Method for estimating an operating state of an electrical switching apparatus and electrical switching apparatus for implementing such a method

An electrical switching apparatus configured to be coupled to an electrical conductor and comprising:

• separable contacts, configured to be moved between an open position and a closed position by an electromagnetic actuator comprising a coil and a movable core linked to the separable contacts;
• a control circuit configured to control electrical voltage at terminals of the coil, the control circuit comprising a fallback device configured to be selectively activated to reduce electrical current passing through the coil, with the voltage at the terminals of the coil and the fallback device being activated or deactivated according to states of the control circuit;
• sensors associated with the coil for measuring the current passing through the coil;
• an electronic control device, configured to receive opening and closing commands from the switching apparatus, to receive values of the measured current passing through the coil and to control the states of the control circuit;
• wherein, while the electromagnetic actuator is kept in a stable position, the switching apparatus is configured to:
• measure, by means of the sensors associated with the coil, values of current passing through the coil during a time interval;
• compute, by means of the electronic control device, a value of a magnetic flux of the coil from the measured values of the current passing through the coil during the time interval, and using previously known values of voltage at the terminals of the coil and coil resistance;
• and
• use the computed value of the magnetic flux of the coil to estimate a state of the electrical switching apparatus.