The engine from a 3.5″ floppy disk drive. The coils, arranged radially, are produced from copper wire coated with blue insulation. The well balanced rotor (upper right) has been eliminated and turned upside-down. The grey ring inside its cup is a long lasting magnet.
A brushless DC electric motor (BLDC motor or BL engine), also known as electronically commutated electric motor (ECM or EC electric motor) and synchronous DC motors, are synchronous motors powered by DC electrical power via an inverter or switching power which creates an AC electric current to drive each stage of the motor with a closed loop controller. The controller provides pulses of current to the motor windings that control the acceleration and torque of the engine.
The construction of a brushless electric motor system is normally similar to a long lasting magnet synchronous electric motor (PMSM), but can also be a switched reluctance engine, or an induction (asynchronous) motor.[1]
The advantages 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 places as pc 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 lasting magnets on the Transmission Chain outside and a spinning armature on the inside. The long lasting 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 operate electricity into this electromagnet, it generates a magnetic field in the armature that attracts and repels the magnets in the stator. Therefore the armature spins through 180 degrees. To maintain it spinning, you need to change the poles of the electromagnet. The brushes deal with this change in polarity. They speak to two spinning electrodes attached to the armature and flip the magnetic polarity of the electromagnet as it spins.
his setup works and is simple 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 maximum 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 on how many poles the armature can have.
With the advent of cheap computers and power transistors, it became possible to “turn the engine inside out” and get rid of the brushes. In a brushless DC engine (BLDC), you put the long lasting magnets on the rotor and you move the electromagnets to the stator. You then use a computer (linked to high-power transistors) to charge up the electromagnets as the shaft turns. This technique has a variety of advantages:
Because a computer controls 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 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 extremely easy to cool.
You can have a lot of electromagnets on the stator for more precise control.
The only disadvantage of a brushless motor is its higher initial cost, nevertheless, you can often recover that cost through the greater efficiency over the life span of the motor.