The motor from a 3.5″ floppy disk drive. The coils, arranged radially, are produced from copper wire covered with blue insulation. The well balanced rotor (upper right) has been removed and switched upside-down. The grey band inside its cup is a permanent magnet.
A brushless DC electric motor (BLDC engine or BL electric motor), also known as electronically commutated engine (ECM or EC motor) and synchronous DC motors, are synchronous motors powered by DC electricity via an inverter or switching power which creates an AC electric current to drive each phase of the motor via a closed loop controller. The controller provides pulses of current to the engine windings that control the acceleration and torque of the engine.

The construction of a brushless engine system is typically similar to a permanent magnet synchronous motor (PMSM), but can also be a switched reluctance motor, or an induction (asynchronous) motor.[1]

The benefits of a brushless electric motor over brushed motors are high power to weight ratio, high speed, electronic control, and lower maintenance. Brushless motors discover applications in such areas as pc peripherals (disk drives, printers), hand-held power tools, and vehicles ranging from model aircraft to automobiles.
In a typical DC motor, there are long term Drive Chain magnets externally and a spinning armature inside. The long term magnets are stationary, so they are called the stator. The armature rotates, so that it is called the rotor.

The armature contains an electromagnet. When you run 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 maintain 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 mounted on the armature and flip the magnetic polarity of the electromagnet as it spins.
his setup works and is easy and cheap to manufacture, but it includes a lot of problems:

The brushes eventually wear out.
Because the brushes are making/breaking connections, you get sparking and electrical noi
The brushes limit the utmost speed of the motor.
Having the electromagnet in the heart 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 became feasible to “turn the electric motor inside out” and eliminate the brushes. In a brushless DC engine (BLDC), you place the long term magnets on the rotor and you move the electromagnets to the stator. You then use a computer (connected to high-power transistors) to charge up the electromagnets as the shaft turns. This technique has a variety of advantages:
Because a computer regulates the motor instead of mechanical brushes, it’s more precise. The computer may also factor the quickness of the motor in to the equation. This makes brushless motors more efficient.
There is no sparking and much 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 lot of electromagnets on the stator for more precise control.
The only disadvantage of a brushless engine is its higher initial cost, nevertheless, you can often recover that cost through the greater efficiency over the life of the motor.