1 The compare brushless with Brush motor
Brushed DC motors develop a maximum torque when stationary, linearly decreasing as velocity increases. Some limitations of brushed motors can be overcome by brushless motors; they include higher efficiency and a lower susceptibility to mechanical wear. These benefits come at the cost of potentially less rugged, more complex, and more expensive control electronics.
A typical brushless motor has permanent magnets which rotate around a fixed armature, eliminating problems associated with connecting current to the moving armature. An electronic controller replaces the brush/commutator assembly of the brushed DC motor, which continually switches the phase to the windings to keep the motor turning. The controller performs similar timed power distribution by using a solid-state circuit rather than the brush/commutator system.
Brushless motors offer several advantages over brushed DC motors, including high torque to weight ratio, more torque per watt (increased efficiency), increased reliability, reduced noise, longer lifetime (no brush and commutator erosion), elimination of ionizing sparks from the commutator, and overall reduction of electromagnetic interference (EMI). With no windings on the rotor, they are not subjected to centrifugal forces, and because the windings are supported by the housing, they can be cooled by conduction, requiring no airflow inside the motor for cooling. This in turn means that the motor's internals can be entirely enclosed and protected from dirt or other foreign matter.
Brushless motor commutation can be implemented in software using a microcontroller or microprocessor computer, or may alternatively be implemented in analogue hardware, or in digital firmware using an FPGA. Commutation with electronics instead of brushes allows for greater flexibility and capabilities not available with brushed DC motors, including speed limiting, "micro stepped" operation for slow and/or fine motion control, and a holding torque when stationary. Controller software can be customized to the specific motor being used in the application, resulting in greater commutation efficiency.
The maximum power that can be applied to a brushless motor is limited almost exclusively by heat;[ too much heat weakens the magnets and may damage the winding's insulation.
When converting electricity into mechanical power, brushless motors are more efficient than brushed motors. This improvement is largely due to the frequency at which the electricity is switched determined by the position sensor feedback. Additional gains are due to the absence of brushes, which reduces mechanical energy loss due to friction. The enhanced efficiency is greatest in the no-load and low-load region of the motor's performance curve. Under high mechanical loads, brushless motors and high-quality brushed motors are comparable in efficiency.
Environments and requirements in which manufacturers use brushless-type DC motors include maintenance-free operation, high speeds, and operation where sparking is hazardous (i.e. explosive environments) or could affect electronically sensitive equipment.
2 The advantage of the Brushless
2.1 brushless, low interference
In addition to the brushless motor brush, the most immediate change is without the motor running when the electric spark, thus greatly reduce the electric spark interference of remote radio equipment.
2.2 low noise, smooth operation
Brushless motor without brush, less friction force during operation, smooth running, low noise will many of the advantages of model running stability is a huge support.
2.3 long service life and low maintenance cost
Without the brush, brushless motor is mainly on the bearing, from the mechanical point of view, brushless motor is almost a maintenance-free motor, when necessary, the only need to do some cleaning maintenance. Next comparison, know brushless motor relative to have advantage in where the brush motor, but everything is not absolute, a brush motor torque at low speed performance, large torque and other performance characteristics is irreplaceable brushless motor, but in the context of use and ease of brushless motor, with the decline in the cost of brushless controller and brushless technology development and market competition both at home and abroad, brushless power system is the development and popularity of high-speed stage, it also greatly promote the development of the model of motion.