Significant Differences Between Brushless and Brushed Motors

Significant Differences Between Brushless and Brushed Motors

As two common types of DC motors, brushless and brushed motors exhibit significant differences in structure, operating principles, performance, and application scenarios.

In terms of structure and commutation methods: Brush motors rely on mechanical commutators and carbon brushes for current reversal. The commutator rotates coaxially with the rotor, altering current direction through brush contact with commutator segments. While structurally simpler, this design incorporates wear-prone mechanical components like brushes and commutators. Brushless motors eliminate mechanical commutators and carbon brushes, employing electronic commutation technology. Position sensors detect the rotor's position, and an electronic controller manages current switching in the stator windings to achieve contactless commutation. Structurally, they consist of a stator (containing windings), a rotor (permanent magnet), and electronic control circuits, with no mechanical wear components.

Regarding performance and lifespan: Brushed motors generate sparks, noise, and energy loss during operation due to friction between carbon brushes and commutators, resulting in lower efficiency. Carbon brushes wear rapidly, shortening lifespan and requiring periodic replacement during maintenance. Brushless motors eliminate mechanical friction, producing low operational noise, no sparks, minimal energy loss, and higher efficiency. Absent carbon brush wear significantly extends lifespan, reduces maintenance costs, and enhances reliability.

Regarding control and speed regulation, brushed motors offer simple control—speed adjustment is achieved by modifying voltage—but they have a narrow speed range and low control precision, making complex torque or speed closed-loop control difficult. Brushless motors require dedicated controllers. Utilizing PWM (Pulse Width Modulation) technology, they enable precise control of current, voltage, and frequency, achieving stable speed regulation across a wide range (from low to high speeds). They support high-precision closed-loop control of speed, torque, and position, making them suitable for automation and precision control applications.

By application scenario: Brushed motors, due to their low cost and simple structure, are suitable for scenarios with less stringent requirements for lifespan and precision. Brushless motors, owing to their high efficiency, long lifespan, and flexible control, are widely used in fields demanding higher performance.