Corona discharge monitoring for grooved stator dynamos - using HF signal pick=up aerial on rotor and position transducer

摘要

A corona discharge monitoring arrangement, esp. for dynamo machines with a rotor and a stator and isolated conductors placed in slots in the stator, operates satisfactorily whilst the machine is functioning. It does not use the unsatisfactory acoustic detection method. An antenna mounted on the rotor turns with it and receives signals arising from corona discharges in the grooves as it passes by them. The received signals are passed to an external evaluation circuit. The latter also receives a rotor position signal and synchronises the two signals so as to enable display of the incidence of h.f. signals with reference to position on the stator. The transfer of signals is via a rotary coupling consisting of a dual circular track arrangement with terminating impedances on each track.