In DC motors, which component reverses current direction to maintain rotation?

In DC motors, which component reverses current direction to maintain rotation?

• A. Brushes
• B. Rotor
• C. Stator
• D. Commutator

Answer: (D)

To keep the motor turning in one direction, the current in the rotor windings must be reversed each time the coil passes the point where the torque would try to flip sign. The commutator does this by acting as a mechanical inverter: as the rotor turns, it switches the connections of the winding to the power source through the brushes, reversing the current every half turn. This maintains torque in the same direction throughout rotation. The brushes simply provide electrical contact; they don’t reverse current themselves. The rotor (armature) is the rotating part that carries the windings, and the stator provides the fixed magnetic field.

To keep the motor turning in one direction, the current in the rotor windings must be reversed each time the coil passes the point where the torque would try to flip sign. The commutator does this by acting as a mechanical inverter: as the rotor turns, it switches the connections of the winding to the power source through the brushes, reversing the current every half turn. This maintains torque in the same direction throughout rotation. The brushes simply provide electrical contact; they don’t reverse current themselves. The rotor (armature) is the rotating part that carries the windings, and the stator provides the fixed magnetic field.