What malfunctions can brush and commutator wear cause in a brushed DC motor?

1. Common Fault Types

Brushed DC Motor Does Not Turn or Has Difficulty Starting: Poor contact between the brush and commutator prevents current from flowing smoothly into the rotor.

Unstable Speed: Wear causes fluctuations in contact resistance, leading to voltage fluctuations and consequently, speed instability.

Noise and Sparks: Brush material shedding or uneven commutator surfaces can generate noticeable arcing noise.

Abnormally Increased Current: Reduced contact area increases resistance, causing the brushed DC motor's operating current to rise and accelerating wear.

2. Wear Mechanism

Mechanical Wear: The brushes (usually carbon brushes) rub against the commutator surface, gradually thinning over time.

Electrical Wear: Under high current or high temperature conditions, an electric arc can occur between the brush and commutator, causing material to melt and detach, increasing contact resistance.

3. Failure Consequences

Sharply Reduced Brushed DC Motor Lifespan: Severe wear can cause pitting on the commutator surface, leading to motor failure.

Failure Consequences: Safety Hazards: Sparks may ignite flammable environments, especially in dusty or oily areas.

Increased Maintenance Costs: Frequent brush replacements or commutator repairs increase downtime and maintenance costs.

4. Maintenance Measures to Extend Lifespan

Use High-Quality Carbon Brushes: These are more wear-resistant and have better conductivity, significantly reducing wear rates.

Keep the Working Environment Dry: High humidity accelerates electrical wear. Regularly clean the commutator surface to prevent dust accumulation.

Use Properly: Avoid prolonged full loads and frequent start-stop cycles to reduce impact between the brushes and the commutator.

Regular Inspection: Monitor brush thickness and commutator surface wear, and replace brushes promptly.