I know a brushed motor is mechanical and brushless is electric. Brushless is more efficient and creates less heat. But how does each work and why is there an advantage of one over the other?
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In short, physical contact between the rotor and the stator.
In a typical brushless motor, multpliphase power (usually 3 phase AC) is sent to stationary coils in the central stationary portion of the motor (called the stator). This produces an electromagnetic force that pulls the rotor around the outside via a bank of permanent magnets mounted to the rotor. In such a setup, the bearings physically mounting the rotor and stator together are the only point of contact between the two major components.
In a typical brushed motor, the magnets are on the stator and power is sent through coils on the rotor to create the force to turn the rotor. The contacts that transfer the current to the rotor are what we call the brushes. Insulated gaps that the brushes pass over create the different phases in the current to allow the motor to turn.
A motor has to have a changing magnetic field to achieve rotation. A brushed motor has a carbon block that rides on a bunch of little copper contacts acting as switches to constantly switch power to the proper coil of wire to change the magnetic field in the windings and spin the motor.
A brushless motor is electrically or electronically switched so that the magnetic field can be changed without any mechanical “switch”.
A motor works by creating a rotating magnetic field, which pushes against stationary magnets to turn the motor.
The difference between brushed and brushless motors lies in how they create the rotating magnetic field. A brushed motor uses electrical contacts between the stationary part of the motor (stator) and rotating part (rotor). These contacts are called brushes, and are usually blocks of graphite which rub against copper contacts on the rotor. As the motor spins, the brushes touch different contacts, energizing different electromagnets and creating a rotating magnetic field.
A brushless motor does not use electrical contacts between the rotor and stator. Instead, a motor controller circuit turns on and off the coils, usually using computer control. This eliminates a source of noise and mechanical wear, but generally the motor controller costs quite a bit more than a simple brushed motor would.
Brushed is still electric. They’re both types of electric motors.
In a brushless motor the electric field generated is constantly changing, which produces a rotating force on the motor to turn it around. You can think of this as AC, though in reality if you call it a brushless motor it’s probably technically DC being converted to a somewhat ac signal.
In a brushed motor the supply is DC. It always pushes in one direction. This would result in the motor doing a half turn and no more. To get around this there is a physical brush that skims over the rotating part – as it rotates the connections reverse when the motor turns to the other side which reverses the push of the DC current and results in a rotating field, which rotates the motor
You can think of a brushed motor like a bike pedal. Without a brush it will only push down, it cannot pull up. Your pedal will go down and never back up, and you can’t cycle. The brush reverses things and allows you to pull up, meaning you can actually move. When it gets back to the top it reverses again and you can now push again.
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