Monitoring device for the insulation resistance of the series current flight circle of a firing installation space

摘要

1. A monitoring device for the insulation resistance of the series circuit of an airport lighting system, wherein the individual airport lights are connected to one another and to the alternating voltage source by means of sections of a cable, comprising a measuring circuit which is to be connected between an end of the conductor of the cable and a reference point insulated against the latter and which comprises in series connection a direct voltage source, a suppression choke and a limit value generator, which responds to the measuring direct current, characterised in that the suppression choke (D) has a secondary winding (D') which feeds an opposing magnetization circuit with a controllable resistance (T1), and that this controllable resistance is dependent upon the current of the measuring circuit in such manner that when the current in the measuring circuit increases, the resistance drops, and that the opposing magnetization circuit comprises a valve (GI1) which is poled in such manner that the current flowing in the opposing magnetization circuit counteracts the premagnetization of the suppression choke (D) by means of the measuring direct current.