Brushless DC Motors

Also known as BLDC motors, brushless DC motors are electronically commutated motors which are powered by a DC electric source via an integrated or switching power supply. This produces an AC electric current which is then used to drive the motor. The rotor can be a permanent magnetic synchronous motor, a switched reluctance motor or an induction motor. They are sometimes chosen over brushed motors as they are more efficient as less power is lost to heat. There are a number of design changes to the basic brushless DC motor. There are different physical configurations: conventional and outrunner. In conventional, the permanent magnets are part of the rotor while in the outrunner, the radial relationship between the coils and magnets is reversed. The electrical winding configurations can be either delta or wye (Y). Brushless DC motors have a number of applications. In heating, ventilation and air conditioning systems, they allow it to be programmed by a built-in microprocessor. They are also a component of industrial automation and motion control systems. On a smaller scale they can be found in computer hard drives, cooling fans for electronic equipment, cordless power tools as well as CD or DVD players.