A commutator is primarily found in which type of equipment?

A commutator is primarily found in DC motors, where it plays a crucial role in the operation of the motor. The commutator is a mechanical switch that reverses the direction of current flow through the motor windings every half cycle of rotation. This reversal is necessary to maintain the rotational motion of the motor. Without the commutator, the motor would just oscillate back and forth instead of rotating continuously.

In a DC motor, the commutator works in conjunction with the brushes to ensure that the current flows in the correct direction to interact with the magnetic fields generated by the stator. This interaction is what produces the torque that drives the motor's shaft.

In contrast, AC motors do not require a commutator because they rely on alternating current to produce a rotating magnetic field, which does not need a mechanical switching mechanism. Capacitor banks and transformers also do not use commutators, as they operate based on different principles of capacitive storage and magnetic induction, respectively.