A motor converts supplied electrical energy into mechanical energy. Various types of motors are in common use. Among these, brushless DC motors (BLDC) feature high efficiency and excellent controllability, and are widely used in many applications. The BLDC motor has power-saving advantages relative to other motor types.

There are two types of commonly used DC motors: Brushed motors, and brushless motors (or BLDC motors). As their names imply, DC brushed motors have brushes, which are used to commutate the motor to cause it to spin. Brushless motors replace the mechanical commutation function with electronic control.

In many applications, either a brushed or brushless DC motor can be used. They function based on the same principles of attraction and repulsion between coils and permanent magnets. Both have advantages and disadvantages that may cause you to choose one over the other, depending on your application’s requirements.

Ideal Applications for BLDC Motors

We’ve seen that BLDC motors offer high efficiency and controllability, and that they have a long operating life. They are widely used in devices that run continuously. They have long been used in washing machines, air conditioners, and other consumer electronics; and more recently, they are appearing in fans, where their high efficiency has contributed to a significant reduction in power consumption.

They are also being used to drive vacuum machines. In one case, a change in the control program resulted in a large jump in rotational speed—an example of the superlative controllability offered by these motors.

BLDC motors are also being used to spin hard disc drives, where their durability keeps the drives operating dependably over the long term, while their power efficiency contributes to energy reduction in an area where this is becoming increasingly important.