4 major differences between DC brushed motors and DC brushless motors.
In the previous two articles, Topband Motor brushed motors and brushless motors respectively. At the same time, we also learned that both brushed and brushless motors can use DC power. So today, let's take a look at the differences between the two.
The main differences between DC brushed motors and DC brushless motors are as follows:
1. Different working principles
The working principle of a DC brushed motor: When the motor rotates, the carbon brush slides on the commutator, generating a rotating magnetic field that is attracted by the static magnetic field of the stator. The current in the armature and stator windings is provided by a battery or other DC power source to provide a constant DC voltage to the battery (or DC power source).
The working principle of a brushless DC motor is to attach magnetized permanent magnets to the rotor of the motor, detect the polarity of the motor rotor, control the start, stop, and braking of the motor by the driver, control the switching of various power tubes in the inverter bridge, generate continuous torque, and control and adjust the speed, providing protection and display, etc.
2. Different performance
DC brushed motors have a simple mechanism and are easy to produce and process. They have been widely used since the 19th century, with mature technological development. DC brushed motors have higher output power and control accuracy, with a control accuracy of up to 0.01 millimeters, allowing moving parts to stop almost anywhere they want. All precision machine tools use DC motors to control accuracy.
Brushless DC motors have only been gradually put into commercial operation in the past decade, and the technology is relatively immature. Brushless motors have high starting resistance (inductive impedance) and relatively low starting torque. Brushless DC motors have lower interference, lower noise, longer lifespan, and lower maintenance costs.
3. Different structural compositions
The basic components of a DC brushed motor include the stator, rotor, brushes, and commutator. The interaction between the stator and rotor magnetic fields drives the motor to rotate.
A brushless DC motor consists of a motor body and a driver. The stator winding of the motor is mostly connected in a three-phase symmetrical star shape, and the driver is composed of power electronic devices and integrated circuits.
4. Different speed regulation methods
In fact, the control of both types of motors is voltage regulation, but due to the use of electronic commutation in brushless DC, digital control is required to achieve it, while brushed DC is controlled through carbon brush commutation using traditional analog circuits such as thyristors, which is relatively simple.
Compared to brushed DC motors, brushless DC motors remove brushes, and the most direct change is the absence of electric sparks generated during the operation of brushed motors, which greatly reduces the interference of electric sparks on remote control radio equipment.
Brushless motors without electric brushes greatly reduce friction during operation, resulting in smooth operation and much lower noise. This advantage is a huge support for the stability of model operation. Without electric brushes, the wear of brushless motors is mainly on the bearings. From a mechanical perspective, brushless motors are almost maintenance free motors, and when necessary, only some dust removal maintenance is needed.
