What device is responsible for changing the direction of current flow through the armature loop?

The correct device responsible for changing the direction of current flow through the armature loop is the commutator. In a direct current (DC) motor or generator, the commutator works in conjunction with the brushes to ensure that the current flowing through the armature is reversed at the appropriate times during its rotation. This reversal is essential for maintaining the rotation of the armature in one direction, allowing the motor to produce continuous rotational motion or the generator to maintain a consistent output.

When the armature rotates, the commutator periodically connects different segments of the winding to the external circuit. This switching action keeps the torque in one direction, preventing the armature from stopping when it reaches the zero position of the magnetic field. The efficiency of this process is key to the operation of motors and generators, as it translates electrical energy into mechanical energy and vice versa.

Understanding the function of the commutator is crucial for anyone working with DC motors and generators, as it plays a vital role in the conversion of energy types within these devices.