Reactors can be used as current-limiters to resist sudden current changes, hindering spikes and peaks and protecting against short-circuiting. They are commonly created for three-phase electrical power, but they are also available for single phase power. Connected to the line in series, they are a perfect source of impedance.
Line and load reactors serve related purposes in similar situations. Line reactors are on the line side of the drive Variable Frequency Drives (VFD). Particularly when the drive is close to the power source, reactors can be essential in protecting it from spikes. They can also lessen the effects of harmonics on the drive, especially when it is farther away from the source. Similarly, line reactors can filter pulse distortion to help the drives run more smoothly and protect connected computers and Programmable Logic Controllers (PLCs).
Load reactors are often used in tandem with line reactors. They are on the load side of the drive or at the input of the motor. Like with drives, the reactors can counteract harmonics and guard them from peaks and spikes. For motors, the issue is more specifically the “long lead effect”. Because motors and drives are commonly separated by substantial distances, there is more room for larger peaks. These peaks can wear out the motors quickly and damage the system, but reactors can soften the blow. Looking in the other direction, reactors can protect the drives from the motors. If there is a short-circuit, the reactors slow the current in between the motor and drive enough to allow the protection circuits time to trip.
Both line and load reactors can reduce audible noise in the drives and motors. Reducing peaks also helps to reduce heating, giving the system a longer lifespan.
You may also be interested in reading: