Regulating the electric power sent to an electric motor is a task performed by high-speed switching transistors inside a motor drive, modulating the pulse-width of a high-frequency square wave to the motor. As a result of this High-frequency current and voltage noise appears at input terminals of Motor Drives as explained earlier.
One of the useful methods to combat these effects is to filter harmonic frequencies from the rest of the AC power system, preventing the subsequent “corruption” of the AC power source by the motor drive’s pulsing currents. The most direct way to filter harmonic frequencies is to use an electrical component acting as a low-pass filter – a simple inductorconnected in series with the motor drive. For three-phase-powered motor drives, this takes the form of three inductor elements, commonly referred to in industry as reactors:
Further Reading/reference:
- Application of line reactors to AC and DC motors
- Download complete PDF article on Motor Drive Features and Application of Line Reactors Handbook PDF Download
- DC injection braking
- Dynamic braking of AC Induction Motors
- Regenerative braking of AC Induction Motors
- Braking using Plugging