What's the Difference Between Brushless Motors and Brush Motors?

As we already know, there are a lot of portabledental unit for sale, and among them, two types of Motors are available now, they are Brushless Motors and Brush Motors. Then, what's the difference between them?

Well, of course the difference is the brushes! But what does that mean?

The internal working principle of the brushless DC motor and the brushed DC motor is basically the same. When the motor windings are energized, a temporary magnetic field is generated that resists (and/or attracts) the permanent magnets. This force is converted to shaft rotation, allowing the motor to do work. As the shaft rotates, current is delivered to different sets of windings, maintaining electrical repulsion/attraction, forcing the rotor to rotate continuously.

Construction Differences

A brush in the motor is used to deliver current to the motor windings through the commutator contacts. Brushless motors do not have these current-carrying commutators. The magnetic field within the brushless motor is switched by an amplifier that is triggered by a commutation device, such as an optical encoder.

Windings are on the rotor for a brushed motor (rotating part of motor) and on the stator for a brushless motor (stationary portion of the motor). By positioning the windings on the outer stationary portion of the motor, the need for a brush can be eliminated.

Advantages of Brushed motor

Simplified wiring: Brush motors can be wired directly to DC power and control can be a simple as a switch.

Low cost

Disadvantages of Brushed Motor

Less efficient

Electrically noisy: The switching action of the commutators constantly creating and breaking inductive circuits creates a great deal of electrical and electromagnetic noise.

Short Lifespan: As they are in perpetual physical contact with the shaft, brushes and commutators wear out.

Advantages of Brushless Motor

Long lifespan: No brushes to wear out

low maintenance: No brushes to replace

High efficiency

Disadvantages of Brushless Motor

High initial cost: Need for commutating device like an encoder and a drive or controller

Efficiency Difference Between Brushless motor and brush motor:

The efficiency of brushless dental micromotor is typically 85-90%, while the efficiency of brushed DC motors is about 75-80%. This difference in efficiency means that more of the total power used by the motor is converted to rotational force and less power is lost as heat.