TS Line Chokes serve for suppression of adverse effects caused by some appliances in the electric network.  One-phase appliances are implied - the appliances connected between phase and neutral conductor (zero) (230V) or connected between two phases (400V). Typical examples of such appliances are frequency converters, controlled and uncontrolled rectifiers and switching power supplies. By inserting a line chokes between the appliance and the network connection we suppress commutation effect and current surges caused by capacitance in DC circuits, and also suppress EMI caused by switching of power semiconductor components. Using of line chokes also increases reliability of frequency converters and improves EMI suppressing filters. The line chokes are designed so that they are equivalent to supply transformers with ek = 4% at voltage 3 x 400V/230V and frequency 50 Hz. Details see in  pdf