Brushless motors used in electric skateboards offer more power and longer run times than conventional brushed motors of the same size. The superior power, efficiency, lighter weight and quietness of brushless motors make them the ideal choice for high performance electric skateboards.
The Brushed Motor in electric skateboards function through the creation of magnetic fields whose attraction and opposition keeps a central rotor turning. In a brushed motor, fixed magnets are placed on either side of a rotating electromagnet, one oriented to a positive pole, the other to a negative one. The electromagnet is formed by a series of coils (usually three placed at equidistant points around the rotor) called the commutator. When electricity is passed through these coils they generate their own magnetic field that is repelled and attracted to the magnetic fields generated by the fixed magnets. Current is transferred to the coils of the commutator by metallic brushes which rotate along with the rotor. When the motor is switched on, current is passed to the electromagnets whose magnetic fields are repelled by one fixed magnet and attracted to another, causing the rotor to turn. As the rotor turns, the metallic brushes come into and out of contact with each coil in series so the opposition and attraction between the resulting magnetic fields and the fields of the static magnets keeps the electromagnet turning.
In a Brushless Motor the positions of the fixed magnets and the electromagnetized coils are reversed. The fixed magnets are now placed on the rotor and the coils are placed in the surrounding casing. The motor functions via current being passed through each surrounding coil in series, so repulsing and attracting the fields of the fixed magnets and keeping the rotor they are attached to turning. For a motor of this kind to work, the coils of the commutator need to be kept synchronized with the fixed magnets so that the fields are continually in opposition and the rotor is kept turning. This requires an electronic controller or microprocessor to coordinate the application of current to each electromagnetic coil.
Brushed Motor Pros. Operates in extreme environments due to lack of electronics. Some can be rebuildable for extended life and they have a low cost of manufacturing.
Brushed Motor Cons. Periodic maintenance is required. Speed/torque is moderately flat. When the electric skateboard travels at high speeds the brush friction increases, thus reducing useful torque.Poor heat dissipation due to internal rotor construction and higher rotor inertia limits the dynamic characteristics. It has a lower speed range due to mechanical limitations on the brushes. Brush arcing on the electric motor will generate noise causing electrical magnetic interference (EMI)
Brushless Motor Pros.Electronic commutation based on position sensors vs mechanical switch for brushed. Less maintenance due to absence of brushes. Speed/Torque- flat, enables operation at all speeds with rated load. High efficiency, no voltage drop across brushes. High output power to size ratio. Reduced size due to superior thermal characteristics. Because the windings are connected to the case the heat disipation is better. Higher speed range – no mechanical limitation imposed by brushes/commutator. Low electric noise generation (EMI)
Brushless Motor Cons. Higher cost of construction. Electric controller(ESC) is required to keep the motor running which is sometimes more expensive than the motor.