The engine from a 3.5″ floppy disk drive. The coils, arranged radially, are produced from copper wire coated with blue insulation. The balanced rotor (upper correct) has been eliminated and switched upside-down. The grey ring inside its cup is a long term magnet.
A brushless DC electrical motor (BLDC motor or BL engine), also referred to as electronically commutated electric motor (ECM or EC electric motor) and Stainless Steel Chain synchronous DC motors, are synchronous motors powered by DC electricity via an inverter or switching power supply which generates an AC electric current to drive each stage of the motor via a closed loop controller. The controller provides pulses of current to the motor windings that control the velocity and torque of the electric motor.
The construction of a brushless motor system is typically similar to a long term magnet synchronous engine (PMSM), but may also be a switched reluctance engine, 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 discover applications in such locations as computer peripherals (disk drives, printers), hand-held power equipment, and vehicles ranging from model aircraft to automobiles.
In a typical DC electric motor, there are long term magnets on the outside and a spinning armature inside. The permanent magnets are stationary, so they are known as the stator. The armature rotates, so that it is named the rotor.
The armature contains an electromagnet. When you operate electrical power into this electromagnet, it creates a magnetic field in the armature that draws in and repels the magnets in the stator. So the armature spins through 180 degrees. To maintain it spinning, you have to modify 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 since it spins.
his setup works and is easy and cheap to produce, but it includes a lot of problems:
The brushes eventually wear out.
Because the brushes are producing/breaking connections, you get sparking and electrical noi
The brushes limit the utmost speed of the electric 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 engine inside out” and remove the brushes. In a brushless DC motor (BLDC), you put the permanent magnets on the rotor and you move the electromagnets to the stator. You then use a computer (linked to high-power transistors) to replenish 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 into the equation. This makes brushless motors more efficient.
There is absolutely no sparking and far less electrical noise.
There are no brushes to degrade.
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 motor is its higher initial cost, but you could recover that cost through the greater efficiency over the life span of the motor.