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 correct) has been removed and turned upside-down. The grey ring inside its glass is a long term magnet.
A brushless DC electrical motor (BLDC engine or BL electric motor), also called electronically commutated engine (ECM or EC engine) and synchronous DC motors, are synchronous motors powered by DC electrical power via an inverter or switching power supply which generates an AC electric energy to drive each stage of the motor with a closed loop controller. The controller provides pulses of current to the engine windings that control the quickness and torque of the engine.
The construction of a brushless motor system is typically similar to a long lasting magnet synchronous engine (PMSM), but may also be a switched reluctance electric motor, or an induction (asynchronous) motor.
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 locations as computer peripherals (disk drives, printers), hand-held power tools, and vehicles which range from model aircraft to automobiles.
In a typical DC engine, there are long lasting magnets on the outside and a spinning armature inside. The long term magnets are stationary, therefore 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 generates a magnetic field in the armature that attracts and repels the magnets in the stator. Therefore the armature spins through 180 degrees. To keep it spinning, you have to change the poles of the electromagnet. The brushes manage this alter 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 produce, but it has 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 maximum speed of the engine.
agricultural Chain Having the electromagnet in the heart of the motor makes it harder to cool.
The use 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 remove the brushes. In a brushless DC electric motor (BLDC), you place the long lasting 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 technique has a variety of advantages:
Because a computer handles the motor rather than mechanical brushes, it’s more precise. The computer can also factor the quickness of the motor into the equation. This makes brushless motors more efficient.
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 motor is its higher initial cost, nevertheless, you could recover that cost through the higher efficiency over the life of the motor.