Current limiting reactor

[2] The inventor of the current limiting reactance coil was Vern E. Alden who filed the patent on November 20, 1917 with an issue date of September 11, 1923.

The inductive reactance is chosen to be low enough for an acceptable voltage drop during normal operation, but high enough to restrict a short circuit to the rating of the switchgear.

The amount of protection that a current limiting reactor offers depends upon the percentage increase in impedance that it provides for the system.

[5] It is desirable that the reactor does not go into magnetic saturation during a short circuit, so generally an air-core coil is used.

The most common type is designed for three-phase electric power, in which three isolated inductors are each wired in series with one of the three line phases.