The electric motor from a 3.5″ floppy disk drive. The coils, arranged radially, are produced from copper wire covered with blue insulation. The balanced rotor (upper correct) has been removed and switched upside-down. The grey band inside its cup is a long lasting magnet.
A brushless DC electrical motor (BLDC engine or BL motor), also referred to as electronically commutated electric motor (ECM or EC electric motor) and synchronous DC motors, are synchronous motors powered by DC electricity via an inverter or Conveyor Chain switching power which generates an AC electric energy 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 electric 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 advantages of a brushless engine over brushed motors are high capacity to weight ratio, high speed, electronic control, and lower maintenance. Brushless motors find applications in such locations as pc peripherals (disk drives, printers), hand-held power tools, and vehicles which range from model aircraft to automobiles.
In a typical DC motor, there are permanent magnets on the outside and a spinning armature inside. The long lasting magnets are stationary, therefore they are called the stator. The armature rotates, so that it is named the rotor.
The armature contains an electromagnet. When you run electricity 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 need to change the poles of the electromagnet. The brushes deal with this change 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 simple and cheap to produce, but it includes a lot of problems:
The brushes eventually wear out.
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 heart of the motor makes it harder to cool.
The usage of brushes puts a limit on 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 get rid of the brushes. In a brushless DC electric motor (BLDC), you put the permanent magnets on the rotor and you move the electromagnets to the stator. Then you use a computer (connected to high-power transistors) to replenish the electromagnets as the shaft turns. This system 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 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 whole lot of electromagnets on the stator for more precise control.
The only drawback of a brushless motor is its higher initial cost, nevertheless, you could recover that cost through the higher efficiency over the life span of the motor.