What is brushless DC motor and how brushless DC motor works

A Brushless DC Electric Motor (BLDC) is an electric motor powered by a direct current voltage supply and commutated electronically instead of by brushes like in conventional Brushes electric DC motors. BLDC motors are more popular than the conventional DC motors nowadays, but the development of these type of motors has only been possible since the 1960s when semiconductor electronics were developed.

Brushless dc motor product it is expensive at the beginning,  because motor is a little expensive and also need a bldc drive circuit board or controller board to give it power signal. However, brushless motor is long-life lasting, in a long term, brushless products is cheaper. and product with brushes motor,  each time the motor rotate, the brushes are constantly rubbing against the commutator, they eventually wear out. and the rubbing process also generate a lot of heat, it can easily damage the motor soon.

Here below is a example of brushless drill and a brushed drill.  This animation clearly reveal the difference between brushless motor and brushes motor. 

By comparison, the brushless DC motor (BLDC) has 3 advantage

1: BLDC motor has lower noise than brushed motor

2: BLDC motor product has higher power efficiency

3: BLDC motor has a longer lifespan than brushed motor, in this way,  cheaper to maintain.