and commutator are prone to wear and failure over time, resulting in reduced performance and eventual motor failure. Additionally, the mechanical switching of current direction in brushed motors creates more friction, leading to additional wear and tear on the motor components.
Brushless Motors
Brushless motors are designed for durability and longevity. Without the brushes and commutator, they experience less wear and are less prone to failure. This allows brushless motors to have a longer lifespan and better overall durability compared to brushed motors. The electronic nature of their operation also reduces the chances of mechanical failure, making them more reliable in demanding applications such as drones.
Cost
Brushed Motors
Brushed motors are typically less expensive compared to brushless motors. The simpler construction and mechanical components result in lower manufacturing costs, making brushed motors a more affordable option. However, it is important to consider the potential additional costs associated with maintenance and replacement of brushes and commutators over time.
Brushless Motors
Brushless motors are generally more expensive compared to brushed motors due to their more advanced construction and electronic components. The need for an ESC and the complexity of the electronic system contribute to the higher cost. However, the improved efficiency, durability, and performance of brushless motors can often outweigh the initial investment, making them worth the higher price for certain applications.
Noise
Brushed Motors
Brushed motors tend to generate more noise during operation. The brushes and commutator cause mechanical vibrations, resulting in audible noise. This can be a consideration in applications where noise reduction is important, such as drone photography or cinematography.
Brushless Motors
Brushless motors produce significantly less noise compared to brushed motors due to their electronic commutation. The absence of brushes and the smooth operation of the electronic speed control system results in quieter motor operation. This makes brushless motors a preferred choice in applications where noise reduction is a priority.
Applications
Brushed Motors
Brushed motors find their applications in various industries, including automotive, household appliances, and low-cost drones. Their high initial torque and affordability make them suitable for applications where sustained power delivery and precision speed control are not critical requirements.
Brushless Motors
Brushless motors have gained popularity in industries such as aerospace, robotics, and high-performance drones. Their efficiency, durability, speed control capabilities, and quieter operation make them ideal for applications where precise control, reliability, and power output are paramount. In particular, brushless motors are extensively used in the drone industry as they offer enhanced flight characteristics and longer flight times.
In conclusion, brushed and brushless motors differ in construction, working principle, efficiency, power output, speed control, maintenance, durability, cost, noise generation, and applications. While brushed motors are simpler and more affordable, brushless motors offer higher efficiency, better performance, and longer lifespan. The choice between these motor types depends on specific application requirements, with brushless motors being preferable in situations that demand greater precision, reliability, and power.