kommutaattori

Kommutaattori is a Finnish term that translates to "commutator" in English. In electrical engineering, a commutator is a key component in direct current (DC) electric motors and generators. Its primary function is to reverse the direction of the electric current in the rotor coils at the appropriate moment during each rotation. This reversal is essential for maintaining continuous torque in a motor and for generating a direct current output in a generator.

The commutator typically consists of a cylinder made of conductive material, segmented by insulating material. These segments are connected to the ends of the rotor coils. Stationary brushes, usually made of carbon, press against the rotating commutator. As the rotor spins, the brushes slide from one commutator segment to the next, effectively switching the electrical connections to the coils. This switching action ensures that the magnetic poles within the motor or generator are always interacting in a way that produces rotation or induces current.

The design and operation of a commutator are critical for the performance of DC machines. Issues such as worn brushes, dirty commutator segments, or incorrect timing of the current reversal can lead to reduced efficiency, sparking, and damage to the machine. While AC motors often do not require a commutator due to the alternating nature of the power supply, it remains a fundamental part of many DC motor and generator designs.