Brushless motor technology has been the rage in cordless power tools the last couple of years. In a tool with a brushless motor, the motor adjusts according to the task. The more resistance a drill or saw senses, the more power it draws, and conversely a lack of resistance lessens the pull.
Then, what is the difference between a brushed and brushless motor?
Brushless motors are typically 85-90% efficient whereas brushed DC motors are around 75-80% efficient. This difference in efficiency means that more of the total power used by the motor is being turned into rotational force and less is being lost as heat.
Why is a brushless motor better?
A brushless motor loses the brushes and the commutator. Because the copper windings are on the outside of the motor configuration, there is room to make them larger. Brushless motors also don't have the friction and voltage drop that brushes create by dragging against the spinning commutator.
What is a brushless AC motor?
Brushless DC motors are similar to AC synchronous motors. The major difference is that synchronous motors develop a sinusoidal back EMF, as compared to a rectangular, or trapezoidal, back EMF for brushless DC motors. Both have stator created rotating magnetic fields producing torque in a magnetic rotor.