The article Introduction of How A Brushless DC Motor Works explains how brushless dc motor for sale works. In a typical dc motor, there are permanent magnets on the outside and a spinning armature on the inside. The permanent magnets are stationary, so they are called the stator. The armature rotates, so 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 keep it spinning, you have to change the poles of the electromagnet. The brushes handle this change in polarity. They make contact with two spinning electrodes attached to the armature and flip the magnetic polarity of the electromagnet as it spins.
This setup works and is simple and cheap to manufacture, but it has a lot of problems:
- The brushes eventually wear
- Because the brushes are
making/breaking connections, you get sparking and electrical noise.
- The brushes limit the
maximum speed of the motor.
- Having the electromagnet in
the center of the motor makes it harder to cool.
- The use 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 motor inside out" and eliminate the brushes. In a brushless dc 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 charge up the electromagnets as the shaft turns. This system has all sorts of advantages: Because a computer controls the motor instead of mechanical brushes, it's more precise. The computer can also factor the speed of the motor into 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.
An electric motor is all about magnets and magnetism: A stepper motor for sale uses magnets to create motion. If you have ever played with magnets you know about the fundamental law of all magnets: Opposites attract and likes repel. So if you have two bar magnets with their ends marked "north" and "south," then the north end of one magnet will attract the south end of the other. On the other hand, the north end of one magnet will repel the north end of the other (and similarly, south will repel south). Inside an electric motor, these attracting and repelling forces create rotational motion. The motor being dissected here is a simple electric motor that you would typically find in a toy.