[Inside the EV Heart] Part 1: The Motor That Sparks? Meet the Classic "Brushed DC Motor"
Many people think the soul of an electric vehicle is the massive battery pack in the chassis. Honestly, the battery just "holds the juice." What truly determines whether you can leave the gas car next to you in the rearview mirror when you stomp on the accelerator is the furiously spinning "motor" underneath.
However, before we introduce you to those 2026 alien technologies boasting thousands of horsepower, we need to dig into a "living fossil" of the motor world: the Brushed DC Motor.
Why call it a living fossil? Because it has been completely "exiled" by the powertrains of modern EVs.
Why Does a Motor Spin? It is Actually Just Two Magnets Fighting
Do not overcomplicate the motor. Its underlying logic is exactly like the magnets you played with as a kid: "like poles repel, opposite poles attract."
If you open the casing of a brushed motor, you will see two main parts:
- Stator: The stationary outer casing, usually fitted with permanent magnets, responsible for providing a stable magnetic field.
- Rotor: The spinning shaft in the middle, wrapped in coils of copper wire.
When we run electricity through the copper wire, it becomes an "electromagnet." This electromagnet repels and attracts the permanent magnets on the casing, pushing the rotor to spin.
What Exactly is the "Brush" in a Brushed Motor? The Secret Behind the Sparks
Here comes the biggest problem: with the rotor spinning like crazy in the middle, how do you connect the external power wires to it without them twisting into a dead knot?
The brute-force solution engineers came up with is to attach a metal ring (commutator) to the rotor shaft, and then use two spring-loaded "Carbon Brushes" that press tightly against this high-speed spinning ring to conduct electricity.
This is exactly where the name "brushed" motor comes from.
But physics is fair; wherever there is friction, there will be issues. The carbon brushes constantly rubbing against the rapidly spinning metal ring not only cause wear and noise, but under high loads, they also crackle and generate blue-orange "arcing" (electrical sparks).
Has It Been Made Obsolete by EVs?
Friction generating heat, sparking, and short lifespans mean the energy conversion efficiency of this motor is usually a pitiful 75% to 80%. This is exactly why modern EVs "absolutely never" use brushed motors to drive the wheels; they are too power-hungry and prone to failure.
But do not hold a moment of silence for it just yet. Because of its extremely simple construction and ultra-low cost, you can easily control its speed just by changing the voltage. So today in 2026, it has pivoted to doing the "grunt work" in cars that only require occasional movement. Things like your power seat adjustments, wiper motors, or the power tailgate almost all still rely on this veteran.
Engineers are a bunch of neat freaks. Since carbon brushes create friction, sparks, and wear out easily, the most direct solution is to: remove the brushes!
But once you remove the brushes, how do you get power to the motor? In the next article, we will crack the clever design that revolutionized drones and cooling fans across the board: "The Inside-Out Magic of the Brushless DC Motor (BLDC)."
