I. Advantages of Brushless Motors
(1) Brushless, low interference
The most direct change from brushless motors is the elimination of electrical sparks generated during the operation of brushed motors, which greatly reduces the interference of electrical sparks on remote control wireless devices.
(2) Low noise and smooth operation
Brushless motors, without brushes, experience significantly reduced friction during operation, resulting in smoother running and much lower noise. This advantage greatly enhances the stability of the model's operation.
(3) Long lifespan and low maintenance cost
Without brushes, the wear and tear on brushless motors primarily occurs in the bearings. From a mechanical perspective, brushless motors are almost maintenance-free, requiring only dust removal when necessary. A comparison clearly shows the advantages of brushless motors over brushed motors. However, nothing is absolute. Brushed motors possess superior low-speed torque performance and high torque characteristics that brushless motors cannot replace. Nevertheless, considering the ease of use of brushless motors, with the decreasing cost of brushless controllers and the development and market competition of brushless technology both domestically and internationally, brushless power systems are experiencing rapid development and widespread adoption, which has greatly promoted the development of model motors.
II. Disadvantages of Brushed Motors
(1) High friction and high wear
Veteran model enthusiasts have encountered this problem when playing with brushed motors: after using the motor for a period of time, it is necessary to open the motor to clean the carbon brushes, which is time-consuming and laborious, and the maintenance intensity is no less than a major house cleaning.
(2) High heat generation, short lifespan
Due to the structure of brushed motors, the contact resistance between the brushes and the commutator is very high, resulting in a high overall resistance of the motor and making it prone to overheating. Since permanent magnets are heat-sensitive elements, if the temperature is too high, the magnets will demagnetize, causing a decrease in motor performance and affecting the lifespan of the brushed motor.
(3) Low efficiency and low output power
The overheating problem of brushed motors mentioned above is largely due to the fact that the current does work on the internal resistance of the motor, so a large amount of electrical energy is converted into heat energy. Therefore, the output power of brushed motors is not high and the efficiency is not high.
III. Other differences of brushless motors
(1) Scope of application:
Brushless motors are typically used in equipment with high control requirements and high speeds, such as model airplanes and precision instruments, where motor speed control is strict and very high speeds are required.
Brushed motors: Brushed motors are commonly used in power equipment, such as hair dryers, factory electric motors, and household range hoods. In addition, series-wound motors can also reach very high speeds, but due to the wear of carbon brushes, their service life is not as good as that of brushless motors.
(2) Service life:
Brushless motors typically have a lifespan in the tens of thousands of hours, but the lifespan can vary greatly depending on the bearings used.
Carbon brush motors: The continuous working life of brushed motors is usually several hundred to more than 1,000 hours. When they reach the limit of use, the carbon brushes need to be replaced, otherwise it will easily cause wear on the bearings.
(3) Effects of use:
Brushless motors: They are usually digitally frequency-controlled, highly controllable, and can easily achieve speeds from a few revolutions per minute to tens of thousands of revolutions per minute.
Carbon brush motors: Old carbon brush motors generally have a constant operating speed after starting, and speed adjustment is not easy. Series motors can also reach 20,000 rpm, but their service life will be relatively short.
(4) Energy saving:
Comparatively, brushless motors controlled by frequency conversion technology are much more energy-efficient than series-wound motors, most notably in variable frequency air conditioners and refrigerators.
(5) Future maintenance:
Carbon brush motors require carbon brush replacement; failure to replace them in time can damage the motor. Brushless motors, on the other hand, have a much longer lifespan, typically more than 10 times that of brushed motors. However, they do require replacement if they break down, but routine maintenance is generally unnecessary.
(6) Noise is not related to whether it is a brushed motor or not; it mainly depends on the fit between the bearings and the internal components of the motor.
(7) In addition to the external dimensions (outer diameter, length, shaft diameter, etc.), weight, voltage range, no-load current, maximum current, etc., the parameters of the model brushless motor also include an important indicator, KV value. This value is a unique performance parameter of the brushless motor and is an important data for judging the performance characteristics of the brushless motor.
