Which type of motor does not have any brushes?

The correct answer is the squirrel cage induction motor, which operates without brushes. This type of motor relies on electromagnetic induction to create rotational motion. It comprises a rotor (the squirrel cage) that is typically made of conductive bars shorted at both ends, positioned within a stator that generates a rotating magnetic field. Since the motor design itself does not include brushes, the potential for wear and maintenance issues associated with brushes is eliminated.

In contrast, universal motors and brushed DC motors both employ brushes to conduct electrical current to the rotor, which is essential for their operation. Step motors, while they also do not use brushes, operate on a different principle entirely that involves discrete step movement based on electrical pulses. This is why, among the given choices, the squirrel cage induction motor is distinguished as not having any brushes.