When the local utility switches power factor correction capacitors onto the electrical power grid, it creates voltage spikes. The proper impedance reactor in the input circuit virtually eliminates nuisance tripping of drives due to these voltage spikes. Also, the reactor can protect from line sags because it performs a line stabilizing function. Initially, this may seem unusual because the reactor adds impedance to the circuit, which causes a voltage drop. An important, overlooked factor is that the reactor has significant inductance so it opposes any rapid change in current.
Most voltage sags are the result of excessive loading or current surges.
Thus, by stabilizing the current waveform, the reactor can indirectly solve both overvoltage and undervoltage tripping problems. Looking on the line side from the opposite direction, the reactor filters out both pulsed and notched distortion. The line reactor has been proven effective in reducing harmonics emitted by the drive onto the incoming power line. Reactor Impedance Line reactors are rated in percent impedance to retain some conformity with the ratings of conventional drive isolation transformers. Increase the primary voltage while monitoring secondary current.