CONTROL TRANSFORMER LINE CHOKE The use of line chokes is recommended in particular under the following circumstances: Close connection of several drives in parallel Line supply with significant disturbance from other equipment (interference, overvoltages) Line supply with voltage imbalance between phases above 1.8% of the nominal voltage Drive power supplied by a line with very low impedance (in the vicinity of power transformers 10 times more powerful than the drive rating) Installation of a large number of frequency inverters on the same line Reduction of overloads on the "cos phi" correction capacitors, if the installation includes a power factor correction unit.