How does a brushed DC motor work&Brushed DC VS BLDC motors

A Brushed DC Motor is a motor that uses a mechanical commutator and brushes to change the direction of the current to achieve continuous rotation. Here's how it works and a detailed comparison of brushed and brushless motors:

The working principle of a brushed DC motor

• Basic structure

1. Stator: Usually made of permanent magnets that provide a constant magnetic field.

2. Rotor (armature): Consists of windings and iron core, which interacts with the magnetic field of the stator.

3. Commutator: connect the rotor winding, responsible for switching the current direction.

4. Brushes: In contact with the commutator, an external current is introduced into the rotor windings.

• Run the process

1. When the current passes through the rotor windings, an electromagnetic force (according to the left-hand rule) that interacts with the stator magnetic field will be generated to drive the rotor to rotate.

2. When the rotor rotates, the switching function of the commutator changes the current direction at an appropriate time, and the magnetic field of the rotor winding and the stator magnetic field always produce torque.

3. The rotor rotates continuously, so as to complete the energy conversion.

• Energy transfer

Electrical energy → magnetic energy → mechanical energy (output torque and speed).

Comparison of brushed and brushless motors

1. Structure

Brushed motor: There are brushes and mechanical commutators

Brushless motor: brushless, electronically commutated (via Hall sensor, etc.)

2. Maintenance requirements

Brushed motors: The brushes need to be replaced regularly and the commutator cleaned

Brushless motor: basically maintenance-free and long life

3. Efficiency

Brushed motors: low (energy loss due to friction between brushes and commutators)

brushless motors; High (no mechanical friction, more efficient energy conversion)

4. Lifespan

Brushed motors: shorter (brushes wear out faster, especially under high loads)

Brushless motors: long (no wear parts, life is usually determined by bearings)

5. Control complexity

Brushed motor: simple, directly controlled by voltage and current

Brushless motors: more complex and require an electronic controller (ESC) to regulate the operation

6. Noise

Brushed motors: higher (due to friction between brushes and commutators)

Brushless motor: low (no mechanical commutation noise)

7. Cost

Brushed motor: low, simple production process

Brushless motors: higher (requires complex control circuits and more sophisticated components)

8. Application scenarios

Brushed motors: suitable for low-cost, low-precision equipment (e.g. toys, power tools)

Brushless motor: suitable for high-efficiency, low-noise, high-precision scenarios (such as drones, electric vehicles)

9. Start-up performance

Brushed motor: high starting torque

Brushless motor: The starting torque is low, but it can be optimized by control

10. Thermal management

Brushed motors: heat is concentrated in the rotor (attention needs to be paid to heat dissipation)

Brushless motor: heat is concentrated in the stator (easier to dissipate heat)

Application scenario analysis

Brushed motor

1. Advantages: simple control, high starting torque, low cost.

2. Applicable scenarios: toys, portable power tools, small household appliances, etc.

Brushless motor

1. Advantages: high efficiency, long life, low noise, suitable for high-precision control.

2. Applicable scenarios: drones, fans, electric vehicles, industrial automation equipment, etc.

Summary

• Brushed motors are suitable for cost-sensitive scenarios with low requirements for life and noise.
• Although brushless motors are expensive, they have significant advantages in efficiency, life and performance, especially in scenarios with high control requirements.

If you need more detailed technical instructions or selection suggestions, you can discuss further!