Can a brushed DC motor generate electricity?

The answer is yes. A brushed DC motor can not only consume electricity to do work, but it can also "generate" electricity in reverse. This is because motors and generators are essentially the same thing in terms of their physical structure.

Here's a detailed explanation of how it transforms into a generator:

1. The Principle of Role Reversal

When you power a motor, it converts electrical energy into rotational force; but if you do the opposite, using external force (such as turning the shaft by hand, wind, or water flow) to rapidly rotate the motor's shaft, the internal coils will quickly cut through the magnetic field of the magnets. At this point, a current will be generated in the coils that were originally used for rotation. This is what we commonly call "reverse operation."

2. Why it's a "ready-made" generator

Built-in magnetic field: Brushed DC motors already have magnets installed, eliminating the need for additional power to generate magnetic force, allowing them to enter the power generation state anytime, anywhere.
The commutator's contribution: This is key to the Brushed DC Motor generating direct current. Although the coils produce alternating current that oscillates back and forth, the mechanical cooperation of the brushes and commutator automatically rectifies the direction of the current, making the output electricity direct current, which can light up a small light bulb.

3. Practical Applications in Daily Life

Hand-cranked power generation: Many emergency hand-cranked flashlights actually contain a miniature brushed motor. When you turn the handle, you are essentially driving the motor to generate electricity.
Kinetic energy recovery: In some electric scooters or children's cars, when you release the accelerator or coast downhill, the rotation of the wheels drives the motor. At this point, the motor becomes a generator, sending the generated electricity back to the battery or using it to assist in braking.

4. What Affects the Power Generation Effect

Rotation speed: The faster you rotate it, the stronger the current it generates. If you only rotate it slowly, the generated electricity may be too weak to power anything.
Resistance feeling: When you connect the motor to a light bulb and start generating electricity, you will find that the rotating shaft becomes heavier. This is because electrical energy is being converted; the force you exert is ultimately transformed into light and heat.

5. Precautions

Although it can generate electricity, it is ultimately designed according to motor standards. If it is rotated for a long time at high intensity like a professional generator, the internal brushes will wear out due to overheating from friction. Therefore, it's fine for occasional emergency use or small science experiments, but for serious power generation, professional equipment is necessary.