The engine from a 3.5″ floppy disk drive. The coils, arranged radially, are manufactured from copper wire covered with blue insulation. The balanced rotor (upper right) has been removed and switched upside-down. The grey ring inside its cup is a long term magnet.
A brushless DC electrical motor (BLDC engine or BL engine), also referred to as electronically commutated engine (ECM or EC motor) and synchronous DC motors, are synchronous motors powered by DC electrical power via an inverter or switching power which generates an AC electric energy to drive each stage of the motor via a closed loop controller. The controller provides pulses of current to the electric motor windings that control the quickness and torque of the engine.
The construction of a brushless engine system is typically similar to a permanent magnet synchronous engine (PMSM), but can also be a switched reluctance motor, or an induction (asynchronous) motor.[1]
The benefits of a brushless motor over brushed motors are high capacity to weight ratio, high speed, electronic control, and lower maintenance. Brushless motors find applications in such places as pc peripherals (disk drives, printers), hand-held power equipment, and vehicles which range from model aircraft to automobiles.
In a typical DC electric motor, there are long lasting magnets on the outside and a spinning armature inside. The permanent magnets are stationary, so they are called the stator. The armature rotates, so it is called the rotor.
The armature contains an electromagnet. When you operate electricity into this electromagnet, it creates a magnetic field in the armature that attracts and repels the magnets in the stator. So the armature spins through 180 degrees. To keep it spinning, you need to change the poles 
of the electromagnet. The brushes manage this alter in polarity. They make contact with two spinning electrodes attached to the armature and flip the magnetic polarity of the electromagnet as it spins.
his setup works and is easy and cheap to produce, but it includes a lot of problems:
The brushes eventually degrade.
As the brushes are producing/breaking connections, you get sparking and electrical noi
The brushes limit the maximum speed of the engine.
Having the electromagnet in the center of the motor makes it harder to cool.
The utilization of brushes puts a limit about how many poles the armature can have.
With the advent of cheap computers and power transistors, it Transmission Chain became feasible to “turn the electric motor inside out” and remove the brushes. In a brushless DC motor (BLDC), you put the long term magnets on the rotor and you move the electromagnets to the stator. Then you use a computer (linked to high-power transistors) to replenish the electromagnets as the shaft turns. This system has a variety of advantages:
Because a computer handles the motor instead of mechanical brushes, it’s more precise. The computer can also factor the acceleration of the motor in to the equation. This makes brushless motors better.
There is no sparking and far less electrical noise.
There are no brushes to wear out.
With the electromagnets on the stator, they are very easy to cool.
You can have a whole lot of electromagnets on the stator for more precise control.
The only disadvantage of a brushless electric motor is its higher initial cost, nevertheless, you could recover that cost through the greater efficiency over the life span of the motor.
