Method for determining the operating status of a spring charging motor for a LV or MV switching apparatus and a diagnostic system implementing said method

A diagnostic system for determining the operating status of a spring charging motor of a switching apparatus wherein it comprises:

• sensing means adapted to provide a detection signal (ID) indicative of the behaviour of a driving current (IMOT), which feeds said spring charging motor, and a first control unit configured to:
• acquire a detection signal (ID) indicative of the behaviour of said driving current (IMOT) during an operation cycle of said spring charging motor;
• process said detection signal (ID) to calculate a steady-state detection signal (IDSS) indicative of the behaviour of said driving current (IMOT) during a steady-state time interval (TSS) comprised in the operation cycle of said spring charging motor;
• process said steady-state detection signal (IDSS) to calculate data (DS) indicative of high frequency and low frequency spectral components of said driving current (IMOT) during said steady-state time interval;
• process said data (DS) indicative of said high frequency and low frequency spectral components to calculate first and second harmonic distortion values (THDLF, THDHF), which are indicative of the total harmonic distortion of said high frequency and low frequency spectral components, respectively;
• processing said first and second harmonic distortion values to calculate first and second output data (O1, O2), which are indicative of the variations of said first and second harmonic distortion values with respect to corresponding first and second reference values, respectively.