Brushed motors and brushless motors are two common types of motors used in quadcopters, or drones in general. In this article we are going to discuss the differences between them.
Construction Differences of Brushed and Brushless Motors
A “brushed” motor has a rotating stator (wire coils) which acts as an electromagnet with two poles. The shell is stationary (not moving) therefore brushed motors can often be mounted without using any screws.
A “brushless” motor uses a permanent magnet and accomplishes the switching by electronically switching the polarity, instead of brushes, hence the name “brushless”. Because of the moving motor bell, the motor is usually mounted by the base using screws.
Advantages of Brushed Motors
- Inexpensive to make
- Can be made in small package
- Favourable in extreme environments due to lack of electronics
- Replaceable brushes for extended life
- Two wire control – control is simple; Brushless motors have 3 wires and require speed controller to work
- No speed controller is required for fixed speed
Popular applications: fan motors, power tools, small motorized toys and computer peripherals.
Advantages of Brushless Motors
- No brushes – lower maintenance and longer durability
- Better speed and torque due to the absence of brushes, because brush friction increases with speed
- Wider speed range
- Better heat dissipation due to the construction compared to brushed motors
- More cost effective for high speed/power operations
Popular applications: radio controlled model airplanes and drones, electric vehicles and industrial machinery that requires high rotation speed and power
Usage of Motors in Drones
Brushless motors seems to be the far more favourite choice, they are used in almost all types of drones. The only exceptions are the lower power micro drones running 1S LiPo batteries. A good example would be the Tiny Whoop. For anything more powerful, brushless motors are preferred.
Brushed motors designed for multirotors in this hobby only support 1S LiPo, maybe 2S at most. Brushless motors support much higher voltages, from 1S up to 12S. The popular motors we use on 5″ racing drones are rated for 4S to 6S.
Here are the available brushed motors in different dimensions, diameter x height (both in mm). Bigger motor = more power.